High-performance antimony-based electrode material and preparation method thereof

Abstract

The application relates to the field of secondary batteries, in particular to a high-performance antimony-based electrode material and a preparation method thereof, which comprises the following steps: preparing an antimony alloy core; preparing an intermediate layer by chemical vapor deposition with organic phosphorus as a precursor; and finally preparing a nitrogen-sulfur co-doped porous carbon shell on the surface of the intermediate layer; in the application, the antimony alloy core provides high-capacity sodium storage active sites, the carbon-doped composite metal phosphide layer, i.e. the intermediate layer, bears stress buffering and electron conduction functions, and the nitrogen-sulfur co-doped porous carbon shell provides mechanical confinement, surface stability and an ion rapid transmission channel; the three form a close chemical bonding interface, the interface peeling problem of traditional physical coating is avoided, and the cycle stability of the electrode material is significantly improved.

Description

Technical Field

[0001] This invention relates to the field of secondary batteries, specifically to a high-performance antimony-based electrode material and its preparation method. Background Technology

[0002] Electrochemical energy storage technology has become a key enabling technology supporting the large-scale application of renewable energy, the popularization of electric vehicles, and the construction of smart grids. Lithium-ion batteries, with their advantages of high energy density, long cycle life, and no memory effect, have achieved widespread commercial application in portable electronic devices, electric vehicles, and large-scale energy storage. However, lithium resources are scarce in the Earth's crust and their geographical distribution is extremely uneven. The significant fluctuations in lithium resource prices in recent years have posed a severe challenge to the sustainable development of the lithium-ion battery industry chain.

[0003] Sodium-ion batteries are considered the most promising alternative and supplementary technology to lithium-ion batteries in the field of large-scale energy storage due to the high abundance and wide distribution of sodium resources in the Earth's crust and their low cost. However, the larger radius of sodium ions compared to lithium ions results in more sluggish diffusion kinetics of sodium ions in electrode materials, and the volume changes experienced by the electrode materials during sodium insertion / extraction are also more drastic. This places higher technical demands on the structural stability and cycle life of the electrode materials.

[0004] Whether it's a lithium-ion or sodium-ion battery, the anode material is one of the key components determining the overall performance of the battery. Currently, commercially available lithium-ion battery anode materials are mainly graphite-based carbon materials, with a theoretical specific capacity of only 372 mAh / g, which is insufficient to meet the growing demands for long driving ranges in electric vehicles and high energy density in energy storage systems. In the field of sodium-ion batteries, due to the large radius of sodium ions, it is difficult for them to effectively intercalate between graphite layers, making hard carbon the mainstream choice, but its specific capacity is also limited. Therefore, developing novel anode materials that combine high specific capacity and excellent cycle stability has become a core research topic and an urgent industrial need in the field of electrochemical energy storage. Summary of the Invention

[0005] Purpose of the invention: To address the above-mentioned technical problems, this invention proposes a high-performance antimony-based electrode material and its preparation method.

[0006] The technical solution adopted is as follows: A method for preparing a high-performance antimony-based electrode material includes: Preparation of antimony alloy core; An intermediate layer was prepared by chemical vapor deposition using organophosphorus compounds as precursors. Finally, a nitrogen-sulfur co-doped porous carbon shell was prepared on the surface of the intermediate layer.

[0007] Furthermore, the antimony alloy core is an Sb-Bi-M ternary alloy particle, where M is a transition metal element.

[0008] Furthermore, the atomic ratio of Sb, Bi, and M in the Sb-Bi-M ternary alloy particles is 1:0.1-0.2:0.01-0.05.

[0009] Compared to antimony-based materials, the introduction of bismuth leverages its crystal structure similarity to antimony (belonging to the same group VA) to form a solid solution alloy phase. This phase generates a synergistic buffering effect during sodium addition / removal, significantly reducing localized stress concentration caused by lattice parameter differences. Simultaneously, bismuth possesses high electronic conductivity and a suitable sodium addition potential, optimizing the overall electrochemical reaction kinetics of the alloy core. The doping of transition metal elements introduces atomic-scale distortions and defects into the lattice. These defect sites not only provide additional sodium-storing active sites but also act as buffer regions for volume expansion, effectively suppressing the pulverization of alloy particles during cycling. This reduces the volume expansion rate to a more controllable range, providing a stable structural basis for subsequent intermediate layers and carbon shell coatings.

[0010] Controlling the bismuth content within a specific range can prevent excessive loss of specific capacity due to bismuth introduction, while ensuring sufficient stress buffering. The content of transition metal elements is relatively low, which can both refine and strengthen the grains without significantly reducing the specific capacity due to the formation of too many electrochemically inert phases.

[0011] Furthermore, M is at least one of Mn, Fe, Co, Ni, Cu, and Zn.

[0012] These transition metal elements possess a moderate alloying enthalpy with antimony, enabling them to co-deposit with antimony under liquid-phase reduction or solvothermal synthesis conditions to form uniform alloy nanoparticles. Among them, elements such as zinc and manganese can also undergo interfacial reactions with the phosphorus-containing intermediate layer during carbonization or phosphating, forming interfacial phosphides, further strengthening the bonding between the core and the intermediate layer. From an electrochemical perspective, copper, iron, cobalt, and nickel possess certain catalytic activities, potentially promoting the graphitization of the carbon shell or improving the properties of the surface SEI film.

[0013] Furthermore, the particle size of the antimony alloy core is ≤100nm.

[0014] Nanoscale alloy cores can significantly shorten the solid-state diffusion distance of sodium ions and reduce the absolute volume change of individual particles, thereby reducing the risk of stress cracking caused by volume anisotropy within the particles. Simultaneously, uniform nanoscale particles facilitate homogeneous composite formation with the intermediate layer and carbon shell, maximizing the effect of the multi-level structure.

[0015] Furthermore, the organophosphorus compound is at least one of triphenylphosphine, triethyl phosphate, and tri-n-octylphosphine.

[0016] A key innovation of this invention is the preparation of an intermediate layer via chemical vapor deposition using organophosphorus precursors. Under appropriate temperature and carrier gas conditions, the organophosphorus precursors can uniformly pyrolyze and form a dense, controllable-thickness intermediate layer (composition of the intermediate layer includes Sb-P, Bi-P, MP, and trace amounts of amorphous carbon) on the surface of the alloy core. Compared with the use of highly toxic and reactive gases such as phosphine, organophosphorus precursors have significant advantages such as low toxicity, safe operation, moderate pyrolysis rate, and good deposition uniformity. Pyrolysis generates phenyl radicals and phosphorus radicals. Phosphorus radicals can deposit on the alloy surface to form phosphides, while carbon-containing organic fragments can undergo carbon doping, enhancing affinity with the subsequent carbon shell and improving electrochemical performance.

[0017] Furthermore, the temperature during chemical vapor deposition is 350-450℃.

[0018] If the temperature is too low, the organophosphorus precursor will not be completely pyrolyzed, resulting in a slow deposition rate and poor density of the intermediate layer; if the temperature is too high, the alloy core particles may sinter and grow, and the decomposition of the organophosphorus precursor will be too violent, making it difficult to form a uniform coating.

[0019] Furthermore, the nitrogen-sulfur co-doped porous carbon shell is made of a carbon source precursor, a nitrogen-sulfur dual doping source, and a pore-forming agent in a mass ratio of 1:0.2-0.3:0.25-0.35.

[0020] The carbon source precursor provides the main carbon framework; the nitrogen-sulfur dual-doping source introduces nitrogen and sulfur atoms in situ into the carbon lattice during carbonization, forming structural defects and electrochemical active centers; the pore-forming agent undergoes thermal decomposition during carbonization, generating a large number of micropores and mesopores, thereby constructing a three-dimensional interconnected porous carbon shell. Within this ratio range, it is possible to ensure that the carbon shell has sufficient mechanical strength to restrain the volume expansion of the core, while also introducing sufficient nitrogen and sulfur doping atoms and suitable porosity to achieve rapid ion transport and efficient electrolyte wetting.

[0021] Furthermore, the nitrogen-sulfur dual-doping source is at least one of thiourea, cysteine, and methionine. The molecular structure of the above structure simultaneously contains nitrogen and sulfur elements, enabling uniform molecular-level doping of nitrogen and sulfur during the carbonization process.

[0022] Furthermore, the pore-forming agent is a thermally decomposable polymer such as polyvinylpyrrolidone, polymethyl methacrylate, or polyethylene glycol. These polymers decompose and volatilize during carbonization, leaving behind numerous pores without remaining in the carbon skeleton. Polyvinylpyrrolidone (PVP) is particularly preferred, as it acts not only as a pore-forming agent but also as a dispersant and surface stabilizer during the liquid-phase mixing stage.

[0023] Furthermore, the carbon source precursor is a soluble or dispersible carbon-containing precursor such as glucose, sucrose, citric acid, or phenolic resin. Glucose is preferred due to its high carbonization yield, low cost, and environmental friendliness. The carbonization temperature is typically 500-700℃, the time is 2-4 hours, and the process is carried out under an inert atmosphere.

[0024] The present invention also provides a high-performance antimony-based electrode material, which is prepared by the above-described method for preparing high-performance antimony-based electrode materials.

[0025] The antimony alloy core provides high reversible sodium / lithium storage capacity. The phosphorus-containing intermediate layer acts as an interface transition and strong chemical bond. On the one hand, it forms interfacial phosphide chemical bonds (such as Sb-P, Bi-P, MP, etc.) to firmly connect the alloy core and the carbon shell, preventing "shell detachment" during cycling. On the other hand, the phosphorus intermediate layer itself has certain electrochemical activity and conductivity, which can partially participate in sodium / lithium storage and promote interfacial charge transfer, providing high-mobility electron channels. The outermost nitrogen-sulfur co-doped porous carbon shell acts as an elastic buffer armor, effectively constraining the volume expansion of the alloy core during charging and discharging. At the same time, the three-dimensional porous structure and heteroatom doping provide abundant ion / electron transport highways and additional active sodium / lithium storage sites, improving the rate performance and reversible capacity of the electrode material.

[0026] The technical solution provided by this invention has the following significant beneficial effects: Compared to antimony-based materials, the introduction of bismuth leverages its crystal structure similarity to antimony (belonging to the same group VA) to form a solid solution alloy phase. This phase generates a synergistic buffering effect during sodium addition / removal, significantly reducing localized stress concentration caused by lattice parameter differences. Simultaneously, bismuth possesses high electronic conductivity and a suitable sodium addition potential, optimizing the overall electrochemical reaction kinetics of the alloy core. The doping of transition metal elements introduces atomic-scale distortions and defects into the lattice. These defect sites not only provide additional sodium-storing active sites but also act as buffer regions for volume expansion, effectively suppressing the pulverization of alloy particles during cycling. This reduces the volume expansion rate to a more controllable range, providing a stable structural basis for subsequent intermediate layers and carbon shell coatings.

[0027] A carbon-doped composite metal phosphide buffer layer (Sb-P, Bi-P, MP) was constructed in situ on the surface of an antimony alloy core using chemical vapor deposition. Aromatic ring carbon doping was also incorporated, thus achieving synergy between phosphating and carbon doping in the same process step. The composite metal phosphide provides a high-mobility electron channel, while the amorphous carbon enhances the affinity with the subsequent carbon shell and improves electrochemical performance. The two work together to achieve a triple function of conductivity, buffering, and interface compatibility, effectively alleviating the volume expansion stress of the alloy core during charging and discharging and reducing the interfacial charge transport impedance.

[0028] The interconnected pore structure of the nitrogen-sulfur co-doped porous carbon shell significantly shortens the ion diffusion distance and reduces ion transport resistance; nitrogen-sulfur co-doping improves the electronic conductivity and surface wettability of the carbon shell, promoting interfacial charge transfer. These multiple measures enable the electrode material to maintain a high specific capacity even at high current densities.

[0029] In this invention, the antimony alloy core provides high-capacity sodium storage active sites, the carbon-doped composite metal phosphide layer (intermediate layer) undertakes stress buffering and electronic conduction functions, and the nitrogen-sulfur co-doped porous carbon shell provides mechanical confinement, surface stability, and rapid ion transport channels. The three form a tight chemical bond interface, avoiding the interface peeling problem of traditional physical coatings, and significantly improving the cycle stability of the electrode material. Detailed Implementation

[0030] 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.

[0031] Example 1: A method for preparing a high-performance antimony-based electrode material: S1: Weigh 10 mmol of antimony trichloride, 1.5 mmol of bismuth nitrate, and 0.25 mmol of zinc acetate, dissolve them in 100 mL of triethylene glycol to obtain a transparent solution. Add 2.5 g of polyvinylpyrrolidone (PVP K30) and 2 mL of oleylamine as a surfactant and coordination stabilizer to the solution, and continue stirring for 60 min to completely dissolve and form a homogeneous solution. Under nitrogen protection, heat the solution to 200-210°C at a heating rate of 3°C / min and maintain the temperature for 120 min. During the reaction, the solution color changes from pale yellow to dark gray and then to black. After the reaction is completed, allow it to cool naturally to 80°C, add 200 mL of anhydrous ethanol to dilute and terminate the reaction, collect the solid by centrifugation, wash it three times each with anhydrous ethanol and acetone, and finally vacuum dry it for 12 h to obtain Sb-Bi-Zn ternary alloy nanoparticles with a particle size of 20-40 nm. S2: Sb-Bi-Zn ternary alloy nanoparticles were uniformly spread in a quartz boat. The quartz boat was placed in the center of the isothermal zone of a CVD tube furnace. After sealing the CVD system, high-purity argon gas was introduced and the system was purged at a flow rate of 100 sccm for 30 min. Subsequently, the tube furnace was heated to 400°C at a heating rate of 5°C / min. A heating flask containing 0.8 g of triphenylphosphine was heated to 180°C. After the temperature of the tube furnace stabilized, the supply valve was opened, and high-purity argon gas (flow rate 50 sccm) was used as the carrier gas to introduce triphenylphosphine into the reaction zone of the tube furnace. The deposition temperature was maintained at 400°C and the working pressure at approximately 30 Pa for 2 h. After the reaction was completed, the supply valve was closed, but high-purity argon gas was continued to flow, allowing the system to cool naturally to room temperature. The product was then removed, yielding core-shell particles. S3: Disperse 1g of the above core-shell particles in a mixed solvent of 80mL anhydrous ethanol and 20mL deionized water, and ultrasonically disperse for 30min. Under stirring, add 1g glucose, 0.25g thiourea, and 0.3g polyvinylpyrrolidone sequentially. Stir at 70-78°C for 2h to ensure uniform mixing and adsorption onto the surface of the core-shell particles, forming a slurry. Concentrate the slurry under reduced pressure to remove anhydrous ethanol, obtaining the precursor-coated core-shell particles. After vacuum drying, transfer to a tube furnace and heat to 600°C at a rate of 3°C / min under a high-purity argon atmosphere, holding at this temperature for 3h, then allow to cool naturally to room temperature. Remove the product, wash three times each with deionized water and anhydrous ethanol, and vacuum dry to obtain the final product.

[0032] Example 2: This example is basically the same as Example 1, except that ferrous chloride is used instead of zinc acetate in the same molar amount.

[0033] Example 3: This example is basically the same as Example 1, except that the same molar amount of manganese acetate is used instead of zinc acetate.

[0034] Example 4: This example is basically the same as Example 1, except that the same molar amount of copper acetate is used instead of zinc acetate.

[0035] Example 5: This example is basically the same as Example 1, except that the same molar amount of cobalt acetate is used instead of zinc acetate.

[0036] Example 6: This example is basically the same as Example 1, except that the same molar amount of nickel nitrate is used instead of zinc acetate.

[0037] Comparative Example 1: This comparative example is basically the same as Example 1, except that: nano-elemental antimony particles with a particle size of 20-40nm are used instead of Sb-Bi-Zn ternary alloy nanoparticles.

[0038] Comparative Example 2: This comparative example is basically the same as Example 1, except that it does not go through step S2; A method for preparing a high-performance antimony-based electrode material: 10 mmol of antimony trichloride, 1.5 mmol of bismuth nitrate, and 0.25 mmol of zinc acetate were weighed and dissolved in 100 mL of triethylene glycol to obtain a clear solution. 2.5 g of polyvinylpyrrolidone (PVP K30) and 2 mL of oleylamine were added to the solution as a surfactant and coordination stabilizer, and the mixture was stirred for 60 min to ensure complete dissolution and the formation of a homogeneous solution. Under nitrogen protection, the solution was heated to 200-210°C at a heating rate of 3°C / min and held at this temperature for 120 min. During the reaction, the solution color changed from pale yellow to dark gray and then to black. After the reaction was completed, the solution was naturally cooled to 80°C, and 200 mL of anhydrous ethanol was added to dilute and terminate the reaction. The solid was collected by centrifugation, washed three times each with anhydrous ethanol and acetone, and finally dried under vacuum for 12 h to obtain Sb-Bi-Zn ternary alloy nanoparticles with a particle size of 20-40 nm.

[0039] 1 g of the above Sb-Bi-Zn ternary alloy nanoparticles were dispersed in a mixed solvent of 80 mL anhydrous ethanol and 20 mL deionized water, and ultrasonically dispersed for 30 min. Under stirring, 1 g of glucose, 0.25 g of thiourea, and 0.3 g of polyvinylpyrrolidone were added sequentially. The mixture was stirred at 70-78°C for 2 h to ensure uniform mixing and adsorption onto the surface of the core-shell particles, forming a slurry. The slurry was concentrated under reduced pressure to remove anhydrous ethanol, yielding the precursor-coated core-shell particles. After vacuum drying, the particles were transferred to a tube furnace and heated from room temperature to 600°C at a rate of 3°C / min under a high-purity argon atmosphere. The temperature was held for 3 h and then naturally cooled to room temperature. The product was then washed three times each with deionized water and anhydrous ethanol, and vacuum dried to obtain the final product.

[0040] Comparative Example 3: This comparative example is basically the same as Example 1, except that phosphine is used instead of triphenylphosphine. A method for preparing a high-performance antimony-based electrode material: S1: Weigh 10 mmol of antimony trichloride, 1.5 mmol of bismuth nitrate, and 0.25 mmol of zinc acetate, and dissolve them in 100 mL of triethylene glycol to obtain a transparent solution. Add 2.5 g of polyvinylpyrrolidone (PVP K30) and 2 mL of oleylamine as a surfactant and coordination stabilizer to the solution, and continue stirring for 60 min to completely dissolve and form a homogeneous solution. Under nitrogen protection, heat the solution to 200-210°C at a heating rate of 3°C / min and maintain the temperature for 120 min. During the reaction, the solution color changes from pale yellow to dark gray and then to black. After the reaction is completed, allow it to cool naturally to 80°C, add 200 mL of anhydrous ethanol to dilute and terminate the reaction, collect the solid by centrifugation, wash it three times each with anhydrous ethanol and acetone, and finally vacuum dry it for 12 h to obtain Sb-Bi-Zn ternary alloy nanoparticles with a particle size of 20-40 nm.

[0041] S2: Sb-Bi-Zn ternary alloy nanoparticles were uniformly spread in a quartz boat. The quartz boat was placed in the center of the isothermal zone of a CVD tube furnace. After sealing the CVD system, high-purity argon gas was introduced and the system was purged at a flow rate of 100 sccm for 30 min. Subsequently, the tube furnace was heated to 400°C at a heating rate of 5°C / min. A mixture of phosphine and argon gas (phosphine volume fraction of 5%) was used as the gaseous phosphorus source. After the tube furnace temperature stabilized, the supply valve was opened, and the gaseous phosphorus source was introduced into the reaction zone at a flow rate of 50 sccm through a mass flow controller. The deposition temperature was maintained at 400°C and the working pressure at approximately 30 Pa for 2 h. After the reaction was completed, the supply valve was closed, but high-purity argon gas continued to flow, allowing the system to cool naturally to room temperature. The product was then removed, yielding core-shell particles.

[0042] S3: Disperse 1g of the above core-shell particles in a mixed solvent of 80mL anhydrous ethanol and 20mL deionized water, and ultrasonically disperse for 30min. Under stirring, add 1g glucose, 0.25g thiourea, and 0.3g polyvinylpyrrolidone sequentially. Stir at 70-78°C for 2h to ensure uniform mixing and adsorption onto the surface of the core-shell particles, forming a slurry. Concentrate the slurry under reduced pressure to remove anhydrous ethanol, obtaining the precursor-coated core-shell particles. After vacuum drying, transfer to a tube furnace and heat to 600°C at a rate of 3°C / min under a high-purity argon atmosphere, holding at this temperature for 3h, then allow to cool naturally to room temperature. Remove the product, wash three times each with deionized water and anhydrous ethanol, and vacuum dry to obtain the final product.

[0043] Comparative Example 4: This comparative example is basically the same as Example 1, except that thiourea is not added in S3.

[0044] Comparative Example 5: This comparative example is basically the same as Example 1, except that polyvinylpyrrolidone is not added in S3.

[0045] Performance testing: The electrode materials prepared in Examples 1-6 and Comparative Examples 1-5 were used as samples for performance testing.

[0046] The sample, conductive carbon black (Super P), and polyvinylidene fluoride were mixed at a mass ratio of 8:1:1. An appropriate amount of N-methylpyrrolidone (NMP) was added and ground to form a uniform slurry. This slurry was coated onto copper foil and vacuum-dried at 110°C for 12 hours. The slurry was then cut into circular electrode sheets with a diameter of 12 mm. Using a sodium metal sheet as the counter electrode, 1M NaPF6 / EC+DMC (volume ratio 1:1) as the electrolyte, and Celgard 2400 as the separator, a CR2032 coin cell was assembled in an argon glove box. After standing for 24 hours, a constant current charge-discharge test was performed in the range of 0.01-3.00 V, first cycling 10 times at 0.1 A / g, followed by 1000 cycles at 1 A / g.

[0047] The test results are shown in Table 1 below; Table 1:

[0048] As shown in Table 1 above, the antimony-based electrode material of the present invention has excellent electrochemical performance.

[0049] A comparison of Example 1 and Comparative Example 1 shows that Comparative Example 1 uses nano-sized antimony particles, which have a theoretically higher specific capacity, making its higher initial discharge capacity than Example 1 reasonable. However, pure antimony undergoes significant volume expansion during sodium intercalation, lacking the synergistic buffering effect of bismuth-formed solid solution and the defect buffering region introduced by zinc in the crystal lattice, resulting in severe pulverization after 1000 cycles. Consequently, the capacity retention rate drops sharply.

[0050] A comparison of Example 1 and Comparative Example 2 shows that Comparative Example 2 omits the intermediate layer deposition step, allowing the alloy core to directly contact the carbon shell. Under repeated volume expansion and contraction, rapid "shell removal" occurs, exposing the core and causing it to pulverize. This clearly demonstrates that the intermediate layer design is essential for long lifespan.

[0051] A comparison of Example 1 and Comparative Example 3 shows that Comparative Example 3, using phosphine gas for phosphating, also formed a composite metal phosphide interlayer, but lacked the carbon doping resulting from organophosphorus pyrolysis. Carbon doping enhances the affinity with the subsequent carbon shell, forming a denser and more stable interface transition. Comparative Example 3, lacking this carbon doping, has poorer interfacial compatibility with the carbon shell, making it prone to microcracks and interface separation during long-term cycling, thus resulting in a significantly lower retention rate than Example 1. The slightly lower capacity may also be due to the slightly lower electronic conductivity of the undoped interlayer.

[0052] A comparison of Example 1 and Comparative Example 4 shows that Comparative Example 4 did not add thiourea in step S3, and therefore lacked nitrogen-sulfur co-doping in the outermost carbon shell. After nitrogen and sulfur atoms enter the carbon lattice, they form structural defects and electrochemical active centers, increasing sodium storage sites and improving electronic conductivity and surface wettability. The undoped carbon shell contributes little to sodium storage capacity and has poor conductivity and electrolyte wettability, leading to an initial capacity decrease. During long-term cycling, the doped carbon shell better buffers volume changes and maintains stable ion / electron channels, while the undoped carbon shell is more prone to performance degradation due to structural fatigue, resulting in a significant decline in retention. This confirms the dual contribution of nitrogen-sulfur co-doping to both capacity and cycle life.

[0053] A comparison of Example 1 and Comparative Example 5 shows that Comparative Example 5 did not include the pore-forming agent PVP, resulting in a carbon shell lacking a porous structure and exhibiting high density. In contrast, the porous structure of the carbon shell provides rapid ion transport channels and an electrolyte reservoir, and can elastically buffer core expansion. The dense, non-porous carbon shell leads to a long sodium ion diffusion path, poor rate capability, and increased brittleness under volume expansion.

[0054] 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 a high-performance antimony-based electrode material, characterized in that, include: Preparation of antimony alloy core; An intermediate layer was prepared by chemical vapor deposition using organophosphorus compounds as precursors. Finally, a nitrogen-sulfur co-doped porous carbon shell was prepared on the surface of the intermediate layer.

2. The method for preparing the high-performance antimony-based electrode material as described in claim 1, characterized in that, The antimony alloy core consists of Sb-Bi-M ternary alloy particles, where M is a transition metal element.

3. The method for preparing the high-performance antimony-based electrode material as described in claim 2, characterized in that, The atomic ratio of Sb, Bi, and M in the Sb-Bi-M ternary alloy particles is 1:0.1-0.2:0.01-0.

05.

4. The method for preparing the high-performance antimony-based electrode material as described in claim 2, characterized in that, M is at least one of Mn, Fe, Co, Ni, Cu, and Zn.

5. The method for preparing the high-performance antimony-based electrode material as described in claim 1, characterized in that, The particle size of the antimony alloy core is ≤100nm.

6. The method for preparing the high-performance antimony-based electrode material as described in claim 1, characterized in that, The organophosphorus compound is at least one of triphenylphosphine, triethyl phosphate, and tri-n-octylphosphine.

7. The method for preparing the high-performance antimony-based electrode material as described in claim 1, characterized in that, The temperature for chemical vapor deposition is 350-450℃.

8. The method for preparing the high-performance antimony-based electrode material as described in claim 1, characterized in that, The nitrogen-sulfur co-doped porous carbon shell is made of a carbon source precursor, a nitrogen-sulfur dual doping source, and a pore-forming agent in a mass ratio of 1:0.2-0.3:0.25-0.

35.

9. The method for preparing the high-performance antimony-based electrode material as described in claim 8, characterized in that, The nitrogen-sulfur dual doping source is at least one of thiourea, cysteine, and methionine.

10. A high-performance antimony-based electrode material, characterized in that, The high-performance antimony-based electrode material is prepared by the method described in any one of claims 1-9.

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