A tin-bismuth bimetallic oxysulfide electrode material modified with cation and anion vacancies, its preparation method and application

Abstract

This invention discloses a tin-bismuth bimetallic oxysulfide electrode material modified with dual vacancy sites for cations and anions, its preparation method, and its application, belonging to the field of battery materials technology. The tin-bismuth bimetallic oxysulfide electrode material is Bi2S3@Sn. 0.904 O2 heterojunction, Sn 0.904 O2 nanoparticles are loaded onto Bi2S3 nanorods; the Bi2S3 nanorods contain sulfide anion vacancies and Sn... 0.904 O2 nanoparticles contain tin cation vacancies. This invention prepares Bi2S3@Sn modified with tin cation and sulfide anion vacancies by controlling the inducing agent in the hydrothermal reaction process and the subsequent calcination process. 0.904 O2 heterojunction. When this material is applied to the negative electrode of lithium-ion batteries, it can effectively alleviate the volume expansion of tin-based oxysulfides, improve the conductivity of the electrode material, and exhibit high charge-discharge specific capacity, excellent rate performance, and high-rate long-cycle stability.

Description

Technical Field

[0001] This invention relates to the field of battery materials technology, specifically to a tin-bismuth bimetallic oxysulfide electrode material modified with dual vacancy sites of anions and cations, its preparation method, and its application. Background Technology

[0002] The advent of rechargeable batteries has significantly reduced global dependence on fossil fuels. Among these, lithium-ion batteries (LIBs), with their wide range of applications, have profoundly changed human lifestyles and played a crucial role in promoting green and sustainable development. As society continues to develop, the demand for high-energy-density battery devices with fast-charging capabilities continues to rise, highlighting the increasing limitations of existing graphite-based anode materials. Their theoretical capacity is only 372 mA hg. -1 Its poor rate capability makes it difficult to adapt to the ever-growing high-performance standards, thus necessitating a technological breakthrough.

[0003] Sn-based electrode materials have attracted much attention from researchers due to their high theoretical capacity. SnO2, as an important branch of tin-based materials, has become a core research area in the field of lithium-ion battery anode materials due to its advantages such as high theoretical capacity, abundant resources, and environmental friendliness. However, these electrode materials suffer from problems such as drastic volume expansion and contraction and rapid capacity decay during charge-discharge cycles, which greatly restricts their transformation from laboratory research to large-scale commercial applications. To address this challenge, the electronic structure of SnO2 can be adjusted and its electrochemical reactivity enhanced by introducing heterogeneous interfaces or defect sites. For example, patent application CN120309007A discloses an oxygen-sulfur dual-vacancy modified SnO2 / SnS2 / C nanomaterial, its preparation method, and its application, which improves the electrical performance of the material by introducing two types of defect sites: oxygen vacancies and sulfur vacancies. Phosphorus doping induced the co-construction of sulfur vacancies and heterojunctions in tin disulfide as a durable anode for lithium / sodium ion batteries (Zhen Kong et al., Inorg. Chem. Front, 2022, 9, 902–913) prepared a tin-based sulfide / reduced graphene oxide composite material (SnS2-xPx / RGO) with a heterojunction. By controlling the sulfur vacancies in SnS2, the energy storage capacity of the material was improved through the preparation of a heterojunction and a defect site. The synergistic effect of the heterojunction interface also inhibited the dissolution and loss of active materials, reducing capacity decay. Defect sites can enhance ion / electron transport, optimize reaction kinetics, improve material stability, and increase active sites. However, there are many types of defect sites, such as vacancy defects and twin boundaries, and different defect sites have different functions. Currently, the key challenge is how to ingeniously construct a reasonable electrode material structure that has both multiple defect sites and heterogeneous interfaces, so that the electrode material can achieve high capacity under fast charging conditions while ensuring stable cycle performance. Summary of the Invention

[0004] To address the aforementioned limitations of existing technologies, the present invention aims to provide a tin-bismuth bimetallic oxysulfide electrode material modified with both cation and anion vacancies, along with its preparation method and applications. This invention utilizes a hydrothermal reaction between Bi₂S₃ nanorods and tin salts. By controlling the inducing agent and subsequent calcination process during the hydrothermal reaction, Bi₂S₃@Sn modified with tin cation vacancies and sulfur anion vacancies is prepared. 0.904O2 heterojunction. When this material is applied to the negative electrode of lithium-ion batteries, it can effectively alleviate the volume expansion of tin-based oxysulfides, improve the conductivity of the electrode material, and exhibit high charge-discharge specific capacity, excellent rate performance, and high-rate long-cycle stability.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] In a first aspect, the present invention provides a tin-bismuth bimetallic oxysulfide electrode material modified with dual vacancy sites for both cations and anions, wherein the tin-bismuth bimetallic oxysulfide electrode material is Bi2S3@Sn. 0.904 O2 heterojunction, Sn 0.904 O2 nanoparticles are loaded onto Bi2S3 nanorods; the Bi2S3 nanorods contain sulfur anion vacancies, and the Sn... 0.904 O2 nanoparticles contain tin cation vacancies.

[0007] A second aspect of the present invention provides a method for preparing a tin-bismuth bimetallic oxysulfide electrode material, comprising the following steps:

[0008] (1) Bismuth sulfide nanorods were dispersed in deionized water, and then tin salt, thioacetamide and polyvinylpyrrolidone were added in sequence and mixed evenly. Then, a hydrothermal reaction was carried out, the product was collected, washed and dried to obtain solid powder.

[0009] (2) The solid powder was calcined under a protective atmosphere to obtain a tin-bismuth bimetallic oxysulfide electrode material modified with anion and cation double vacancy.

[0010] Preferably, in step (1), the bismuth sulfide nanorods are prepared by the following method:

[0011] Bismuth salt and sulfide were dissolved in ethylene glycol, heated and stirred in an oil bath to obtain a black suspension. After filtration, washing and drying, bismuth sulfide Bi2S3 nanorods were obtained.

[0012] Preferably, the bismuth salt is Bi(NO3)3•5H2O or BiCl3; the sulfide is thiourea or thioacetamide; and the oil bath temperature is 80~110℃ and the time is 2~4h.

[0013] Preferably, the molar ratio of the bismuth salt to the sulfide is 0.1 to 0.15:1.

[0014] Preferably, in step (1), the tin salt is SnCl2•2H2O; the mass ratio of the bismuth sulfide nanorods, SnCl2•2H2O, thioacetamide and polyvinylpyrrolidone is 5:2.5~7:20~30:15~25.

[0015] Preferably, in step (1), the mixing is uniform by stirring until homogeneous and then ultrasonically dispersing for 30 minutes; the drying temperature is 60~80℃ and the time is 8~12h.

[0016] Preferably, in step (1), the temperature of the hydrothermal reaction is 180~200℃ and the time is 12h.

[0017] Preferably, in step (2), the calcination temperature is 550°C and the time is 2-3 hours.

[0018] A third aspect of the present invention provides the application of tin-bismuth bimetallic oxysulfide electrode materials in improving the performance of lithium-ion batteries.

[0019] Preferably, improving the performance of lithium-ion batteries includes improving conductivity, energy storage capacity, specific capacity, stability, lithium-ion transport efficiency, and reducing the ion transport barrier.

[0020] The beneficial effects of this invention are:

[0021] (1) Bi2S3@Sn prepared in this invention 0.904 O2 heterojunctions benefit from the nanorod structure with dual vacancy sites for anions and cations, which can alleviate volume expansion during energy storage and provide ion transport channels, giving the electrode material excellent rate performance and long cycle performance.

[0022] (2) In the electrode material prepared by this invention, the double vacancy and heterostructure greatly increase the active sites of the electrode material, while effectively alleviating the volume expansion of the electrode material during energy storage, enhancing the structural stability of the electrode material, and the synergistic effect of the nanorod structure can significantly improve the energy storage performance of the electrode material. It is expected to achieve a high rate and long cycle life of lithium-ion batteries. Attached Figure Description

[0023] Figure 1 (a) XRD patterns of Bi2S3@SnS2, (b) XRD patterns of Bi2S3@SnO2 and Bi2S3@Sn 0.904 XRD patterns of O2, (c) Bi2S3@SnO2 and Bi2S3@Sn 0.904 Local XRD patterns of O2, (d) Bi2S3@Sn prepared with different Bi:Sn ratios. 0.904 XRD pattern of O2;

[0024] Figure 2 (a) XRD pattern of Bi2S3@SnO2-350, (b) XRD pattern of Bi2S3@SnO2-650;

[0025] Figure 3(a) SEM image of Bi2S3, (b) SEM image of Bi2S3@SnO2, (c) SEM image of Bi2S3@SnO2 0.904 (d) SEM image of O2; (e) TEM image of Bi2S3@SnO2; (f) SEM image of Bi2S3@SnO2. 0.904 TEM image of O2; (f) Bi2S3@Sn 0.904 High-resolution TEM image of O2;

[0026] Figure 4 (a) SEM image of Bi2S3@SnO2-350 prepared in Comparative Example 2, (b) SEM image of Bi2S3@SnO2-650 prepared in Comparative Example 3;

[0027] Figure 5 :Bi2S3@Sn 0.904 Elemental energy spectrum of O2 composite material;

[0028] Figure 6 :Bi2S3@SnO2 and Bi2S3@Sn 0.904 EPR spectrum of O2;

[0029] Figure 7 :Bi2S3@SnO2 and Bi2S3@Sn 0.904 XPS fine spectra of O2, including (a) high-resolution XPS spectra of Sn3d, (b) high-resolution XPS spectra of S2p and Bi4f, (c) high-resolution XPS spectra of O 1s, and (d) high-resolution XPS spectra of C 1s.

[0030] Figure 8 :Bi2S3, Bi2S3@SnO2 and Bi2S3@Sn 0.904 O2 at 500 mA g -1 Cyclic performance at current density;

[0031] Figure 9 :Bi2S3, Bi2S3@SnO2 and Bi2S3@Sn 0.904 O2 rate performance at different current densities;

[0032] Figure 10 :Bi2S3@Sn 0.904 O2,Bi2S3@Sn 0.904 O2-1 and Bi2S3@Sn 0.904 O2-2 electrode material at 0.5 A g -1 Cyclic performance at current density;

[0033] Figure 11 :Bi2S3@Sn 0.904 O2 at 2.0 A g-1 Cyclic performance at current density;

[0034] Figure 12 : (a) Bi2S3, Bi2S3@SnO2 and Bi2S3@Sn 0.904 Impedance curves after O2 cycling, (b) Z' and ω at low frequencies -1 / 2 A graph showing the relationship between the curves. Detailed Implementation

[0035] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0036] As described in the background section, the synergistic effect of heterogeneous interfaces can also suppress the volume expansion and shedding of active materials, reducing capacity decay. Defect sites can enhance ion / electron transport, optimize reaction kinetics, improve material stability, and increase the number of active sites.

[0037] Based on this, the purpose of this invention is to provide a tin-bismuth bimetallic oxysulfide electrode material modified with anion and cation dual vacancy, its preparation method, and its application. This invention innovatively utilizes Bi₂S₃ nanorods as a template matrix to prepare Bi₂S₃@SnS₂ via a hydrothermal reaction. The regulator TAA effectively controls the morphology of the nanomaterial, resulting in a material with a regular morphology and uniformly distributed surface-loaded particles. Although calcination is carried out in argon, the oxygen carried by the surfactant polyvinylpyrrolidone in the precursor is sufficient to convert SnS₂ to SnO₂. Furthermore, calcination at 550°C partially decomposes Bi₂S₃ to generate elemental Bi, simultaneously generating sulfur vacancies. The elemental Bi then catalyzes the reverse formation of tin cation vacancies Sn from SnO₂. 0.904 O2 can simultaneously introduce sulfur and tin vacancies and concurrently construct Sn. 0.904 O2-Bi2S3 heterostructure. Bi2S3@SnS2 is transformed into Bi2S3@Sn 0.904 O2 and Bi2S3 nanorods, acting as the core, effectively mitigate volume expansion during energy storage in electrode materials due to the inherent stable structure of bismuth-based materials, while simultaneously providing a pathway for lithium-ion transport; Sn 0.904 O2, acting as a shell, offers more active sites and higher specific capacity due to its high theoretical specific capacity. The generation of tin cation vacancies can further improve the conductivity of the material, thereby enhancing its energy storage performance.

[0038] To enable those skilled in the art to better understand the technical solution of this application, the technical solution of this application will be described in detail below with reference to specific embodiments.

[0039] The test materials used in the embodiments of this invention are all conventional test materials in the art and can be purchased through commercial channels.

[0040] Example 1: Bi2S3@Sn 0.904 O2 preparation

[0041] (1) 0.48 g of bismuth nitrate pentahydrate (Bi(NO3)3•5H2O) and 0.63 g of thiourea (CH4N2S) were dissolved by ultrasonication in 20 mL of ethylene glycol (C2H6O2) until completely dissolved. The mixture was heated and stirred in an oil bath at 90 °C for 3 hours. The resulting black suspension was centrifuged and filtered. The precipitate was washed three times each with anhydrous ethanol and deionized water. After drying under vacuum at 60 °C, bismuth sulfide (Bi2S3) nanorods were obtained.

[0042] (2) Take 0.05 g of the bismuth sulfide nanorods prepared in step (1) and add them to a beaker containing 30 mL of deionized water. Stir and disperse for 20 minutes. Then add 0.045 g of stannous chloride dihydrate (SnCl2•2H2O), 0.25 g of thioacetamide (TAA), and 0.2 g of polyvinylpyrrolidone (PVP) in sequence. Stir until the mixture is homogeneous and continue to disperse by ultrasonication for 30 minutes. Then transfer it to a polytetrafluoroethylene-lined high-pressure reactor and carry out hydrothermal reaction at 200℃ for 12 hours. After the reaction is completed, collect the precipitate, wash it three times with water and ethanol in sequence, and then dry it at 60℃ for 12 hours to obtain solid powder Bi2S3@SnS2.

[0043] (3) The solid powder Bi2S3@SnS2 was placed in an argon (Ar) atmosphere and heated to 550℃ for 2 hours at a heating rate of 5℃ / min. After natural cooling to room temperature, Bi2S3@SnS2 was obtained. 0.904 O2.

[0044] Comparative Example 1

[0045] The difference from Example 1 is that TAA was not added. The final product was Bi2S3@SnO2.

[0046] Comparative Example 2

[0047] The difference from Example 1 is that the calcination temperature was 350℃. The final product obtained was Bi2S3@SnO2-350.

[0048] Comparative Example 3

[0049] The difference from Example 1 is that the calcination temperature was 650℃. The final product obtained was Bi2S3@SnO2-650.

[0050] Comparative Example 4

[0051] The difference from Example 1 is that the amount of stannous chloride dihydrate (SnCl2•2H2O) added is 0.086 g. The final product is Bi2S3@Sn. 0.904 O2-1.

[0052] Comparative Example 5

[0053] The difference from Example 1 is that the amount of stannous chloride dihydrate (SnCl2•2H2O) added is 0.0226 g. The final preparation yielded Bi2S3@Sn 0.904 O2-2.

[0054] Compared to Example 1, Comparative Examples 4 and 5 adjusted the molar ratio of Bi to Sn in bismuth sulfide nanorods and stannous chloride dihydrate. In Example 1, the molar ratio of Bi to Sn was 1:1; in Comparative Example 4, it was 1:2; and in Comparative Example 5, it was 2:1. By adjusting the molar ratio of Bi to Sn, not only were Bi₂S₃ and Sn present in the product... 0.904 The phase of the product varies depending on the proportion of O2.

[0055] Example 2: Characterization

[0056] The Bi2S3@SnS2 prepared in step (2) of Example 1, the Bi2S3@SnO2 prepared in Comparative Example 1, and the Bi2S3@SnO2 prepared in step (3) of Example 1 were analyzed using a Bruker D8 Advance X-ray diffractometer (Cu target, λ=1.5406Å). 0.904 O2, and Bi2S3@Sn prepared by comparative examples 4-5 0.904 O2-1 and Bi2S3@Sn 0.904 O2-2 was used for detection, and the corresponding XRD pattern was obtained. Comparison with the standard card revealed that... Figure 1 (a) and Figure 1 As can be seen in (b), Bi2S3@SnS2, Bi2S3@SnO2 and Bi2S3@Sn were successfully prepared. 0.904 O2. This indicates that heat treatment of Bi2S3@SnS2 successfully converts SnS2 to SnO2, with Bi2S3 partially decomposing into a small amount of elemental Bi. Simultaneously, Bi reverse-catalyzes the conversion of SnO2 to Sn. 0.904 O2 generates Sn cation vacancies. (From...) Figure 1 As can be seen in (c), compared to Bi2S3@SnO2, Bi2S3@Sn 0.904 The peak spectrum of O2 shifted due to the generation of Sn vacancies. Figure 1As can be seen in (d), Bi2S3@Sn prepared with different Bi:Sn molar ratios 0.904 O2-x exhibits different host phases Bi2S3 and Sn. 0.904 O2.

[0057] Figure 2 The XRD patterns of Bi2S3@SnO2-350 prepared in Comparative Example 2 and Bi2S3@SnO2-650 prepared in Comparative Example 3 are shown. The test conditions are the same as those for Bi2S3@SnO2-350 prepared in Comparative Example 2 and Bi2S3@SnO2-650 prepared in Comparative Example 3. Figure 1 The samples remained consistent. Comparison with the standard card revealed that... Figure 2 The Bi2S3@SnO2-350 spectrum shown in (a) contains both Bi2S3 and SnO2 phases, and the peak noise is relatively high, indicating that the Bi2S3@SnO2 intermediate obtained in Example 1 underwent a phase transformation at 350°C. However, its crystallinity is poor, and no elemental Bi was generated, which is unfavorable for catalytic generation of Sn vacancies. Figure 2 The Bi2S3@SnO2-650 shown in (b) contains Bi2S3, Bi, Sn, and SnO phases. Although elemental Bi is produced, elemental Sn and SnO phases are also generated. However, the excessively high temperature causes a significant phase transformation, making it impossible to guarantee the formation of Bi2S3-SnO. 0.904 Heterojunctions. The above results indicate that temperature has a significant impact on the construction of dual-vacancy anion-cation junctions.

[0058] The Bi2S3 prepared in step (1) of Example 1, the Bi2S3@SnO2 prepared in Comparative Example 1, and the Bi2S3@SnO2 prepared in step (3) of Example 1 were examined using a ZESSIS Sigma 300 field emission scanning electron microscope (SEM) and a Thermo Fisher Scientific Talos F200X S transmission electron microscope (TEM), respectively. 0.904 O2 was used to detect the microstructure and structure. Figure 3 As shown in the SEM image in (a), the Bi2S3 nanorods have a smooth surface and uniform size. Figure 3 In (b), the basic structure of Bi2S3@SnO2 obtained by hydrothermal treatment is also maintained as a nanorod structure, and the nanoparticles loaded on the surface are sparse, loose and unevenly distributed. Figure 3 Bi2S3@Sn in (c) 0.904 O2 also has a nanorod structure, but unlike other structures, its surface is uniformly loaded with nanoparticles and exhibits a wrinkled appearance. This is due to the formation of tin sulfide during the hydrothermal sulfidation process. Figure 3 (d) and Figure 3 The HRTEM image in (e) further reveals Bi2S3@SnO2 and Bi2S3@Sn 0.904The microstructure of O2 shows that the nanoparticles loaded on the Bi2S3@SnO2 surface are unevenly distributed, with some areas lacking loaded nanoparticles, while Bi2S3@Sn 0.904 O2 exhibits a uniform distribution of nanoparticles on the surface of nanorods. Figure 3 The high-resolution transmission electron microscopy results in (f) show that Bi2S3@Sn 0.904 O2 is composed of Bi2S3 and Sn 0.904 Composed of O2, it forms a uniform heterogeneous structure. This unique nanorod structure effectively enhances ion transport efficiency. The Bi2S3 core greatly alleviates the volume expansion during lithium storage in the electrode material. Sn 0.904 Using O2 as an outer shell can improve the specific capacity of electrode materials, while Sn vacancies can further enhance the specific capacity, and heterostructures can increase structural stability. The synergistic effect of cation vacancies and heterostructures can comprehensively improve the energy storage performance of electrode materials.

[0059] Figure 4 SEM images of the samples prepared in Comparative Example 2 and Comparative Example 3. Figure 4 (a) shows that the morphology and structure of the Bi2S3@SnO2-350 sample prepared at a calcination temperature of 350℃ are similar to those of Bi2S3@SnO2. 0.904 The O2 content is basically the same, both consisting of nanoparticles loaded on the surface of nanorods and exhibiting a wrinkled appearance. Figure 4 Figure (b) shows that when the calcination temperature is 650℃, the Bi2S3@SnO2-650 sample prepared exhibits a large amount of agglomeration and its structure becomes irregular. This indicates that the calcination temperature has a significant impact on the structure of nanomaterials.

[0060] The Bi2S3@Sn prepared in Example 1 was measured using the Super-XEDS spectrometer equipped with a Thermo Fisher Talos F200X S transmission electron microscope. 0.904 The elemental energy spectrum of O2, such as Figure 5 As shown, the test results indicate that Bi2S3@Sn 0.904 O2 contains Sn, Bi, S, O, N, and C elements, among which Sn, Bi, S, and O elements are distributed very evenly.

[0061] Detection of Bi2S3@Sn prepared in Example 1 using an EMXplus-10 / 12 spectrometer (Bruker) 0.904 The electron paramagnetic resonance (EPR) spectra of Bi2S3@SnO2 prepared by O2 and Comparative Example 1 are shown below. Figure 6 As shown, for Bi2S3@SnO2, its g value is 2.005, which corresponds to the presence of sulfur vacancies. Bi2S3@SnO2 prepared by heat treatment of Bi2S3@SnO2... 0.904The position of the O2, EPR signal shifted because SnS2 and Bi2S3 decomposed during the heat treatment process, resulting in the loss of some sulfur atoms and the creation of sulfur vacancies. (Bi2S3@Sn) 0.904 The increased EPR signal intensity of O2 indicates an increase in vacancy concentration. For Bi2S3@Sn 0.904 The EPR signal at O2, g = 2.004 can be attributed to sulfur vacancies. For Bi2S3@Sn 0.904 Based on the XRD and TEM test results above, this indicates that both Sn cation vacancies and sulfur anion vacancies exist in this material. The synergistic effect of Sn and sulfur vacancies will further provide more energy storage active sites, thereby improving the ion transport rate.

[0062] Figure 7 Bi2S3@Sn prepared in Example 1 0.904 High-resolution XPS spectra of Sn3d, S2p, Bi4f, O1s, and C1s of Bi2S3@SnO2 prepared by O2 and Comparative Example 1. Figure 7 As shown in (a), there are two peaks in Bi2S3@SnO2 at 486.7 eV and 495.1 eV, which correspond to Sn3d of SnO2, respectively. 3 / 2 and Sn3d 5 / 2 And Bi2S3@Sn 0.904 The peak spectrum corresponding to O2 shifts towards higher binding energies compared to Bi2S3@SnO2, indicating that in Bi2S3-Sn 0.904 Electron transfer occurred between O2 heterojunctions. Figure 7 In (b), Bi2S3@Sn is given. 0.904 The S2p and Bi4f energy spectra of O2 and Bi2S3@SnO2 show that, for Bi2S3@SnO2, the fitted peaks at 163.4 and 158.1 eV are attributed to the Bi4f peaks of Bi2S3, respectively. 5 / 2 and Bi 4f 7 / 2 The two shoulder peaks at 164.4 and 159.2 eV are likely due to the Bi-O bond formed between Bi₂S₃ and SnO₂. The fitted peaks at 160.7 and 162.0 eV are attributed to the S2p bonds of Bi₂S₃. 3 / 2 and S2p 1 / 2 Compared to Bi2S3@SnO2, in Bi2S3-Sn 0.904 Similarly, in O2, the energy spectrum shifts towards higher binding energies. This is because the concentration of tin cation vacancies is higher than that of sulfur anion vacancies. The generation of cation and anion vacancies disrupts the charge balance of the original crystal structure and changes the surrounding electron cloud density. Tin cation vacancies are more prevalent, which ultimately causes the peak spectrum to shift towards higher binding energies. Figure 7 (c) gives Bi2S3@Sn 0.904 The O1s spectra of O2 and Bi2S3@SnO2 show that, for Bi2S3@SnO2, the three peaks at 530.3 eV, 531.8 eV, and 533.3 eV can be attributed to Sn-O bonds, adsorbed oxygen, and CO-Sn bonds. In Bi2S3-Sn... 0.904 The peak spectrum in O2 also shifted towards higher binding energies, and the peak intensities changed, with increased Sn-O intensity, decreased adsorbed oxygen intensity, and decreased CO-Sn intensity. This indicates that during the calcination process, the chemical bonds changed when SnS2 was converted to SnO2, and the sulfur vacancy concentration increased. The C 1s energy spectrum in Figure 7(d) shows that in Bi2S3@Sn 0.904 Both O2 and Bi2S3@SnO2 contain C–C, C–O, and C=O bonds, while Bi2S3-Sn... 0.904 O2 also contains an additional OC=O bond (291.3 eV).

[0063] Test case

[0064] The Bi2S3 electrode material prepared in step (1) of Example 1, the Bi2S3@SnO2 electrode material prepared in Comparative Example 1, and the Bi2S3@SnO2 electrode material prepared in step (3) of Example 1 were compared. 0.904 Batteries made from O2 electrode materials were tested to compare the performance of different electrode materials.

[0065] The specific steps are as follows: Add 80% of the three electrode materials mentioned above, 10% of acetylene black, and 10% of polyvinylidene fluoride to N-methyl-2-pyrrolidine (NMP) according to the mass ratio to obtain an electrode slurry, ideally with a just-flowable consistency. Use a coater to evenly coat the electrode slurry onto copper foil cleaned with alcohol, and after pre-drying, vacuum dry it at 110°C for 12 hours in a vacuum oven. Use this as the negative electrode for LIBs (denoted as Bi2S3 electrode, Bi2S3@SnO2 electrode, and Bi2S3@SnO2 electrode, respectively). 0.904O2 electrode). A 1M LiPF6 solution (obtained by dissolving LiPF6 in the organic solvents ethylene carbonate (EC), dimethyl carbonate (DMC), and ethyl methyl carbonate (EMC) in a mass ratio of 1:1:1, containing 2.0% FEC) was used as the electrolyte, a polypropylene membrane (Celgard 2320) as the separator, and a pure lithium metal sheet as the counter electrode. 2032-type button cells were assembled using metal springs and gaskets in a glove box filled with an Ar atmosphere (oxygen and moisture less than 1 ppm). Cyclic performance, rate performance, and high-rate long-cycle performance were measured using a NEWARE battery measurement system, and the specific capacity was calculated based on the total mass of the active materials, with a cutoff voltage range of 3V to 0.01V. Electrochemical impedance spectroscopy was performed using a CHI760D electrochemical workstation, with a frequency range of 100 kHz to 0.01 Hz and an amplitude of 5 mV.

[0066] Figure 8 for Bi2S3, Bi2S3@SnO2 and Bi2S3@Sn 0.904 O2 electrode material at 0.5 A g -1 Cyclic performance at current density. At 0.5 A g -1 At current density, Bi2S3@Sn 0.904 After 150 cycles, the O2 electrode maintained a stable capacity of 737.3 mAh g. -1 In comparison, the discharge capacities of the Bi2S3 electrode and the Bi2S3@SnO2 electrode after 150 cycles were 126.3 mAh g⁻¹. -1 and 330.2 mA hg -1 In contrast, Bi2S3@Sn 0.904 The O2 electrode is superior in terms of specific capacity and stability.

[0067] Figure 9 for Bi2S3, Bi2S3@SnO2 and Bi2S3@Sn 0.904 Rate performance diagram of LIBs anode made of O2 electrode material, when the current density is 0.2 A g -1 0.5 A g -1 1.0 A g -1 2.0 Ag -1 and 5.0 A g -1 At that time, Bi2S3@Sn 0.904 The O2 electrode can maintain 900.1 mA hg. -1 793.5 mA hg -1 711.2 mA hg -1 610.8 mA hg-1 and 435.0 mA hg -1 The average reversible capacity is significantly better than that of Bi₂S₃ and Bi₂S₃@SnO₂ electrode materials. In particular, Bi₂S₃@SnO₂… 0.904 The O2 electrode significantly outperforms the Bi2S3 and Bi2S3@SnO2 electrodes in high-rate performance. The Bi2S3 and Bi2S3@SnO2 electrodes at 5.0 A g... -1 The capacity contribution at these current densities is minimal, at 138.8 and 210.1 mA hg, respectively. -1 When the current density recovers to 0.2 A g -1 At that time, Bi2S3@Sn 0.904 O2 can still be maintained at 823.2 mA hg -1 The capacity indicates that it possesses excellent rate performance. The above results demonstrate the synergistic effect of tin cation vacancies and sulfur anion vacancies in Bi2S3-Sn. 0.904 O2 heterojunction modification strategy can effectively improve the lithium storage performance of electrode materials.

[0068] Figure 10 Bi2S3@Sn prepared according to specific example 1 0.904 O2 electrode material and Bi2S3@Sn prepared in Comparative Examples 4 and 5 0.904 O2-1 and Bi2S3@Sn 0.904 O2-2 electrode material at 0.5 A g -1 Cyclic performance at current density. At 0.5 A g -1 At current density, Bi2S3@Sn 0.904 After 150 cycles, the O2 electrode capacity stabilized at 737.3 mA hg. -1 In contrast, Bi2S3@Sn 0.904 O2-1 and Bi2S3@Sn 0.904 The discharge capacity of the O2-2 electrode after 150 cycles was 636.1 mA hg. -1 and 275.5 mA hg -1 And Bi2S3@Sn 0.904 O2-1 and Bi2S3@Sn 0.904 The O2-2 electrode exhibits a lower initial reversible capacity. This demonstrates that appropriately controlling the Bi and Sn ratio is crucial for improving the specific capacity and stability of electrode materials.

[0069] Figure 11 Bi2S3@Sn prepared according to specific example 1 0.904The long-cycle performance diagram of the LIBs anode made of O2 electrode material is shown in the figure. From the figure, we can see the performance of Bi2S3@Sn. 0.904 O2 at 2.0 A g -1 It can stably cycle for 1500 cycles at current density, maintaining a capacity of 656.8 mA hg. -1 The above results indicate that the Bi2S3@Sn prepared by the anion-cation dual-vacancy synergistic heterojunction modification strategy... 0.904 O2 electrode materials exhibit excellent cycling performance in lithium storage. Bi2S3@Sn 0.904 The high specific capacity and excellent cycling stability of the O2 electrode are attributed to Bi2S3 and Sn. 0.904 The construction of the O2 heterostructure and the introduction of tin cation and sulfur anion vacancies played a crucial role in stabilizing the electrode structure, increasing active sites, and improving lithium-ion transport efficiency. The synergistic effect of the heterojunction and the dual cation / anion vacancies significantly enhanced the electrode structure.

[0070] Figure 12 for Bi2S3, Bi2S3@SnS2 and Bi2S3@Sn 0.904 LIBs anodes made of O2 electrode material at 0.5 A g -1 EIS impedance spectrum after 150 cycles at current density and corresponding Z' and ω in the low-frequency region -1 / 2 A graph showing the relationship between the curves. Figure 12 The EIS impedance curve shown in (a) illustrates the Bi2S3@Sn after cycling. 0.904 The O2 electrode exhibits a semicircular ring with minimum impedance, indicating that the charge transfer resistance is minimal during charging and discharging. Figure 12 Z' and ω shown in (b) -1 / 2 The curve relationship graph shows that Bi2S3@Sn 0.904 The slope of the fitting curve for the O2 electrode is 93, which is much smaller than the slope of 478 for Bi2S3 and 183 for Bi2S3@SnO2. Based on the negative correlation between the ion diffusion coefficient and the slope value, it can be concluded that Bi2S3@Sn... 0.904 The O2 electrode exhibits the fastest ion diffusion rate. This is attributed to the fact that the synergistic heterostructure of tin cation vacancies and sulfur anion vacancies effectively enhances the structural stability of the electrode material and reduces the ion transport barrier.

[0071] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. An anion-cation double-vacancy modified tin-bismuth double-metal oxysulfide electrode material, characterized in that, The tin-bismuth bimetallic oxysulfide electrode material is Bi2S3@Sn 0.904 O2 heterojunction, Sn 0.904 O2 nanoparticles are loaded on Bi2S3 nanorods; the Bi2S3 nanorods contain sulfur anion vacancies, and the Sn 0.904 O2 nanoparticles contain tin cation vacancies; The anion-cation dual-vacancy modified tin-bismuth bimetal oxysulfide electrode material is prepared by the following method: (1) dispersing bismuth sulfide nanorods into deionized water, then sequentially adding tin salt, thioacetamide and polyvinylpyrrolidone and mixing uniformly, then performing hydrothermal reaction, collecting the product, washing, drying to obtain a solid powder; (2) calcining the solid powder under a protective atmosphere to obtain the anion-cation dual-vacancy modified tin-bismuth bimetal oxysulfide electrode material; the calcination temperature is 550 ℃, and the time is 2-3 h.

2. The tin-bismuth bimetallo-oxysulfide electrode material of claim 1, wherein, In step (1), the bismuth sulfide nanorods are prepared by the following method: Dissolving bismuth salt and sulfide in ethylene glycol, heating and stirring under an oil bath to obtain a black suspension, then sequentially performing filtration, washing, drying to obtain bismuth sulfide Bi2S3 nanorods.

3. The tin-bismuth bimetallo-oxysulfide electrode material of claim 2, wherein, The bismuth salt is Bi(NO3)3•5H2O or BiCl3; the sulfide is thiourea or thioacetamide; the temperature of the oil bath is 80-110 ℃, and the time is 2-4 h.

4. The tin-bismuth bimetallo-oxysulfide electrode material of claim 1, wherein, In step (1), the tin salt is SnCl2•2H2O; the mass ratio of the bismuth sulfide nanorods, SnCl2•2H2O, thioacetamide and polyvinylpyrrolidone is 5:2.5-7:20-30:15-25.

5. The tin-bismuth bimetallo-oxysulfide electrode material of claim 1, wherein, In step (1), the uniform mixing is stirring until uniform followed by ultrasonic dispersion for 30 min; the drying temperature is 60-80 ℃, and the time is 8-12 h.

6. The tin-bismuth bimetallo-oxysulfide electrode material of claim 1, wherein, In step (1), the hydrothermal reaction temperature is 180-200 ℃, and the time is 12 h.

7. Use of the tin-bismuth bimetal oxysulfide electrode material of any one of claims 1-6 in improving the performance of lithium ion batteries.

8. Use according to claim 7, characterized in that, The improvement of the performance of lithium ion batteries includes improving the conductivity, energy storage, specific capacity, stability, lithium ion transmission efficiency, and reducing the ion transmission barrier.

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