Antimony negative electrode material, preparation method thereof, lithium ion battery and terminal

Abstract

The application relates to the field of secondary batteries, in particular to a kind of antimony negative material and its preparation method, lithium ion battery and terminal, organic ligand containing carboxyl and mercapto, antimony source and polyethylene glycol are mixed to obtain solution A; Sodium borohydride and selenium source are added into ethanol, and then polyethyleneimine is added to obtain solution B; Solution A and solution B are mixed to carry out solvothermal reaction; The solvothermal reaction product is collected, washed and dried, and the lithium ion battery assembled by the antimony-based negative material of the application shows excellent electrochemical performance and can be used in various terminals.

Description

Technical Field

[0001] This invention relates to the field of secondary batteries, specifically to an antimony anode material and its preparation method, a lithium-ion battery, and a terminal. Background Technology

[0002] With the rapid development of portable electronic devices, electric vehicles, and large-scale energy storage systems, the demand for high-energy-density, long-cycle-life lithium-ion batteries is becoming increasingly urgent. Currently, commercially available lithium-ion batteries mainly use graphite as the anode material, but its theoretical specific capacity is low and its rate performance is poor, making it difficult to meet the application requirements of next-generation high-energy-density batteries. Therefore, developing novel high-capacity anode materials has become a current research hotspot.

[0003] Antimony-based materials are considered highly promising next-generation lithium-ion battery anode materials due to their high theoretical specific capacity, suitable operating voltage, and abundant reserves. However, antimony-based materials face severe volume expansion problems during charge and discharge, leading to electrode material pulverization and detachment, which in turn causes rapid capacity decay and poor cycle stability. Furthermore, the low intrinsic electronic conductivity of antimony-based materials limits their rate performance.

[0004] To address these challenges, researchers have developed various strategies, primarily including nanoscale design to shorten lithium-ion diffusion paths and alleviate volumetric stress by reducing particle size; carbon composites to introduce conductive carbon matrices to improve electronic conductivity and buffer volume changes; and the construction of specialized micro / nano structures, such as hollow, porous, and core-shell structures, to provide additional buffering space. Among these, antimony-based materials with three-dimensional hierarchical structures, especially petal-shaped and flower-shaped assemblies, exhibit excellent electrochemical performance due to their high specific surface area, abundant pore structure, and superior structural stability.

[0005] Among the methods for preparing antimony-based materials, the solvothermal method has attracted widespread attention due to its simplicity, high controllability, and ease of large-scale production. Existing solvothermal methods for preparing antimony-based anode materials typically use antimony salts as precursors, directly reacting them with sulfur or selenium sources to obtain antimony sulfide or antimony selenide. However, this method suffers from difficulties in controlling the nucleation and growth processes, easily forming large particles with irregular morphologies, resulting in insufficient exposure of active sites. Furthermore, due to the lack of effective structure-directing agents, it is difficult to construct three-dimensional assemblies with hierarchical structures, and structural collapse easily occurs during cycling.

[0006] Therefore, developing a method for preparing antimony anode materials based on functional organic ligand regulation, precisely controlling the material morphology through coordination, and constructing a stable three-dimensional hierarchical structure by combining structure-directing agents is of great significance for improving the electrochemical performance of antimony-based anode materials. Summary of the Invention

[0007] Purpose of the invention: To address the above-mentioned technical problems, this invention proposes an antimony anode material, its preparation method, a lithium-ion battery, and a terminal.

[0008] The technical solution adopted is as follows: A method for preparing an antimony anode material is as follows: Solution A is obtained by mixing an organic ligand containing carboxyl and thiol groups, an antimony source, and polyethylene glycol; Sodium borohydride and selenium source were added to ethanol, and then polyethyleneimine was added to obtain solution B; Solution A and solution B are mixed and subjected to a solvothermal reaction; Collect the solvothermal reaction products, wash and dry them.

[0009] Furthermore, the structural formula of the organic ligand is as follows: Where L represents an alkylene group.

[0010] Furthermore, L is any one of ethylidene, propyleneide, and butylidene.

[0011] Furthermore, the selenium source is selenium powder.

[0012] Furthermore, the solvothermal reaction is divided into two stages: the temperature of the first stage is 110-130°C, and the temperature of the second stage is 160-170°C.

[0013] Furthermore, the reaction time for the first stage is 3-6 hours, and the reaction time for the second stage is 10-30 hours.

[0014] On the one hand, the present invention also provides an antimony anode material, which is prepared by the above-mentioned method for preparing antimony anode materials.

[0015] Furthermore, the antimony anode material has a petal-like structure.

[0016] On the other hand, the present invention also provides a lithium-ion battery whose structure includes the above-mentioned antimony anode material.

[0017] On the other hand, the present invention also provides a terminal whose structure includes the above-described lithium-ion battery.

[0018] The beneficial effects of this invention are: This invention provides a method for preparing antimony anode materials. By adding a synergistic regulatory system composed of a bifunctional organic ligand containing carboxyl and thiol groups and polyethyleneimine, the microstructure of the generated product is controlled to obtain an antimony-based anode material with a petal-like structure. Specifically, the organic ligand anchors the antimony source through strong coordination between thiol groups and antimony ions, delaying nucleation, and induces anisotropic crystal growth by constructing a two-dimensional coordination network through carboxyl groups, forming a nanosheet structure. Polyethyleneimine, as a long-chain structure directing agent, drives the radial assembly of nanosheets to form a petal-like structure through a micellar template effect. The synergistic effect of the organic ligand and polyethyleneimine achieves multi-level control from atomic-scale coordination regulation to precise assembly of mesoscopic structures. The petal-like structure exposes more active sites for lithium-ion insertion / extraction, promoting electron transfer and electrolyte penetration, and has a certain inhibitory effect on volume expansion during charge-discharge cycles, improving cycle stability and contributing to improved electrochemical performance of the anode material, resulting in excellent performance in lithium-ion batteries.

[0019] When the antimony-based anode material prepared in this invention is applied to lithium-ion batteries, the three-dimensional porous network with a petal-like structure facilitates the full wetting of the electrolyte and the rapid transport of lithium ions, shortens the lithium ion diffusion path, provides isotropic ion transport channels, and reduces electrode polarization. The gaps between the petals effectively buffer the volume expansion of the antimony-based material during charging and discharging, maintaining structural integrity. Lithium-ion batteries assembled from this antimony-based anode material exhibit excellent electrochemical performance and can be used in various terminals. Attached Figure Description

[0020] Figure 1 This is a SEM image of the antimony anode material prepared in Example 1 of the present invention.

[0021] Figure 2 This is a SEM image of the antimony anode material prepared in Comparative Example 1 of this invention.

[0022] Figure 3 This is a SEM image of the antimony anode material prepared in Comparative Example 2 of this invention.

[0023] Figure 4 The image shows the XRD pattern of the antimony anode material prepared in Example 1 of this invention.

[0024] Figure 5 This is a reaction route diagram of the organic ligands prepared in Example 1 of the present invention. Detailed Implementation

[0025] Unless otherwise specified in the examples, the conditions were performed under standard conditions or as recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all commercially available products. Techniques not mentioned in this invention refer to existing technologies. Unless otherwise specified, the following examples and comparative examples are parallel experiments, using the same processing steps and parameters. Example 1:

[0026] A method for preparing antimony anode material: 19.8 g (100 mmol) of 2-mercapto-1,4-phthalic acid was added to 500 mL of anhydrous toluene, and 1 g (5 mmol, 0.05 eq) of p-toluenesulfonic acid was added. The mixture was heated to 40°C and stirred for 10 min. 3.2 g (100 mmol, 1 eq) of anhydrous methanol was slowly added dropwise. After the addition was complete, the mixture was refluxed for 8 h. After the reaction was complete as monitored by TLC, the solvent was removed by vacuum distillation, and the mixture was dissolved in 500 mL of ethyl acetate. The solution was washed with saturated NaHCO3 solution until neutral, washed three times with saturated brine, and dried over anhydrous sodium sulfate. The organic phase was purified by column chromatography (petroleum ether: ethyl acetate = 2:1) after vacuum distillation to obtain the monomethyl ester intermediate.

[0027] 2.12 g (10 mmol) of the above monomethyl ester intermediate and 40 ml of toluene were added to a reaction flask, and 1.79 g (15 mmol, 1.5 eq) of thionyl chloride was added dropwise. After the addition was complete, the reaction was carried out at 60°C for 2 h. The reaction solution was then evaporated under reduced pressure to remove the residual thionyl chloride and solvent to obtain the acyl chloride-methyl ester intermediate. 1.52 g (15 mmol, 1.5 eq) of triethylamine and 50 mL of tetrahydrofuran were added to a reaction flask. The mixture was cooled in an ice-water bath and stirred for 10 min. Then, 0.3 g (5 mmol, diluted with 10 mL of THF and added slowly) of ethylenediamine was added. The mixture was stirred in an ice-water bath for 30 min. The amide-methyl ester intermediate was dissolved in 30 mL of tetrahydrofuran and added slowly. After the addition was complete, the mixture was allowed to rise to room temperature and stirred for 3 h. After the reaction was complete as monitored by TLC, the reaction solution was slowly poured into a 500 g ice-water mixture (containing 3 mL of concentrated hydrochloric acid). The mixture was stirred for 30 min and then extracted three times with 500 mL of ethyl acetate. The organic phases were combined, washed three times with saturated brine, dried over anhydrous sodium sulfate, and purified by column chromatography (ethyl acetate: methanol = 8:2) after vacuum distillation to obtain the amide-methyl ester intermediate.

[0028] The above-mentioned monoamide-methyl ester intermediate was dissolved in 30 mL of a tetrahydrofuran / water (v / v = 1:1) mixed solvent, cooled in an ice-water bath, and 0.50 g (12 mmol, 1.5 eq) of lithium hydroxide monohydrate was added. The mixture was naturally heated to room temperature and stirred for 2 h. After complete ester hydrolysis was monitored by TLC, the solution was acidified to pH = 2-3 with 1 M hydrochloric acid, extracted with ethyl acetate (3 × 50 mL), and the organic phases were combined. The organic phases were washed three times with saturated brine, dried over anhydrous sodium sulfate, and purified by column chromatography (ethyl acetate:methanol = 8:2) after vacuum distillation to obtain the organic ligand. The reaction route diagram is shown below. Figure 5 ESI-MS (m / z)(M + ): Theoretical value 420.45, measured value 420.59, HPLC purity 99.3%. (DMSO, 400MHz) δ: 12.85 (br s, 2H), 8.62 (t, J = 5.6 Hz, 2H), 7.95 (d, J = 8.0 Hz, 2H), 7.88 (s, 2H), 7.52 (d, J = 8.0 Hz, 2H), 3.52-3.56 (m, 4H).

[0029] 0.1 g of organic ligand and 2 mmol of SbCl3 were placed in a 100 ml reaction flask, and 60 ml of polyethylene glycol-400 was added. The mixture was stirred thoroughly to obtain solution A. 3 mmol of sodium borohydride and 3 mmol of selenium powder were added to 60 ml of ethanol, and the mixture was shaken for 10 min. Then, 0.4 g of polyethyleneimine (molecular weight 1800) was added and stirred until homogeneous to obtain solution B. Solutions A and B were mixed and stirred thoroughly. The mixture was then transferred to a polytetrafluoroethylene-lined reactor and sealed for a solvothermal reaction. The solvothermal reaction consisted of two stages: the first stage was at 120°C for 4 h, and the second stage was at 165°C for 24 h. After the reaction, the mixture was allowed to return to room temperature. The resulting black precipitate was washed three times each with 1 mol / L sodium hydroxide solution, anhydrous ethanol, and distilled water. Finally, the product was dried in a 60°C oven to obtain the antimony anode material with a petal-like structure. Its SEM image is shown below. Figure 1 Its XRD pattern is shown in Figure 4 As can be seen from the XRD pattern, the antimony anode material prepared at this time is pure phase Sb2Se3, and the characteristic peaks correspond completely to the standard PDF#89-0821. Example 2:

[0030] A method for preparing antimony anode material: The organic ligand was prepared in the same way as in Example 1. 0.1 g of organic ligand and 2 mmol of SbCl3 were placed in a 100 ml reaction flask, and 60 ml of polyethylene glycol-400 was added. The mixture was stirred thoroughly to obtain solution A. 3 mmol of sodium borohydride and 3 mmol of selenium powder were added to 60 ml of ethanol, and the mixture was shaken for 10 min. Then, 0.4 g of polyethyleneimine (molecular weight 1800) was added and stirred until homogeneous to obtain solution B. Solution A and solution B were mixed and stirred until homogeneous. The mixture was then transferred to a reaction vessel with a polytetrafluoroethylene liner and sealed for a solvothermal reaction. The solvothermal reaction was divided into two stages. The temperature of the first stage was 130°C and the reaction time was 6 h. The temperature of the second stage was 170°C and the reaction time was 30 h. After the reaction was completed, the mixture was allowed to return to room temperature. The resulting black precipitate was washed three times each with 1 mol / L sodium hydroxide solution, anhydrous ethanol, and distilled water. Finally, the product was dried in a 60°C oven to obtain the antimony anode material with a petal-like structure. Example 3:

[0031] A method for preparing antimony anode material: The organic ligand was prepared in the same way as in Example 1. 0.1 g of organic ligand and 2 mmol of SbCl3 were placed in a 100 ml reaction flask, and 60 ml of polyethylene glycol-400 was added. The mixture was stirred thoroughly to obtain solution A. 3 mmol of sodium borohydride and 3 mmol of selenium powder were added to 60 ml of ethanol, and the mixture was shaken for 10 min. Then, 0.4 g of polyethyleneimine (molecular weight 1800) was added and stirred until homogeneous to obtain solution B. Solution A and solution B were mixed and stirred until homogeneous. The mixture was then transferred to a reaction vessel with a polytetrafluoroethylene liner and sealed for a solvothermal reaction. The solvothermal reaction was divided into two stages. The temperature of the first stage was 110°C and the reaction time was 3 h. The temperature of the second stage was 160°C and the reaction time was 20 h. After the reaction was completed, the mixture was allowed to return to room temperature. The resulting black precipitate was washed three times each with 1 mol / L sodium hydroxide solution, anhydrous ethanol, and distilled water. Finally, the product was dried in a 60°C oven to obtain the antimony anode material with a petal-like structure. Example 4:

[0032] A method for preparing antimony anode material: The organic ligand was prepared in the same way as in Example 1. 0.1 g of organic ligand and 2 mmol of SbCl3 were placed in a 100 ml reaction flask, and 60 ml of polyethylene glycol-400 was added. The mixture was stirred thoroughly to obtain solution A. 3 mmol of sodium borohydride and 3 mmol of selenium powder were added to 60 ml of ethanol, and the mixture was shaken for 10 min. Then, 0.4 g of polyethyleneimine (molecular weight 1800) was added and stirred until homogeneous to obtain solution B. Solution A and solution B were mixed and stirred until homogeneous. The mixture was then transferred to a reaction vessel with a polytetrafluoroethylene liner and sealed for a solvothermal reaction. The solvothermal reaction was divided into two stages. The temperature of the first stage was 130°C and the reaction time was 3 h. The temperature of the second stage was 170°C and the reaction time was 20 h. After the reaction was completed, the mixture was allowed to return to room temperature. The resulting black precipitate was washed three times each with 1 mol / L sodium hydroxide solution, anhydrous ethanol, and distilled water. Finally, the product was dried in a 60°C oven to obtain the antimony anode material with a petal-like structure. Example 5:

[0033] A method for preparing antimony anode material: The organic ligand was prepared in the same way as in Example 1. 0.1 g of organic ligand and 2 mmol of SbCl3 were placed in a 100 ml reaction flask, and 60 ml of polyethylene glycol-400 was added. The mixture was stirred thoroughly to obtain solution A. 3 mmol of sodium borohydride and 3 mmol of selenium powder were added to 60 ml of ethanol, and the mixture was shaken for 10 min. Then, 0.4 g of polyethyleneimine (molecular weight 1800) was added and stirred until homogeneous to obtain solution B. Solution A and solution B were mixed and stirred until homogeneous. The mixture was then transferred to a reaction vessel with a polytetrafluoroethylene liner and sealed for a solvothermal reaction. The solvothermal reaction was divided into two stages. The temperature of the first stage was 110°C and the reaction time was 6 h. The temperature of the second stage was 160°C and the reaction time was 30 h. After the reaction was completed, the mixture was allowed to return to room temperature. The resulting black precipitate was washed three times each with 1 mol / L sodium hydroxide solution, anhydrous ethanol, and distilled water. Finally, the product was dried in a 60°C oven to obtain the antimony anode material with a petal-like structure.

[0034] Comparative Example 1: The method is basically the same as in Example 1, except that no organic ligand is added. The specific method is as follows: 2 mmol SbCl3 was placed in a 100 ml reaction flask, and 60 ml of polyethylene glycol-400 was added. The mixture was stirred thoroughly until completely dissolved to obtain solution A. 3 mmol sodium borohydride and 3 mmol selenium powder were added to 60 ml ethanol, and the mixture was shaken for 10 min. Then, 0.4 g of polyethyleneimine (molecular weight 1800) was added and stirred until homogeneous to obtain solution B. Solutions A and B were mixed and stirred thoroughly. The mixture was then transferred to a polytetrafluoroethylene-lined reactor and sealed for a solvothermal reaction. The solvothermal reaction consisted of two stages: the first stage was at 120°C for 4 h, and the second stage was at 165°C for 24 h. After the reaction, the mixture was allowed to return to room temperature. The resulting black precipitate was washed three times each with 1 mol / L sodium hydroxide solution, anhydrous ethanol, and distilled water. Finally, the product was dried in a 60°C oven to obtain the antimony anode material. Its SEM image is shown below. Figure 2 It consists of irregular large particles / mass aggregates.

[0035] Comparative Example 2: The method is basically the same as in Example 1, except that polyethyleneimine (molecular weight 1800) is not added. The specific method is as follows: The organic ligand was prepared using the same method as in Example 1. 0.1 g of the organic ligand and 2 mmol of SbCl3 were placed in a 100 ml reaction flask, and 60 ml of polyethylene glycol-400 was added. The mixture was stirred thoroughly to obtain solution A. 3 mmol of sodium borohydride and 3 mmol of selenium powder were added to 60 ml of ethanol, and the mixture was shaken for 10 min to obtain solution B. Solutions A and B were mixed and stirred until homogeneous. The mixture was then transferred to a polytetrafluoroethylene-lined reactor and sealed for a solvothermal reaction. The solvothermal reaction consisted of two stages: the first stage was at 120°C for 4 h, and the second stage was at 165°C for 24 h. After the reaction, the mixture was allowed to return to room temperature. The resulting black precipitate was washed three times each with 1 mol / L sodium hydroxide solution, anhydrous ethanol, and distilled water. Finally, the product was dried in a 60°C oven to obtain the antimony anode material. Its SEM image is shown below. Figure 3 This is due to the disordered stacking of nanoparticles / sheets.

[0036] Performance testing: The antimony anode materials prepared in Examples 1-5 and Comparative Examples 1-2, along with commercially available antimony sulfide (Zhongke Oude), conductive agent acetylene black, and binder PVDF, were mixed at a mass ratio of 8:1:1. The mixture was then thoroughly ground in an agate mortar. An appropriate amount of N-methylpyrrolidone was added, and the mixture was stirred into a slurry. This slurry was then coated onto a clean copper foil to form a working electrode sheet. The electrode sheet was placed in a vacuum drying oven and dried at 90°C for 12 hours. The dried electrode sheet was then cut into small round pieces with a diameter of 14 mm using a punch, weighed, and vacuum dried at 120°C for 24 hours. Lithium foil was used as the counter electrode, and a 1 mol / L LiPF6 solution and a 1:1 volume ratio EC and DEC mixed solution were used as the electrolyte. The battery was assembled in an argon-atmospheric glove box, pressed and sealed, and allowed to stand for 8 hours before electrochemical performance testing. The electrochemical performance was tested on a Blue Battery testing system, using a CH1600E electrochemical workstation for cyclic voltammetry (CV) testing. The voltage range was 0.05–3.00 V, and the current density was 1.0 A / g. The test results are shown in Table 1 below. The test results are shown in Table 1 below: Table 1: As shown in Table 1 above, the antimony anode material prepared by this invention has excellent electrochemical performance.

[0037] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing an antimony anode material, characterized in that, Specifically as follows: Solution A is obtained by mixing an organic ligand containing carboxyl and thiol groups, an antimony source, and polyethylene glycol; Sodium borohydride and selenium source were added to ethanol, and then polyethyleneimine was added to obtain solution B; Solution A and solution B are mixed and subjected to a solvothermal reaction; Collect the solvothermal reaction products, wash and dry them.

2. The method for preparing the antimony anode material as described in claim 1, characterized in that, The structural formula of the organic ligand is as follows: ； Where L represents an alkylene group.

3. The method for preparing the antimony anode material as described in claim 2, characterized in that, L is any one of ethylidene, propyleneide, and butylidene.

4. The method for preparing the antimony anode material as described in claim 1, characterized in that, The selenium source is selenium powder.

5. The method for preparing the antimony anode material as described in claim 1, characterized in that, The solvothermal reaction is divided into two stages: the temperature of the first stage is 110-130°C, and the temperature of the second stage is 160-170°C.

6. The method for preparing the antimony anode material as described in claim 6, characterized in that, The reaction time for the first stage is 3-6 hours, and the reaction time for the second stage is 10-30 hours.

7. An antimony anode material, characterized in that, It is prepared by the method for preparing antimony anode material according to any one of claims 1-6.

8. The antimony anode material as described in claim 7, characterized in that, The antimony anode material has a petal-like structure.

9. A lithium-ion battery, characterized in that, Including the antimony anode material as described in claim 7.

10. A terminal, characterized in that, Including the lithium-ion battery as described in claim 9.

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