A method for optimizing bismuth sulfide-based lithium battery negative electrode materials using multilayer interface construction

Abstract

The present invention relates to a method for optimizing bismuth sulfide-based lithium battery negative electrode materials by utilizing a multi-layer interface construction, and belongs to the technical field of lithium-ion battery negative electrodes. The present invention uses a hydrothermal reaction to prepare a precursor Bi2S3 according to the molar ratio of Bi2S3, uses the precursor Bi2S3 as a core, and glucose as a carbon source, and prepares a precursor Bi2S3@C through a hydrothermal reaction and heat treatment. The precursor Bi2S3@C is sensitized and activated and electrolessly plated with metal X to obtain a precursor Bi2S3@C@X. The precursor Bi2S3@C@X is used as a core to prepare a PPy-coated precursor Bi2S3@C@X@PPy, and then carbonized to obtain a multi-layer interface bismuth sulfide-based lithium battery negative electrode material Bi2S3@C@X@C. PPy The bismuth sulfide-based negative electrode material constructed by the present invention through multiple interfaces has high theoretical specific capacity, rate performance and stable cycle performance.

Description

Technical Field

[0001] The invention relates to a method for optimizing bismuth sulfide-based lithium battery negative electrode materials by utilizing a multilayer interface construction, and belongs to the technical field of lithium ion battery negative electrodes. Background Art

[0002] Lithium-ion batteries have the advantages of high energy density, long cycle life and low self-discharge characteristics. They are currently widely used in various devices such as various power tools, stationary storage devices, uninterruptible power supply devices and electric vehicles. The progress and achievements of lithium-ion batteries in an increasingly wide range of applications have led to higher and higher requirements for their energy density. In order to achieve this goal, there is an urgent need for continuous innovation of batteries and development of advanced materials to achieve lithium-ion battery negative electrode materials with high energy density and long life, which has a decisive influence on the performance of lithium-ion batteries. Carbon materials mainly based on graphite are the most commonly used negative electrode materials in commercial lithium-ion batteries due to their advantages such as low working potential, low cost and long cycle life. However, the theoretical specific capacity of graphite negative electrode is low, generally reaching 372mAhg -1 , which cannot meet the current demand for high performance, especially high energy density lithium-ion batteries.

[0003] Bismuth sulfide-based negative electrode materials have a simple preparation process and low preparation cost. At the same time, they have a high theoretical specific capacity (625mAhg -1 ), has received widespread attention as a negative electrode material in recent years. However, bismuth sulfide material has always been a wide-bandgap semiconductor material with a bandgap of 1.3 to 1.7 eV. It is a typical semiconductor conductive material. The generation of electrons mainly relies on thermal excitation. The electron concentration itself is very low at room temperature, and the conductivity is poor. At the same time, the sulfur element will dissolve and lose in the organic electrolyte. When the conversion and alloying reactions occur during the discharge process, the volume will expand significantly. The large volume expansion makes it easy to cause the material structure to collapse during the lithium insertion / delithiation process, which causes cracks and breakage of the powder particles, and ultimately leads to the problem of continuous capacity decay in the sample. Therefore, although bismuth sulfide material has great potential as a negative electrode for lithium-ion batteries, due to low conductivity and large volume expansion problems, its cycle performance and rate performance are poor, which limits its application range. Summary of the Invention

[0004] In response to the problem that the existing bismuth sulfide negative electrode materials have low electrical conductivity and volume expansion during charging and discharging, resulting in a significant decrease in capacity, the present invention proposes a method for optimizing bismuth sulfide-based lithium battery negative electrode materials by using multilayer interface construction. That is, the electronic conductivity and ion transport performance of the negative electrode material are improved by multilayer interface construction, thereby increasing its capacity while improving the capacity retention rate, thereby achieving optimization of the bismuth sulfide negative electrode material.

[0005] The present invention adopts a hydrothermal reaction to prepare a precursor Bi2S3 according to the molar ratio of Bi2S3, takes the precursor Bi2S3 as a core and glucose as a carbon source, and prepares a precursor Bi2S3@C through hydrothermal reaction and heat treatment. The precursor Bi2S3@C is sensitized and activated and chemically plated with metal X to obtain a precursor Bi2S3@C@X. The precursor Bi2S3@C@X is used as a core to prepare a PPy-coated precursor Bi2S3@C@X@PPy, and then carbonized to obtain a multi-layer interface bismuth sulfide-based lithium battery negative electrode material Bi2S3@C@X@C. PPy The bismuth sulfide-based negative electrode material constructed by the present invention through multiple interfaces has high theoretical specific capacity, rate performance and stable cycle performance.

[0006] A method for optimizing bismuth sulfide-based lithium battery negative electrode materials by utilizing multilayer interface construction, comprising the following steps:

[0007] (1) According to the molar ratio of Bi2S3, bismuth nitrate pentahydrate and thiourea are dissolved in ultrapure water, thioglycolic acid is added, and then hydrothermal reaction is carried out, solid-liquid separation is carried out, and the solid is washed and dried to obtain the precursor Bi2S3;

[0008] (2) Dispersing the precursor Bi2S3 in ultrapure water to obtain a Bi2S3 dispersion, adding glucose and stirring to dissolve, then performing a hydrothermal reaction, cooling and standing, removing the supernatant, drying, and subjecting the mixture to a heat treatment under anaerobic conditions to obtain the precursor Bi2S3@C;

[0009] (3) sensitizing and activating the precursor Bi2S3@C, electrolessly plating the activated precursor Bi2S3@C with metal X, and vacuum drying to obtain the precursor Bi2S3@C@X, wherein the metal is Sn, Ni, Al, Sb, Ge, Mg or Zn;

[0010] (4) Dispersing the precursor Bi2S3@C@X and polypyrrole in ultrapure water and stirring until the ultrapure water is completely evaporated to obtain the precursor Bi2S3@C@X@PPy;

[0011] (5) The precursor Bi2S3@C@X@PPy is carbonized under oxygen-free conditions to obtain a multilayer interface bismuth sulfide-based lithium battery negative electrode material Bi2S3@C@X@C PPy .

[0012] The hydrothermal reaction temperature in step (1) is 120-180° C., and the reaction time is 10-18 hours.

[0013] The concentration of the Bi2S3 dispersion in step (2) is 0.5-1 g / 100 mL, the mass ratio of glucose to the precursor Bi2S3 is 2-4:3, the hydrothermal reaction temperature is 150-180°C, the time is 10-15 h, and the heat treatment temperature is 300-500°C, and the time is 3-5 h.

[0014] The sensitizing solution in step (3) is a SnCl2-HCl solution, wherein the SnCl2 concentration in the SnCl2-HCl solution is 10-g / L and the HCl concentration is 1-2 mol / L; the solid-liquid ratio (g:mL) of the precursor Bi2S3@C to the sensitizing solution is 0.5-1:50, and the sensitization time is 5-10 min.

[0015] The activation solution in step (3) is an AgNO3-ammonia solution, the AgNO3 concentration in the activation solution is 0.1-0.2 g / L, and the pH value is 4-5; the solid-liquid ratio g:mL of the precursor Bi2S3@C and the activation solution is 0.5-1:50, and the activation time is 5-8 min.

[0016] The chemical plating solution in step (3) contains metal salt X, reducing agent NaH2PO2·H2O, complexing agent C6H8O7, buffer sodium acetate, accelerator C4H6O4 and surfactant, the pH value of the chemical plating solution is 4-4.8, the chemical plating temperature is 60-90°C, and the time is 4-5h.

[0017] The concentration of the metal salt X in the chemical plating solution is 20-30 g / L, the concentration of the reducing agent NaH2PO2·H2O is 25-35 g / L, the concentration of the complexing agent C6H8O7 is 20-30 g / L, the concentration of the buffering agent sodium acetate is 8-10 g / L, the concentration of the accelerator C4H6O4 is 7-10 g / L, and the concentration of the surfactant C 12 H 25 The concentration of NaO3S is 3-5 mg / L.

[0018] In the step (4), the mass ratio of polypyrrole to the precursor Bi2S3@C@X is 1 to 5:100.

[0019] The carbonization temperature in step (5) is 400-500° C. and the time is 3-5 hours.

[0020] The present invention obtains a precursor Bi2S3@C by coating bismuth sulfide material with carbon, which can improve the electrical conductivity of the material and suppress the capacity decay problem of the bismuth sulfide material during the charge and discharge process; a metal X layer is plated on the surface of the precursor Bi2S3@C by chemical plating to obtain the precursor Bi2S3@C@X. The metal X layer greatly improves the electrical conductivity of the material and provides a high-speed transport channel for electrons and ions. At the same time, it is more conducive to the embedding of lithium ions during battery discharge, forming an alloy material, and significantly improving the lithium storage performance of the material; C formed by carbonization of PPy PPyCoating can alleviate the capacity attenuation caused by volume expansion during the charge and discharge process of the material, inhibit the large volume expansion of the alloy material, and improve the cycle stability of the battery; PPy itself has a high electrical conductivity and is also a C, N five-membered heterocyclic molecule. After carbonization, PPy can achieve N element self-doping, further improving the electrical conductivity of the material.

[0021] The beneficial effects of the present invention are:

[0022] (1) The present invention prepares Bi2S3 nanopowders with good crystallinity through a hydrothermal reaction, and thioglycolic acid is beneficial for regulating the microstructure of the nanopowders;

[0023] (2) The present invention coats the surface of the precursor Bi2S3 with a glucose solution, and then carbonizes the glucose by high-temperature heat treatment to obtain a carbon-coated precursor Bi2S3@C powder. The coated carbon can improve the electron mobility of the material and suppress the volume change of the material during charging.

[0024] (3) The present invention obtains the precursor Bi2S3@C@X by chemically plating a layer of active metal that can react with lithium on the surface of the precursor Bi2S3@C powder, which not only helps to improve the conductivity of the material, but also forms an alloy during battery discharge to improve the storage capacity of lithium, which helps to improve the battery capacity;

[0025] (4) The present invention forms C by carbonization of PPy PPy The coating layer can inhibit the volume expansion of the material during the charge and discharge process. At the same time, after carbonization, PPy can realize the self-doping effect of N elements, further improving the electrical conductivity of the material, so that the bismuth sulfide-based negative electrode material has a more stable cycle performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The negative electrode material Bi2S3@C@X@C in Example 1 PPy Low-magnification SEM image of

[0027] Figure 2 The negative electrode material Bi2S3@C@X@C in Example 1 PPy High magnification SEM image of

[0028] Figure 3 This is a low-magnification SEM image of pure Bi2S3 in comparative example 7;

[0029] Figure 4 Bi2S3@C@X@C in Example 1 PPy Cycle performance diagram;

[0030] Figure 5 Bi2S3@C@X@C in Comparative Example 6 PPy Cycle performance diagram;

[0031] Figure 6 This is the cycle performance diagram of pure Bi2S3 in comparative example 7. DETAILED DESCRIPTION

[0032] The present invention will be further described in detail below in conjunction with specific embodiments, but the protection scope of the present invention is not limited to the contents described above.

[0033] Summary of the Invention

[0034] The present invention obtains a precursor Bi2S3@C by coating bismuth sulfide material with carbon, which can improve the electrical conductivity of the material and suppress the capacity decay problem of the bismuth sulfide material during the charge and discharge process; a metal X layer is plated on the surface of the precursor Bi2S3@C by chemical plating to obtain the precursor Bi2S3@C@X. The metal X layer greatly improves the electrical conductivity of the material and provides a high-speed transport channel for electrons and ions. At the same time, it is more conducive to the embedding of lithium ions during battery discharge, forming an alloy material, and significantly improving the lithium storage performance of the material; C formed by carbonization of PPy PPy Coating can alleviate the capacity attenuation caused by volume expansion during the charge and discharge process of the material, inhibit the large volume expansion of the alloy material, and improve the cycle stability of the battery;

[0035] The specific plan is:

[0036] A method for optimizing bismuth sulfide-based lithium battery negative electrode materials by utilizing multilayer interface construction, comprising the following steps:

[0037] (1) According to the molar ratio of Bi2S3, bismuth nitrate pentahydrate and thiourea are dissolved in ultrapure water, thioglycolic acid is added and stirred at a temperature of 80-100°C for 5 minutes, and then placed in a hydrothermal reaction at a temperature of 120-180°C for 10-18 hours. The solid-liquid separation is carried out, and the solid is washed and dried to obtain the precursor Bi2S3;

[0038] (2) The precursor Bi2S3 is dispersed in ultrapure water to obtain a Bi2S3 dispersion, glucose is added and stirred to dissolve, and then a hydrothermal reaction is carried out at a temperature of 150-180°C for 10-15 hours. The mixture is cooled and allowed to stand, the supernatant is removed, and the mixture is dried and heat-treated in an oxygen-free environment at a temperature of 300-500°C for 3-5 hours to obtain a precursor Bi2S3@C; the concentration of the Bi2S3 dispersion is 0.5-1 g / 100 mL, and the mass ratio of glucose to the precursor Bi2S3 is 2-4:3;

[0039] (3) The precursor Bi2S3@C is subjected to sensitization and activation treatment, and the activated precursor Bi2S3@C is subjected to chemical plating of metal X and vacuum drying to obtain the precursor Bi2S3@C@X, wherein the metal X is Sn, Ni, Al, Sb, Ge, Mg or Zn; the sensitizing solution is a SnCl2-HCl solution, the SnCl2 concentration in the SnCl2-HCl solution is 8-10 g / L, and the HCl concentration is 1-2 mol / L; the solid-liquid ratio of the precursor Bi2S3@C to the sensitizing solution is g:mL 0.5-1:50, and the sensitization time is 5-10 min; the activation solution is an AgNO3-ammonia solution, the AgNO3 concentration in the activation solution is 0.1-0.2 g / L, and the pH value is 4-5; the precursor Bi The solid-liquid ratio of 2S3@C to the activation solution is 0.5 to 1:50 g:mL, and the activation time is 5 to 8 minutes. The chemical plating solution contains a metal salt X, a reducing agent NaH2PO2·H2O, a complexing agent C6H8O7, a buffer sodium acetate, an accelerator C4H6O4, and a surfactant. The pH value of the chemical plating solution is 4 to 4.8, the chemical plating temperature is 60 to 90°C, and the time is 4 to 5 hours. The concentration of the metal salt X in the chemical plating solution is 20 to 30 g / L, the concentration of the reducing agent NaH2PO2·H2O is 25 to 35 g / L, the concentration of the complexing agent C6H8O7 is 20 to 30 g / L, the concentration of the buffer sodium acetate is 8 to 10 g / L, the concentration of the accelerator C4H6O4 is 7 to 10 g / L, and the surfactant C 12 H 25 NaO3S concentration is 3-5 mg / L;

[0040] (4) Dispersing the precursor Bi2S3@C@X and polypyrrole in ultrapure water and stirring until the ultrapure water is completely evaporated to obtain the precursor Bi2S3@C@X@PPy; the mass ratio of polypyrrole to the precursor Bi2S3@C@X is 1 to 5:100;

[0041] (5) The precursor Bi2S3@C@X@PPy is carbonized at 400-500℃ for 3-5h under oxygen-free conditions to obtain a multilayer interface bismuth sulfide-based lithium battery negative electrode material Bi2S3@C@X@C PPy .

[0042] Example 1: A method for optimizing bismuth sulfide-based lithium battery negative electrode materials using multilayer interface construction, the specific steps are as follows:

[0043] (1) Preparation of Bi2S3 precursor: 3 g of bismuth nitrate pentahydrate and 0.7 g of thiourea were weighed and dissolved in 70 ml of deionized water. 1 ml of thioglycolic acid was added and stirred at 60°C and 500 rpm for 5 min. The mixture was then transferred to a hydrothermal reactor and hydrothermally reacted at 140°C for 12 h to obtain a mixed solution. The mixed solution was centrifuged at 3000 rpm for 3 min, washed more than 3 times, and dried at 70°C for 12 h to obtain the Bi2S3 precursor.

[0044] (2) Preparation of Bi2S3@C precursor: 0.3 g of Bi2S3 precursor was weighed and dispersed in 40 ml of ultrapure water. 0.3 g of glucose was added and stirred for 60 min. After standing, the supernatant was removed and dried at 80 °C for 12 h. The precursor Bi2S3@C was obtained by uniformly heating to 400 °C under a nitrogen atmosphere and heat treating for 4 h.

[0045] (3) Preparation of Bi2S3@C@Sn precursor: 0.2 g of Bi2S3@C precursor was weighed and sensitized and activated. The activated Bi2S3@C precursor was electrolessly plated with Sn and vacuum dried to obtain Bi2S3@C@Sn precursor. The sensitizing solution was a SnCl2-HCl solution with a SnCl2 concentration of 10 g / L and a HCl concentration of 1 mol / L. The solid-liquid ratio of Bi2S3@C precursor to the sensitizing solution was 0.5:50 g:mL, and the sensitization time was 10 min. The activation solution was an AgNO3-ammonia solution with a AgNO3 concentration of 0.1 g / L and a pH of 4. The solid-liquid ratio of Bi2S3@C precursor to the activation solution was 0.5:50 g:mL, and the activation time was 5 min. The electroless plating solution contained 30 g / L of SnCl2 metal salt and 1 mol / L of reducing agent NaH2PO2·H2O. 35g / L, complexing agent C6H8O730g / L, buffer sodium acetate 10g / L, accelerator C4H6O4 10g / L and surfactant C 12 H 25 NaO3S 5mg / L, pH value of chemical plating solution is 4.8, temperature of chemical plating is 90℃, and time is 5h;

[0046] (4) Preparation of Bi2S3@C@Sn@PPy precursor: 0.2 g of Bi2S3@C@Sn and polypyrrole were dispersed in 20 ml of ultrapure water and stirred at 80°C until the ultrapure water was completely evaporated to obtain Bi2S3@C@Sn@PPy precursor; the mass ratio of polypyrrole to Bi2S3@C@Sn was 3:100;

[0047] (5) Negative electrode material Bi2S3@C@Sn@C PPyPreparation: 0.3 g of the precursor Bi2S3@C@Sn@PPy was placed in a glass boat, and the temperature was uniformly increased to 500°C at a heating rate of 5°C / min under a nitrogen atmosphere and carbonized for 3 h to obtain a multilayer interface bismuth sulfide-based lithium battery negative electrode material Bi2S3@C@Sn@C PPy ;

[0048] The preparation methods of the multilayer interface bismuth sulfide-based lithium battery negative electrode materials of Examples 2 to 6 are basically the same as the preparation method of the multilayer interface bismuth sulfide-based lithium battery negative electrode material of Example 1, except that the process parameters are as shown in Table 1.

[0049] Table 1 Preparation process parameters of multilayer interface bismuth sulfide-based lithium battery negative electrode materials of Examples 1 to 6

[0050]

[0051]

[0052] Ten groups of comparative examples were set up for experimental comparison with the multilayer interface bismuth sulfide-based lithium battery negative electrode materials provided in Examples 1-6. The process parameters of Comparative Examples 1-6 are shown in Table 2:

[0053] Table 2 Process parameters of Comparative Examples 1-6

[0054]

[0055] Comparative Examples 7 to 10 are illustrated using pure Bi2S3 without any coating treatment and the Bi2S3 of Example 1, Example 3, and Example 5 as examples. Comparative Example 7 is pure Bi2S3 without any coating treatment; Comparative Example 8 is a mixture of a pure Bi2S3 sample without any coating treatment and the Bi2S3 of Example 1, and the weight ratio of pure Bi2S3 without any coating treatment to the Bi2S3 of Example 1 is the same as that of pure Example 1; Comparative Example 9 is a mixture of a pure Bi2S3 sample without any coating treatment and the Bi2S3 of Example 3, and the weight ratio of pure Bi2S3 without any coating treatment to the Bi2S3 of Example 3 is the same as that of pure Example 3; Comparative Example 10 is a mixture of a pure Bi2S3 sample without any coating treatment and the Bi2S3 of Example 5, and the weight ratio of pure Bi2S3 without any coating treatment to the Bi2S3 of Example 5 is the same as that of pure Example 5;

[0056] The following tests were conducted using the lithium battery negative electrode materials provided in Examples 1-6 and Comparative Examples 1-10:

[0057] SEM characterization:

[0058] The negative electrode material Bi2S3@C@X@C in Example 1 PPy The SEM images are as follows Figures 1-2 As shown, at the micron-level resolution, the powder is clearly sea urchin-shaped; at the nanometer level, each sea urchin-shaped morphology is composed of countless nanorods, and there are obvious metal particles on the powder surface; the morphologies prepared in Examples 2 to 6 are basically the same as those in Example 1, and are sea urchin-like nanostructures;

[0059] The SEM image of pure Bi2S3 in comparative example 7 is as follows Figure 3 As shown, at the micron level, the powder is flower-shaped; at the nanometer level, each petal is composed of countless nanorods, which is significantly different from the morphology of Example 1.

[0060] Electrochemical performance characterization:

[0061] The powder materials obtained in Examples 1 to 6 and Comparative Examples 1 to 10 were assembled into button cells and -1 The charge and discharge test and the cycle stability test were carried out under constant current conditions; the preparation process of the CR2025 button battery was as follows: the lithium-ion battery was assembled in a sealed glove box filled with argon, and the water content and oxygen content were controlled below 0.1 ppm; a homemade disc electrode with a diameter of 12 mm (the material of the embodiment or comparative example) was used as the negative electrode, a Celgard2400 with a diameter of 17 mm was used as the diaphragm, a pure lithium sheet was used as the positive electrode, and the electrolyte solute was 1 mol L -1 The LiPF6 was prepared by mixing ethylene carbonate (EC), dimethyl carbonate (DMC) and ethyl methyl carbonate (EMC) in a volume ratio of 1:1:1. A tablet press was used for battery packaging. After the assembled battery was allowed to stand for 24 hours, an electrochemical test was performed.

[0062] Taking the Bi2S3 negative electrode materials prepared in Example 1 and Comparative Examples 6-7 as an example, the test results of the first charge and discharge and 15 cycles are as follows: Figures 4-6 The initial charge and discharge results and the capacity results after 15 cycles of Examples 1 to 6 and Comparative Examples 1 to 10 are shown in Table 3;

[0063] Table 3 Battery performance of Examples 1 to 6 and Comparative Examples 1 to 10

[0064]

[0065]

[0066] As can be seen from Table 3, the introduction of active metal particles in the multi-layer interface-coated Bi2S3 negative electrode materials of Examples 1 to 6 can promote the fixation of lithium ions during the charge and discharge process, and improve the lithium storage performance of the material. At the same time, the inner carbon layer can relieve the volume stress of the material to the greatest extent during the charge and discharge process, and reduce the migration distance of lithium ions, thereby improving the cycle stability of the material. After carbonization, the outermost layer of PPy can not only improve the conductivity of the negative electrode material, but also improve the stability of the overall structure of the material, improve the material's capacity attenuation caused by the volume expansion problem during the lithium storage process, and thus improve the material capacity and improve the capacity retention rate.

[0067] The above describes the specific embodiments of the present invention in detail, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in this field without departing from the scope of the present invention.

Claims

1. A method for optimizing bismuth sulfide-based lithium battery negative electrode materials by using multilayer interface construction, characterized in that: The specific steps are as follows: (1) According to the molar ratio of Bi2S3, bismuth nitrate pentahydrate and thiourea are dissolved in ultrapure water, thioglycolic acid is added, and then hydrothermal reaction is carried out, solid-liquid separation is carried out, and the solid is washed and dried to obtain the precursor Bi2S3; (2) Dispersing the precursor Bi2S3 in ultrapure water to obtain a Bi2S3 dispersion, adding glucose and stirring to dissolve, then performing a hydrothermal reaction, cooling and standing, removing the supernatant, drying, and subjecting the mixture to a heat treatment under anaerobic conditions to obtain the precursor Bi2S3@C; (3) sensitizing and activating the precursor Bi2S3@C, electrolessly plating the activated precursor Bi2S3@C with metal X, and vacuum drying to obtain the precursor Bi2S3@C@X, wherein the metal X is Sn, Ni, Al, Sb, Ge, Mg or Zn; (4) Dispersing the precursor Bi2S3@C@X and polypyrrole in ultrapure water and stirring until the ultrapure water is completely evaporated to obtain the precursor Bi2S3@C@X@PPy; (5) The precursor Bi2S3@C@X@PPy is carbonized under oxygen-free conditions to obtain a multilayer interface bismuth sulfide-based lithium battery negative electrode material Bi2S3@C@X@C PPy .

2. The method for optimizing bismuth sulfide-based lithium battery negative electrode materials by utilizing multilayer interface construction according to claim 1, characterized in that: The hydrothermal reaction temperature in step (1) is 120-180° C., and the reaction time is 10-18 hours.

3. The method for optimizing bismuth sulfide-based lithium battery negative electrode materials by utilizing multilayer interface construction according to claim 1, characterized in that: Step (2) The concentration of the Bi2S3 dispersion is 0.5-1 g / 100 mL, the mass ratio of glucose to the precursor Bi2S3 is 2-4:3, the hydrothermal reaction temperature is 150-180°C, the time is 10-15 h, and the heat treatment temperature is 300-500°C, and the time is 3-5 h.

4. The method for optimizing bismuth sulfide-based lithium battery negative electrode materials by utilizing multilayer interface construction according to claim 1, characterized in that: The sensitizing solution in step (3) is a SnCl2-HCl solution, wherein the SnCl2 concentration in the SnCl2-HCl solution is 8-10 g / L and the HCl concentration is 1-2 mol / L; the solid-liquid ratio g:mL of the precursor Bi2S3@C to the sensitizing solution is 0.5-1:50, and the sensitization time is 5-10 min.

5. The method for optimizing bismuth sulfide-based lithium battery negative electrode materials by utilizing multilayer interface construction according to claim 1, characterized in that: The activation solution in step (3) is an AgNO3-ammonia solution, the AgNO3 concentration in the activation solution is 0.1-0.2 g / L, and the pH value is 4-5; the solid-liquid ratio of the precursor Bi2S3@C to the activation solution is g:mL 0.5-1:50, and the activation time is 5-8 min.

6. The method for optimizing bismuth sulfide-based lithium battery negative electrode materials by utilizing multilayer interface construction according to claim 1, characterized in that: Step (3) The chemical plating solution contains metal salt X, reducing agent NaH2PO2·H2O, complexing agent C6H8O7, buffer sodium acetate, accelerator C4H6O4 and surfactant C 12 H 25 NaO3S, the pH value of the chemical plating solution is 4-4.8, the temperature of the chemical plating is 60-90°C, and the time is 4-5h.

7. The method for optimizing bismuth sulfide-based lithium battery negative electrode materials by utilizing multilayer interface construction according to claim 6, characterized in that: The concentration of metal salt X in the chemical plating solution is 20-30 g / L, the concentration of reducing agent NaH2PO2·H2O is 25-35 g / L, the concentration of complexing agent C6H8O7 is 20-30 g / L, the concentration of buffer sodium acetate is 8-10 g / L, the concentration of accelerator C4H6O4 is 7-10 g / L, and the concentration of surfactant C 12 H 25 The concentration of NaO3S is 3-5 mg / L.

8. The method for optimizing bismuth sulfide-based lithium battery negative electrode materials by utilizing multilayer interface construction according to claim 1, characterized in that: In step (4), the mass ratio of polypyrrole to the precursor Bi2S3@C@X is 1 to 5:

100.

9. The method for optimizing bismuth sulfide-based lithium battery negative electrode materials by utilizing multilayer interface construction according to claim 1, characterized in that: The carbonization temperature in step (5) is 400-500° C. and the time is 3-5 hours.

Images