A negative electrode material for a sodium ion battery with a cyanamide zinc / zinc sulfide heterostructure, a preparation method and application thereof, and a sodium ion battery

Abstract

The application discloses a kind of negative electrode materials with cyanamide zinc / zinc sulfide heterostructure for sodium ion battery and its preparation method and application, sodium ion battery, it is related to sodium battery technical field.The negative electrode material of the present application is with cyanamide zinc as core, zinc sulfide as outer protective shell spherical particle, the negative electrode material can provide 300~900 mAh / g reversible specific capacity, can be realized at 10 A / g high current density rate discharge and 300~3000 cycle life.The application also provides the preparation method of the negative electrode material, mainly cyanamide salt and zinc salt are used as reaction raw materials, obtained by using precipitation method in combination with low temperature reaction, this method discards the use of dangerous chemical reagent, experiment is carried out under normal pressure, and the sodium ion negative electrode material prepared has the advantages, such as controllable core-shell structure, stable electrochemical performance, can be used in electrochemical sodium ion energy storage field.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of sodium battery, in particular to a negative electrode material for sodium ion battery with a cyanamide zinc / zinc sulfide heterostructure, a preparation method and application thereof, and a sodium ion battery. BACKGROUND

[0002] With the development of renewable energy and electric transportation, the demand for efficient, safe and low-cost energy storage systems is increasingly urgent. Although lithium-ion batteries have been widely used in portable electronic devices and electric vehicles, due to the limited reserves of lithium resources, the rising prices and uneven geographical distribution, the sustainability of lithium-ion batteries in large-scale energy storage has been severely restricted. Sodium-ion batteries are becoming one of the promising technology routes to replace or complement lithium batteries due to the abundant resources of sodium, low cost and similar electrochemical properties to lithium.

[0003] In the sodium-ion battery system, the negative electrode material plays a key role in the overall performance of the battery. In recent years, the research on negative electrode materials focuses on overcoming the problems of kinetic lag and volume expansion caused by the large radius of sodium ions. At present, the negative electrode material systems that are studied more include hard carbon, metal oxide / sulfide and alloy type materials. Among them, hard carbon material, as the most promising negative electrode for commercialization, has a reversible specific capacity of 250-300 mAh / g. Through pore regulation and surface functional group modification, the first cycle coulombic efficiency can be improved to more than 88%, and it has good cycle life. However, the problem of hard carbon is poor rate performance and the risk of sodium precipitation at a deep charge condition at a very low voltage platform (close to 0 V). In contrast, metal oxide / sulfide and alloy type materials (such as Sn, Sb and Bi) have higher theoretical capacity, but such materials generally have serious volume expansion, structure pulverization and poor cycle stability problems during the sodium ion intercalation and deintercalation process. For example, although the layered transition metal sulfide MoS2 has a high capacity of 400-600 mAh / g, the cycle stability is usually less than 500 times; and tin, antimony and other alloy type metals have a volume expansion rate of more than 300% during charging and discharging, causing serious mechanical stress and electrode cracking, which limits the long cycle performance. Therefore, developing new negative electrode materials with high capacity, high rate performance and excellent structure stability is of great significance to promote the development of sodium-ion batteries.

[0004] The main technical challenges faced by current sodium-ion battery negative electrode materials include: 1. How to effectively inhibit the volume effect and structure collapse of high-capacity materials; 2. How to optimize the electrode / electrolyte interface stability and build a uniform and stable SEI film; 3. How to realize low-cost, controllable and scalable preparation of materials. Future development trends will focus on multi-scale collaborative design strategies, including atomic-level doping-nanostructure-micromorphology, to promote the comprehensive performance improvement of sodium battery negative electrode materials.

[0005] In recent years, transition metal cyanamide compounds have been widely concerned due to their high theoretical specific capacity, low polarization and good reaction kinetics. However, such materials still face problems such as irreversible structural change during the charging and discharging process, poor conductivity and rapid capacity decay. In order to overcome the above challenges, it has been proved that constructing a heterostructure is a feasible and effective strategy. The heterostructure can effectively promote the rapid migration of electrons / ions, enhance the structural stability and improve the overall electrochemical performance by regulating the interface structure and electronic state of the material. However, there is a lack of a simple and effective in-situ construction method for such materials. SUMMARY

[0006] In view of the above problems, the present application provides a sodium-ion battery negative electrode material with cyanamide zinc / zinc sulfide heterostructure, a preparation method and application thereof, and a sodium-ion battery. The negative electrode material has the characteristics of controllable core-shell structure, stable electrochemical performance and simple preparation process, and can be applied to the field of electrochemical sodium-ion energy storage. The specific technical solutions are as follows:

[0007] A sodium-ion battery negative electrode material with cyanamide zinc / zinc sulfide heterostructure, wherein the negative electrode material is a spherical particle formed by taking cyanamide zinc as the inner core and taking zinc sulfide as the outer protective shell; the particle size diameter of the particle is controllable in the range of 50-1000 nm, and the thickness of the outer protective shell is adjustable in the range of 2-100 nm.

[0008] The present application also provides a preparation method of the above-mentioned sodium-ion battery negative electrode material with cyanamide zinc / zinc sulfide heterostructure, comprising the following steps:

[0009] (1) Dissolve cyanamide salt and zinc salt in water, mix uniformly, then add a precipitant solution, and perform a precipitation reaction at 20-120℃ for 0.5-48h to obtain cyanamide zinc; disperse the cyanamide zinc into an organic solvent to prepare a cyanamide zinc solution with a concentration of 0.01-1 M;

[0010] (2) Add a sulfur-containing compound aqueous solution to the cyanamide zinc solution, and perform an ion exchange reaction at 30-180℃ for 0.5-48h, wherein the concentration of the sulfur-containing compound aqueous solution is 0.02-1 M, the volume ratio of the cyanamide zinc solution to the sulfur-containing compound aqueous solution is (0.2-10):1, and the ion exchange reaction is performed by liquid stirring method, solvothermal method or sol-gel method, thereby obtaining the sodium-ion battery negative electrode material with cyanamide zinc / zinc sulfide heterostructure.

[0011] Preferably, the cyanamide salt is selected from one or more of monocyamide, dicyamide, cyanuric acid and sodium bicarbonate cyanamide; and the concentration of the cyanamide salt aqueous solution is 0.05-2 M.

[0012] Preferably, the zinc salt is selected from one or more of zinc chloride, zinc nitrate, zinc acetate and zinc sulfate; the concentration of the aqueous solution of the zinc salt is 0.02-2 M.

[0013] Preferably, the precipitant in the precipitant solution is selected from one or more of benzylamine, ethanolamine, triethanolamine, oleylamine and ammonia; the concentration of the precipitant solution is 0.1-5 M.

[0014] Preferably, the molar ratio of the zinc salt and the cyanamide salt is 1:(1-50), preferably 1:(5-20); the molar ratio of the zinc salt and the hydroxyl ion in the precipitant solution is 1:(0.1-50), preferably 1:(1-3).

[0015] Preferably, the organic solvent is selected from one or more of ethylene glycol, ethanolamine, N-methylpyrrolidone, dimethylformamide and dimethyl sulfoxide.

[0016] Preferably, the sulfur-containing compound is selected from one or more of thiourea, thioacetamide, sodium sulfide, thioacetic acid and L-cysteine.

[0017] The application also provides a sodium ion battery comprising the above negative electrode material.

[0018] The application also provides application of the above negative electrode material with a cyanamide zinc / zinc sulfide heterostructure to sodium ion batteries.

[0019] Compared with the prior art, the application has the following beneficial effects:

[0020] 1. The application uses cyanamide salt and zinc salt as raw materials, and uses a precipitation method combined with low-temperature reaction to obtain a negative electrode material with a cyanamide zinc / zinc sulfide heterostructure for sodium ion batteries. The negative electrode material has the characteristics of controllable core-shell structure and stable electrochemical performance, and can be applied to the field of electrochemical sodium ion energy storage. The negative electrode material can provide a reversible specific capacity of 300-900 mAh / g, realize rate discharge at a high current density of 10 A / g, and has a cycle life of 300-3000 times.

[0021] 2. The preparation method of the application does not use dangerous chemical reagents, and the experimental process can be carried out at normal pressure. The preparation process is simple, the cost is low, and the application is suitable for promotion. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiment description.

[0023] Figure 1SEM morphology of the sodium ion negative electrode material with cyanamide zinc / sulfurized zinc heterostructure prepared in Example 1 of the present application;

[0024] Figure 2 Specific capacity and coulombic efficiency of the sodium ion negative electrode material with cyanamide zinc / sulfurized zinc heterostructure prepared in Example 1 of the present application under different current densities;

[0025] Figure 3 Specific capacity and coulombic efficiency of the sodium ion negative electrode material with cyanamide zinc / sulfurized zinc heterostructure prepared in Example 1 of the present application under 1 A g -1

[0026] Figure 4 Specific capacity and coulombic efficiency of the sodium ion negative electrode material with cyanamide zinc prepared in Comparative Example 1 of the present application under different current densities;

[0027] Figure 5 Specific capacity and coulombic efficiency of the sodium ion negative electrode material with cyanamide zinc prepared in Comparative Example 1 of the present application under 1 A g -1

[0028] Figure 6 Schematic diagram of the sodium ion negative electrode material with cyanamide zinc / sulfurized zinc heterostructure prepared in the present application. DETAILED DESCRIPTION

[0029] The specific embodiments of the present application are described in detail below, but it should be understood that the scope of protection of the present application is not limited by the specific embodiments.

[0030] The present application discloses a preparation method of a sodium ion negative electrode material with cyanamide zinc / sulfurized zinc heterostructure. Cyanamide salt and zinc salt are used as raw materials for reaction, a precipitant is introduced, and cyanamide zinc is obtained after a certain time of reaction by using a precipitation method. The cyanamide zinc is dispersed into an organic solvent, a sulfur-containing compound is introduced, and ion exchange reaction is performed to obtain a sodium ion negative electrode material with cyanamide zinc / sulfurized zinc heterostructure (as shown in FIG. 1). Figure 6

[0031] In an optional embodiment, the cyanamide salt is selected from one or more of monocyamide, dicyamide, cyanuric acid, and sodium bicarbonate cyanamide, and the concentration of the cyanamide salt aqueous solution is 0.05-2 M;

[0032] The zinc salt is selected from one or more of zinc chloride, zinc nitrate, zinc acetate, and zinc sulfate, and the concentration of the zinc salt aqueous solution is 0.02-2 M;

[0033] The precipitant used in the precipitation method is selected from one or more of benzylamine, ethanolamine, triethanolamine, oleylamine, and ammonia water, and the concentration of the precipitant solution is 0.1-5 M;

[0034] ​​​The molar ratio of the zinc salt and the cyanamide salt is 1:(1-50), preferably 1:(5-20); the molar ratio of the zinc salt and the hydroxyl ions of the precipitant is 1:(0.1-50), preferably 1:(1-3);

[0035] The temperature of the precipitation reaction is 20-120℃, and the reaction time is 0.5-48h;

[0036] The organic solvent is selected from one or more of ethylene glycol, ethanolamine, N-methyl pyrrolidone, dimethylformamide and dimethyl sulfoxide;

[0037] The concentration of the zinc cyanamide is 0.01-1 M;

[0038] The sulfur-containing compound is selected from one or more of thiourea, thioacetamide, sodium sulfide, thioacetic acid and L-cysteine, and the concentration of the sulfur-containing compound is 0.02-1 M;

[0039] The volume ratio of the zinc cyanamide solution to the sulfur-containing compound solution is (0.2-10):1;

[0040] The ion exchange reaction is carried out by liquid stirring method, solvothermal method or sol-gel method.

[0041] The temperature of the ion exchange reaction is 30-180℃, and the reaction time is 0.5-48h.

[0042] The sodium ion negative electrode material with zinc cyanamide / zinc sulfide heterostructure of the application has good chemical stability and excellent electrochemical properties, and can be applied in the field of sodium ion batteries.

[0043] The following further examples are further illustrated to explain the application in detail. It should also be understood that the following examples are only used to further illustrate the application, and cannot be understood as limiting the protection scope of the application. Some non-essential improvements and adjustments made by those skilled in the art according to the above content of the application all belong to the protection scope of the application. The specific process parameters in the following examples are only one example in the appropriate range, i.e. those skilled in the art can select within the appropriate range through the description herein, and are not limited to the specific values in the following examples.

[0044] Example 1

[0045] The zinc salt and the cyanamide salt are dissolved in water according to a molar ratio of 1:10, and the two are mixed and stirred. The cyanamide salt is monocyamide, and the aqueous solution has a concentration of 0.2 M; the zinc salt is zinc chloride, and the aqueous solution has a concentration of 0.02 M. Benzylamine is used as a precipitant. The molar ratio of the zinc salt to the hydroxyl ion of the precipitant is 1:2, and the solution concentration of the precipitant is 0.2 M; the precipitant is dropped into the above-mentioned mixed solution at 60°C, and the reaction time is 0.5 h. Finally, the prepared cyanamide zinc is dispersed in an ethylene glycol solution with a concentration of 0.02 M; thiourea is dropped into the cyanamide zinc solution to perform an ion exchange reaction, the concentration of the thiourea is 0.08 M, the volume ratio of the cyanamide zinc solution to the thiourea solution is 1:1, the reaction temperature is 100°C, and the reaction time is 1 h. Finally, a sodium ion negative electrode material with a cyanamide zinc / zinc sulfide heterostructure is obtained, the average diameter of the negative electrode particles is 1000 nm, Figure 1 , the average thickness of the ZnS shell is 2 nm, the capacity of the negative electrode material reaches 734 mAh / g, the discharge capacity is 178 mAh / g at a current density of 10 A / g, Figure 2 , and the capacity retention rate is 78% after 377 cycles at a current of 1 A / g, Figure 3 , wherein the initial data of Figure 3 are 786.2 mAh / g.

[0046] Comparative Example 1

[0047] The zinc salt and the cyanamide salt are dissolved in water according to a molar ratio of 1:10, and the two are mixed and stirred. The cyanamide salt is monocyamide, and the aqueous solution has a concentration of 0.2 M; the zinc salt is zinc chloride, and the aqueous solution has a concentration of 0.02 M. Benzylamine is used as a precipitant. The molar ratio of the zinc salt to the hydroxyl ion of the precipitant is 1:2, and the solution concentration of the precipitant is 0.2 M; the precipitant is dropped into the above-mentioned mixed solution at 60°C, and the reaction time is 0.5 h. Finally, the prepared cyanamide zinc negative electrode particles have an average diameter of 1600 nm, the capacity of the negative electrode material reaches 338 mAh / g, the discharge capacity is 100 mAh / g at a current density of 10 A / g, Figure 4 , and the capacity retention rate is 45% after 377 cycles at a current of 1 A / g, Figure 5 , wherein the initial data of Figure 5 are 445.3 mAh / g.

[0048] It can be known from Example 1 and Comparative Example 1 that the sodium ion negative electrode material with a cyanamide zinc / zinc sulfide heterostructure prepared in the present application exhibits higher specific capacity and cycle life in a sodium ion battery.

[0049] Example 2

[0050] The zinc salt and the cyanamide salt are dissolved in water in a molar ratio of 1:6, and the two are mixed and stirred. The cyanamide salt is a mixture of monocyamide and dicyamide, and the aqueous solution has a concentration of 0.5 M; the zinc salt is zinc chloride and zinc nitrate, and the aqueous solution has a concentration of 0.5 M. Benzylamine and ethanolamine are used as precipitants. The molar ratio of the zinc salt to the hydroxyl ion of the precipitant is 1:2, and the concentration of the precipitant solution is 0.5 M; the precipitant is dropped into the above-mentioned mixed solution at 50°C, and the reaction time is 2 h. Finally, the prepared cyanamide zinc is dispersed in an ethylene glycol solution with a concentration of 0.05 M; a mixture of thiourea and thioacetamide is dropped into the cyanamide zinc solution to perform ion exchange reaction, the concentration of the sulfur-containing compound is 0.08 M, the volume ratio of the cyanamide zinc solution to the sulfur-containing compound solution is 0.5:1, the reaction temperature is 80°C, and the reaction time is 3 h. Finally, a sodium ion negative electrode material with a cyanamide zinc / zinc sulfide heterostructure is obtained, the average diameter of the negative electrode particles is 500 nm, the thickness of the ZnS shell is 5 nm, the capacity of the negative electrode material reaches 690 mAh / g, the discharge capacity at a current density of 10 A / g is 300 mAh / g, and the capacity retention rate after 1000 cycles is 85%.

[0051] Example 3

[0052] The zinc salt and the cyanamide salt are dissolved in water in a molar ratio of 1:6, and the two are mixed and stirred. The cyanamide salt is a mixture of monocyamide and dicyamide, and the aqueous solution has a concentration of 0.5 M; the zinc salt is zinc chloride and zinc nitrate, and the aqueous solution has a concentration of 0.5 M. Benzylamine and ethanolamine are used as precipitants. The molar ratio of the zinc salt to the hydroxyl ion of the precipitant is 1:2, and the concentration of the precipitant solution is 0.5 M; the precipitant is dropped into the above-mentioned mixed solution at 50°C, and the reaction time is 2 h. Finally, the prepared cyanamide zinc is dispersed in an ethylene glycol solution with a concentration of 0.05 M; a mixture of thiourea and thioacetamide is dropped into the cyanamide zinc solution to perform ion exchange reaction, the concentration of the sulfur-containing compound is 0.08 M, the volume ratio of the cyanamide zinc solution to the sulfur-containing compound solution is 0.5:1, the reaction temperature is 80°C, and the reaction time is 3 h. Finally, a sodium ion negative electrode material with a cyanamide zinc / zinc sulfide heterostructure is obtained, the average diameter of the negative electrode particles is 500 nm, the thickness of the ZnS shell is 5 nm, the capacity of the negative electrode material reaches 690 mAh / g, the discharge capacity at a current density of 10 A / g is 300 mAh / g, and the capacity retention rate after 1000 cycles is 85%.

[0053] Example 4

[0054] The zinc salt and the cyanamide salt are dissolved in water in a molar ratio of 1:8, and the two are mixed and stirred. The cyanamide salt is a mixture of cyanuric acid and sodium bicarbonitrile, and the aqueous solution has a concentration of 1 M; the zinc salt uses zinc nitrate and zinc acetate, and the aqueous solution has a concentration of 0.8 M. Triethanolamine is used as the precipitant. The molar ratio of zinc salt to hydroxyl ions of precipitant is 1:7, and the concentration of precipitant solution is 0.1 M; the precipitant is dropped into the above-mentioned mixed solution at 90°C, and the reaction time is 10 h. Finally, the prepared cyanamide zinc is dispersed in an ethanolamine solution with a concentration of 0.02 M; a mixture of sodium sulfide and thioacetic acid is dropped into the cyanamide zinc solution, and an ion exchange reaction is carried out by a solvothermal method, the concentration of sulfur-containing compounds is 0.2 M, the volume ratio of cyanamide zinc solution to sulfur-containing compound solution is 5:1, the reaction temperature is 150°C, and the reaction time is 5 h. Finally, a sodium ion negative electrode material with a cyanamide zinc / zinc sulfide heterostructure is obtained, the average diameter of the negative electrode particles is 300 nm, the thickness of the ZnS shell is 4 nm, the capacity of the negative electrode material reaches 890 mAh / g, the discharge capacity at a current density of 10 A / g is 480 mAh / g, and the capacity retention rate after 1000 cycles is 81%.

[0055] Example 5

[0056] The zinc salt and the cyanamide salt are dissolved in water in a molar ratio of 1:40, and the two are mixed and stirred. The cyanamide salt is sodium bicarbonitrile, and the aqueous solution has a concentration of 1 M; the zinc salt uses zinc nitrate, zinc sulfate, and zinc acetate, and the aqueous solution has a concentration of 2 M. Ammonia is used as the precipitant. The molar ratio of zinc salt to hydroxyl ions of precipitant is 1:30, and the concentration of precipitant solution is 0.2 M; the precipitant is dropped into the above-mentioned mixed solution at 30°C, and the reaction time is 40 h. Finally, the prepared cyanamide zinc is dispersed in an ethanolamine solution with a concentration of 0.1 M; L-cysteine is dropped into the cyanamide zinc solution, and an ion exchange reaction is carried out by a sol-gel method, the concentration of sulfur-containing compounds is 0.4 M, the volume ratio of cyanamide zinc solution to sulfur-containing compound solution is 0.2:1, the reaction temperature is 30°C, and the reaction time is 40 h. Finally, a sodium ion negative electrode material with a cyanamide zinc / zinc sulfide heterostructure is obtained, the average diameter of the negative electrode particles is 300 nm, the thickness of the ZnS shell is 2 nm, the capacity of the negative electrode material reaches 850 mAh / g, the discharge capacity at a current density of 10 A / g is 400 mAh / g, and the capacity retention rate after 3000 cycles is 85%.

[0057] In summary, the application uses cyanamide salt and zinc salt as reaction raw materials, and uses a precipitation method combined with a low-temperature reaction to obtain a negative electrode material for a sodium ion battery with a cyanamide zinc / zinc sulfide heterostructure, the negative electrode material has the characteristics of controllable core-shell structure and stable electrochemical performance, and can be applied to the field of electrochemical sodium ion energy storage. The negative electrode material can provide a reversible specific capacity of 300-900 mAh / g, realize rate discharge at a high current density of 10 A / g, and has a cycle life of 300-3000 times. Meanwhile, the preparation method of the application discards the use of dangerous chemical reagents, the experimental process can be carried out at normal pressure, the preparation process is simple, the cost is low, and the application is suitable for promotion.

[0058] The foregoing description of specific exemplary embodiments of the application is intended to be illustrative only and is not intended to limit the application to the precise forms described. Many modifications and variations are possible in light of the above teachings without departing from the spirit or essential characteristics of the application. The exemplary embodiments were chosen and described in order to explain the principles of the application and its practical application and to allow others skilled in the art to understand the application for various exemplary embodiments with various modifications being applicable. The scope of the application is intended to be defined by the claims and their equivalents.

Claims

1. A method for preparing a negative electrode material for sodium-ion batteries having a zinc cyanamide / zinc sulfide heterostructure, characterized in that, The negative electrode material is a spherical particle formed with zinc cyanamide as the core and zinc sulfide as the outer protective shell; the particle diameter is controllable in the range of 50~1000 nm, and the thickness of the outer protective shell is adjustable in the range of 2~100 nm; the specific preparation method includes the following steps: (1) After dissolving cyanamide salt and zinc salt in water and mixing them, a precipitant solution is added, and a precipitation reaction is carried out at 20-120℃ for 0.5-48h to obtain zinc cyanamide; the zinc cyanamide is dispersed in an organic solvent to prepare a zinc cyanamide solution with a concentration of 0.01-1 M. (2) Add an aqueous solution of sulfur-containing compound to the zinc cyanamide solution and carry out an ion exchange reaction at 30-180°C for 0.5-48 h. The concentration of the aqueous solution of sulfur-containing compound is 0.02-1 M and the volume ratio of the zinc cyanamide solution to the aqueous solution of sulfur-containing compound is (0.2-10):1, thereby obtaining the negative electrode material for sodium-ion batteries with zinc cyanamide / zinc sulfide heterostructure.

2. The method for preparing a negative electrode material for sodium-ion batteries with a zinc cyanamide / zinc sulfide heterostructure according to claim 1, characterized in that, The cyanamide salt is selected from one or more of monocyanamide, dicyandiamide, cyanuric acid, and sodium bicarbonate; the concentration of the aqueous solution of the cyanamide salt is 0.05~2M.

3. The method for preparing a negative electrode material for sodium-ion batteries with a zinc cyanamide / zinc sulfide heterostructure according to claim 1, characterized in that, The zinc salt is selected from one or more of zinc chloride, zinc nitrate, zinc acetate, and zinc sulfate; the concentration of the aqueous solution of the zinc salt is 0.02~2 M.

4. The method for preparing a negative electrode material for sodium-ion batteries with a zinc cyanamide / zinc sulfide heterostructure according to claim 1, characterized in that, The precipitant in the precipitant solution is selected from one or more of benzylamine, ethanolamine, triethanolamine, oleylamine, and ammonia water; the concentration of the precipitant solution is 0.1~5 M.

5. The method for preparing a negative electrode material for sodium-ion batteries with a zinc cyanamide / zinc sulfide heterostructure according to claim 1, characterized in that, The molar ratio of the zinc salt to the cyanamide salt is 1:(1-50); the molar ratio of the zinc salt to the hydroxide ions in the precipitant solution is 1:(0.1-50).

6. The method for preparing a negative electrode material for sodium-ion batteries with a zinc cyanamide / zinc sulfide heterostructure according to claim 1, characterized in that, The organic solvent is selected from one or more of ethylene glycol, ethanolamine, N-methylpyrrolidone, dimethylformamide, and dimethyl sulfoxide.

7. The method for preparing a negative electrode material for sodium-ion batteries with a zinc cyanamide / zinc sulfide heterostructure according to claim 1, characterized in that, The sulfur-containing compound is selected from one or more of thiourea, thioacetamide, sodium sulfide, thioacetic acid, and L-cysteine.

8. A sodium-ion battery, characterized in that, The sodium-ion battery includes a negative electrode material for sodium-ion batteries with a zinc cyanamide / zinc sulfide heterostructure prepared by the preparation method according to any one of claims 1 to 7.

9. The application of a sodium-ion battery anode material with a zinc cyanamide / zinc sulfide heterostructure prepared by the preparation method according to any one of claims 1 to 7 in the field of sodium-ion batteries.

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