Negative electrode material with zinc cyanamide / zinc sulfide heterostructure for sodium-ion battery, preparation method and application of negative electrode material, and sodium-ion battery

Abstract

The invention discloses a negative electrode material with a zinc cyanamide / zinc sulfide heterostructure for a sodium ion battery, a preparation method and application of the negative electrode material and the sodium ion battery, and relates to the technical field of sodium batteries. The negative electrode material provided by the invention is a spherical particle with zinc cyanamide as an inner core and zinc sulfide as an outer protective shell, can provide a reversible specific capacity of 300-900 mAh / g, and can realize rate discharge under a high current density of 10 A / g and a cycle life of 300-3000 times. The invention also provides a preparation method of the negative electrode material, cyanamide salt and zinc salt are mainly used as reaction raw materials, the negative electrode material is obtained by combining a precipitation method with a low-temperature reaction, the method abandons the use of hazardous chemical reagents, the experiment process is carried out under normal pressure, and the cost is low. And the prepared sodium ion negative electrode material has the advantages of controllable core-shell structure, stable electrochemical performance and the like, and can be used in the field of electrochemical sodium ion energy storage.

Description

Technical Field

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

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

[0003] In sodium-ion batteries (SIBs), anode materials play a critical role in overall battery performance. In recent years, anode material research has focused on overcoming the kinetic hysteresis and volume expansion issues caused by the large radius of sodium ions. Currently, the most studied anode material systems include hard carbon, metal oxides / sulfides, and alloys. Hard carbon, the anode with the greatest commercial potential, typically offers a reversible specific capacity of 250-300 mAh / g. Through pore manipulation and surface functional group modification, its first-cycle coulombic efficiency can be increased to over 88%, while also exhibiting excellent cycle life. However, challenges with hard carbon include poor rate capability and the risk of sodium precipitation at very low voltages (near 0 V) ​​under deep charging conditions. In contrast, metal oxides / sulfides and alloys (such as Sn, Sb, and Bi) offer higher theoretical capacities, but these materials generally suffer from severe volume expansion, structural pulverization, and poor cycling stability during Na-ion insertion and extraction. For example, although layered transition metal sulfides MoS2 have a high capacity of 400-600 mAh / g, their cycling stability is typically less than 500 cycles. Meanwhile, alloy metals such as tin and antimony can experience volume expansion rates exceeding 300% during charge and discharge, causing severe mechanical stress and electrode cracking, limiting their long-cycle performance. Therefore, developing new anode materials that combine high capacity, high rate performance, and excellent structural stability is of great significance for promoting the development of sodium-ion batteries.

[0004] The main technical challenges facing sodium-ion battery anode materials currently include: 1. How to effectively suppress the volume effect and structural collapse of high-capacity materials; 2. How to optimize the stability of the electrode / electrolyte interface and construct a uniform and stable SEI film; and 3. How to achieve low-cost, controllable, and scalable material preparation. Future development trends will focus on multi-scale collaborative design strategies, including atomic-level doping, nanostructuring, and micron-scale morphology, to promote the comprehensive performance improvement of sodium-ion battery anode materials.

[0005] In recent years, transition metal cyanamide compounds have attracted widespread attention due to their high theoretical specific capacity, low polarization and good reaction kinetics. However, this type of material still faces problems such as irreversible structural changes during the reaction, poor conductivity and rapid capacity decay during the charge and discharge process. In order to overcome the above challenges, constructing heterostructures has been proven to be a feasible and effective strategy. Heterostructures can effectively promote the rapid migration of electrons / ions, enhance structural stability and improve 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 heterostructures for this type of material. Summary of the Invention

[0006] To address the above shortcomings, the present invention provides a negative electrode material for sodium ion batteries having a zinc cyanamide / zinc sulfide heterostructure, a preparation method and application thereof, and a sodium ion battery. This negative electrode material has the characteristics of controllable core-shell structure, stable electrochemical performance, and a simple preparation process, and can be applied to the field of electrochemical sodium ion energy storage. The specific technical solution is as follows: A negative electrode material for sodium ion batteries having a zinc cyanamide / zinc sulfide heterostructure. The negative electrode material comprises spherical particles with a zinc cyanamide core and a zinc sulfide outer protective shell. The particle diameter of the particles can be controlled within a range of 50 to 1000 nm, and the thickness of the outer protective shell can be adjusted to 2 to 100 nm.

[0007] The present invention also provides a method for preparing the above-mentioned negative electrode material for sodium ion batteries having a zinc cyanamide / zinc sulfide heterostructure, comprising the following steps: (1) dissolving a cyanamide salt and a zinc salt in water and mixing them uniformly, adding a precipitant solution, and performing a precipitation reaction at 20 to 120° C. for 0.5 to 48 hours to obtain zinc cyanamide; dispersing the zinc cyanamide in an organic solvent to prepare a zinc cyanamide solution with a concentration of 0.01 to 1 M; (2) Adding an aqueous solution of a sulfur-containing compound to the zinc cyanamide solution, and performing an ion exchange reaction at 30-180° C. for 0.5-48 h, wherein the concentration of the aqueous solution of the sulfur-containing compound is 0.02-1 M, and the volume ratio of the zinc cyanamide solution to the aqueous solution of the sulfur-containing compound is (0.2-10):1, and the ion exchange reaction is carried out by a liquid phase stirring method, a solvent thermal method or a sol-gel method, thereby obtaining the negative electrode material for a sodium ion battery having a zinc cyanamide / zinc sulfide heterostructure.

[0008] Preferably, the cyanamide salt is selected from one or more of monocyanamide, dicyandiamide, cyanuric acid and sodium cyanamide bicarbonate; and the concentration of the aqueous solution of the cyanamide salt is 0.05-2 M.

[0009] Preferably, the zinc salt is selected from one or more of zinc chloride, zinc nitrate, zinc acetate and zinc sulfate; and the concentration of the aqueous solution of the zinc salt is 0.02-2 M.

[0010] Preferably, the precipitant in the precipitant solution 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.

[0011] Preferably, the molar ratio of the zinc salt to the cyanamide salt is 1:(1-50), preferably 1:(5-20); the molar ratio of the zinc salt to the hydroxide ions of the precipitant solution is 1:(0.1-50), preferably 1:(1-3).

[0012] Preferably, the organic solvent is selected from one or more of ethylene glycol, ethanolamine, N-methylpyrrolidone, dimethylformamide and dimethyl sulfoxide.

[0013] Preferably, the sulfur-containing compound is selected from one or more of thiourea, thioacetamide, sodium sulfide, thioacetic acid and L-cysteine.

[0014] The present invention also provides a sodium ion battery, which includes the above-mentioned negative electrode material.

[0015] The present invention also provides an application of the above-mentioned negative electrode material for sodium ion batteries having a zinc cyanamide / zinc sulfide heterostructure in the field of sodium ion batteries.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention uses cyanamide salts and zinc salts as reaction raw materials, and utilizes a precipitation method combined with a low-temperature reaction to obtain a negative electrode material for sodium ion batteries having a cyanamide zinc / zinc sulfide heterostructure. This negative electrode material has the characteristics of a controllable core-shell structure and stable electrochemical performance, and can be applied to the field of electrochemical sodium ion energy storage. Specifically, this negative electrode material can provide a reversible specific capacity of 300-900 mAh / g, achieve a high rate discharge at a high current density of 10 A / g, and a cycle life of 300-3000 times.

[0017] 2. The preparation method of the present invention abandons the use of hazardous chemical reagents, the experimental process can be carried out under normal pressure, the preparation process is simple, the cost is low, and it is suitable for promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments.

[0019] Figure 1 This is an SEM morphology image of the sodium ion negative electrode material having a zinc cyanamide / zinc sulfide heterostructure prepared in Example 1 of the present invention; Figure 2 Specific capacity and coulombic efficiency of the sodium ion negative electrode material having a zinc cyanamide / zinc sulfide heterostructure prepared in Example 1 of the present invention at different current densities; Figure 3 The sodium ion negative electrode material with zinc cyanamide / zinc sulfide heterostructure prepared in Example 1 of the present invention is -1 Specific capacity and Coulombic efficiency diagram below; Figure 4 Specific capacity and coulombic efficiency diagram of the negative electrode material with sodium zinc cyanamide ion prepared in Comparative Example 1 of the present invention at different current densities; Figure 5 The negative electrode material with sodium zinc cyanamide ion prepared in comparative example 1 of the present invention is 1 A g -1 Specific capacity and Coulombic efficiency diagram below; Figure 6 Schematic diagram of the preparation of sodium ion negative electrode materials with zinc cyanamide / zinc sulfide heterostructures according to the present invention. DETAILED DESCRIPTION

[0020] The specific embodiments of the present invention are described in detail below, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments.

[0021] The present invention discloses a method for preparing a sodium ion negative electrode material having a zinc cyanamide / zinc sulfide heterostructure, wherein cyanamide salt and zinc salt are used as reaction raw materials, a precipitant is introduced, and a precipitation method is used to react for a certain period of time to obtain zinc cyanamide. Zinc cyanamide is dispersed in an organic solvent, a sulfur-containing compound is introduced, and an ion exchange reaction is performed to obtain a sodium ion negative electrode material having a zinc cyanamide / zinc sulfide heterostructure (such as Figure 6 shown).

[0022] In an optional embodiment, the cyanamide salt is selected from one or more of monocyanamide, dicyandiamide, cyanuric acid and sodium bicarbonate cyanamide, and the concentration of the cyanamide salt aqueous solution is 0.05 to 2 M; 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; The precipitation method uses a precipitant 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; The molar ratio of the zinc salt to the cyanamide salt is 1:(1-50), preferably 1:(5-20); the molar ratio of the zinc salt to the hydroxide ion of the precipitant is 1:(0.1-50), preferably 1:(1-3); The precipitation reaction temperature is 20-120°C, and the reaction time is 0.5-48h; The organic solvent is selected from one or more of ethylene glycol, ethanolamine, N-methylpyrrolidone, dimethylformamide and dimethyl sulfoxide; The concentration of the zinc cyanamide is 0.01~1 M; 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 to 1 M; The volume ratio of the zinc cyanamide solution to the sulfur-containing compound solution is (0.2-10):1; The ion exchange reaction is carried out in a liquid phase stirring method, a solvent thermal method or a sol-gel method.

[0023] The temperature of the ion exchange reaction is 30-180° C., and the reaction time is 0.5-48 hours.

[0024] The sodium ion negative electrode material with a zinc cyanamide / zinc sulfide heterostructure of the present invention has good chemical stability and excellent electrochemical properties, and can be applied to the field of sodium ion batteries.

[0025] The following examples are further given to illustrate the present invention in detail. It should also be understood that the following examples are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above content of the present invention all fall within the scope of protection of the present invention. The specific process parameters and the like in the following examples are only examples within a suitable range, that is, those skilled in the art can make selections within a suitable range through the description herein, and are not limited to the specific numerical values ​​exemplified below.

[0026] Example 1 Zinc salt and cyanamide salt were dissolved in water at a molar ratio of 1:10, and the two were mixed and stirred. The cyanamide salt was monocyanamide, and the concentration of the aqueous solution was 0.2M; the zinc salt was zinc chloride, and the concentration of the aqueous solution was 0.02M. Benzylamine was used as the precipitant. The molar ratio of the hydroxide ions of the zinc salt to the precipitant was 1:2, and the concentration of the precipitant solution was 0.2 M. The precipitant was added dropwise to the above mixed solution at 60°C for a reaction time of 0.5h. Finally, the prepared zinc cyanamide was dispersed in an ethylene glycol solution with a concentration of 0.02 M. Thiourea was added dropwise to the zinc cyanamide solution for an ion exchange reaction. The thiourea concentration was 0.08 M, the volume ratio of the zinc cyanamide solution to the thiourea solution was 1:1, the reaction temperature was 100°C, and the reaction time was 1h. Finally, a sodium ion negative electrode material with a zinc cyanamide / zinc sulfide heterostructure was obtained, and the average diameter of the negative electrode particles was 1000 nm ( Figure 1 ), the average thickness of the ZnS shell is 2nm, the capacity of the negative electrode material is 734mAh / g, and the discharge capacity is 178mAh / g at a current density of 10A / g ( Figure 2), the capacity retention rate was 78% after 377 cycles at 1A / g ( Figure 3 ,in Figure 3 The starting data is 786.2 mAh / g).

[0027] Comparative Example 1 Zinc salt and cyanamide salt were dissolved in water at a molar ratio of 1:10, and the two were mixed and stirred. The cyanamide salt was monocyanamide, and the concentration of the aqueous solution was 0.2M; the zinc salt was zinc chloride, and the concentration of the aqueous solution was 0.02M. Benzylamine was used as a precipitant. The molar ratio of the hydroxide ions of the zinc salt to the precipitant was 1:2, and the concentration of the precipitant solution was 0.2 M. The precipitant was added dropwise to the above mixed solution at 60°C for 0.5h. The average diameter of the cyanamide zinc negative electrode particles finally prepared was 1600nm. The capacity of the negative electrode material reached 338 mAh / g, and the discharge capacity was 100 mAh / g at a current density of 10A / g ( Figure 4 ), the capacity retention rate is 45% after 377 cycles at 1A / g ( Figure 5 ,in Figure 5 The starting data is 445.3 mAh / g).

[0028] It can be seen from Example 1 and Comparative Example 1 that the sodium ion negative electrode material having a zinc cyanamide / zinc sulfide heterostructure prepared by the present invention exhibits higher specific capacity and cycle life in sodium ion batteries.

[0029] Example 2 Zinc salt and cyanamide salt were dissolved in water at a molar ratio of 1:6 and mixed. The cyanamide salt was a mixture of monocyanamide and dicyandiamide, with a 0.5 M aqueous solution concentration. The zinc salts were zinc chloride and zinc nitrate, with a 0.5 M aqueous solution concentration. Benzylamine and ethanolamine were used as precipitants. The molar ratio of the zinc salt to the precipitant hydroxide ions was 1:2, and the precipitant solution concentration was 0.5 M. The precipitant was added dropwise to the mixed solution at 50°C for 2 hours. The resulting zinc cyanamide was dispersed in an ethylene glycol solution at a concentration of 0.05 M. An ion exchange reaction was then carried out by adding a mixture of thiourea and thioacetamide dropwise to the zinc cyanamide solution. The sulfur-containing compound concentration was 0.08 M, and the volume ratio of the zinc cyanamide solution to the sulfur-containing compound solution was 0.5:1. The reaction temperature was 80°C, and the reaction time was 3 hours. Finally, a sodium ion negative electrode material with a zinc cyanamide / zinc sulfide heterostructure was obtained. The average diameter of the negative electrode particles was 500 nm, and the thickness of the ZnS shell was 5 nm. The capacity of the negative electrode material reached 690 mAh / g, the discharge capacity was 300 mAh / g at a current density of 10 A / g, and the capacity retention rate was 85% after 1000 cycles.

[0030] Example 3 Zinc salt and cyanamide salt were dissolved in water at a molar ratio of 1:6 and mixed and stirred. The cyanamide salt was a mixture of cyanuric acid and sodium bicarbonate, with an aqueous solution concentration of 0.2 M. The zinc salt was zinc nitrate and zinc acetate, with an aqueous solution concentration of 0.3 M. Triethanolamine and oleylamine were used as precipitants. The molar ratio of zinc salt to precipitant hydroxide ions was 1:4, and the precipitant solution concentration was 0.1 M. The precipitant was added dropwise to the mixed solution at 80°C for 3 hours. The resulting zinc cyanamide was dispersed in an ethanolamine solution at a concentration of 0.05 M. An ion exchange reaction was then carried out by adding a mixture of sodium sulfide and thioacetic acid dropwise to the zinc cyanamide solution at a sulfur-containing compound concentration of 0.04 M. The volume ratio of zinc cyanamide solution to sulfur-containing compound solution was 2:1. The reaction temperature was 100°C, and the reaction time was 1 hour. Finally, a sodium ion negative electrode material with a zinc cyanamide / zinc sulfide heterostructure was obtained. The average diameter of the negative electrode particles was 800 nm, and the thickness of the ZnS shell was 8 nm. The capacity of the negative electrode material reached 720 mAh / g, the discharge capacity was 350 mAh / g at a current density of 10 A / g, and the capacity retention rate was 88% after 1000 cycles.

[0031] Example 4 Zinc salt and cyanamide salt were dissolved in water at a molar ratio of 1:8 and mixed and stirred. The cyanamide salt was a mixture of cyanuric acid and sodium bicarbonate, with an aqueous solution concentration of 1 M. The zinc salt was zinc nitrate and zinc acetate, with an aqueous solution concentration of 0.8 M. Triethanolamine was used as the precipitant. The molar ratio of the zinc salt to the precipitant hydroxide ion was 1:7, and the precipitant solution concentration was 0.1 M. The precipitant was added dropwise to the mixed solution at 90°C for 10 hours. The resulting zinc cyanamide was dispersed in an ethanolamine solution to a concentration of 0.02 M. A mixture of sodium sulfide and thioacetic acid was then added dropwise to the zinc cyanamide solution. An ion exchange reaction was carried out via a solvothermal method. The concentration of the sulfur-containing compound was 0.2 M, the volume ratio of the zinc cyanamide solution to the sulfur-containing compound solution was 5:1, and the reaction temperature was 150°C for 5 hours. Finally, a sodium ion negative electrode material with a zinc cyanamide / zinc sulfide heterostructure was obtained. The average diameter of the negative electrode particles was 300 nm and the ZnS shell thickness was 4 nm. The capacity of the negative electrode material reached 890 mAh / g, the discharge capacity was 480 mAh / g at a current density of 10 A / g, and the capacity retention rate was 81% after 1000 cycles.

[0032] Example 5 Zinc salt and cyanamide salt were dissolved in water at a molar ratio of 1:40 and mixed and stirred. The cyanamide salt was sodium bicarbonate, with a 1M aqueous solution concentration; the zinc salts were zinc nitrate, zinc sulfate, and zinc acetate, with a 2M aqueous solution concentration. Ammonia was used as the precipitant. The molar ratio of zinc salt to precipitant hydroxide ions was 1:30, and the precipitant solution concentration was 0.2 M. The precipitant was added dropwise to the mixed solution at 30°C for 40 hours. The prepared zinc cyanamide was dispersed in an ethanolamine solution at a concentration of 0.1 M. L-cysteine ​​was then added dropwise to the zinc cyanamide solution. An ion exchange reaction was carried out using a sol-gel method. The concentration of the sulfur-containing compound was 0.4 M, and the volume ratio of the zinc cyanamide solution to the sulfur-containing compound solution was 0.2:1. The reaction temperature was 30°C, and the reaction time was 40 hours. Finally, a sodium ion negative electrode material with a zinc cyanamide / zinc sulfide heterostructure was obtained. The average diameter of the negative electrode particles was 300 nm, and the thickness of the ZnS shell was 2 nm. The capacity of the negative electrode material reached 850 mAh / g, the discharge capacity was 400 mAh / g at a current density of 10 A / g, and the capacity retention rate was 85% after 3000 cycles.

[0033] In summary, the present invention uses cyanamide salt and zinc salt as reaction raw materials, and utilizes a precipitation method combined with a low-temperature reaction to obtain a negative electrode material for a sodium ion battery having 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. Among them, the negative electrode material can provide a reversible specific capacity of 300~900 mAh / g, and achieve rate discharge at a high current density of 10 A / g and a cycle life of 300~3000 times. At the same time, the preparation method of the present invention abandons the use of hazardous chemical reagents, the experimental process can be carried out at normal pressure, the preparation process is simple, the cost is low, and it is suitable for promotion.

[0034] The foregoing descriptions of specific exemplary embodiments of the present invention are for purposes of illustration and description. These descriptions are not intended to limit the invention to the precise forms disclosed, and it is apparent that many variations and modifications are possible in light of the foregoing teachings. The exemplary embodiments have been selected and described for the purpose of explaining the specific principles of the invention and their practical application, thereby enabling those skilled in the art to realize and utilize a variety of exemplary embodiments of the invention and various options and modifications. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A negative electrode material for a sodium ion battery 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 of the particle can be controlled in the range of 50 to 1000 nm, and the thickness of the outer protective shell can be adjusted to 2 to 100 nm.

2. A method for preparing a negative electrode material for a sodium ion battery having a zinc cyanamide / zinc sulfide heterostructure according to claim 1, characterized in that: The following steps are involved: (1) dissolving a cyanamide salt and a zinc salt in water and mixing them uniformly, adding a precipitant solution, and performing a precipitation reaction at 20 to 120° C. for 0.5 to 48 hours to obtain zinc cyanamide; dispersing the zinc cyanamide in an organic solvent to prepare a zinc cyanamide solution with a concentration of 0.01 to 1 M; (2) Adding a sulfur-containing compound aqueous solution to the zinc cyanamide solution, and carrying out an ion exchange reaction at 30-180° C. for 0.5-48 h, wherein the concentration of the sulfur-containing compound aqueous solution is 0.02-1 M, and the volume ratio of the zinc cyanamide solution to the sulfur-containing compound aqueous solution is (0.2-10):1, thereby obtaining the sodium ion battery negative electrode material having a zinc cyanamide / zinc sulfide heterostructure.

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

4. The method for preparing a negative electrode material for a sodium ion battery having a zinc cyanamide / zinc sulfide heterostructure according to claim 2, 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.

5. The method for preparing a negative electrode material for a sodium ion battery having a zinc cyanamide / zinc sulfide heterostructure according to claim 2, characterized in that: The precipitant in the precipitant solution 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.

6. The method for preparing a negative electrode material for a sodium ion battery having a zinc cyanamide / zinc sulfide heterostructure according to claim 2, 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 of the precipitant solution is 1:(0.1-50).

7. The method for preparing a negative electrode material for a sodium ion battery having a zinc cyanamide / zinc sulfide heterostructure according to claim 2, characterized in that: The organic solvent is selected from one or more of ethylene glycol, ethanolamine, N-methylpyrrolidone, dimethylformamide and dimethyl sulfoxide.

8. The method for preparing a negative electrode material for a sodium ion battery having a zinc cyanamide / zinc sulfide heterostructure according to claim 2, characterized in that: The sulfur-containing compound is selected from one or more of thiourea, thioacetamide, sodium sulfide, thioacetic acid and L-cysteine.

9. A sodium ion battery, characterized in that: The sodium ion battery includes the negative electrode material for a sodium ion battery with a zinc cyanamide / zinc sulfide heterostructure according to claim 1 or the negative electrode material for a sodium ion battery with a zinc cyanamide / zinc sulfide heterostructure prepared by the preparation method according to any one of claims 2 to 8.

10. Use of the negative electrode material for a sodium ion battery having a zinc cyanamide / zinc sulfide heterostructure according to claim 1 or the negative electrode material for a sodium ion battery having a zinc cyanamide / zinc sulfide heterostructure prepared by the preparation method according to any one of claims 2 to 8 in the field of sodium ion batteries.

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