Molybdenum disulfide-carbon-tin disulfide hetero-material, preparation method and application

Abstract

This application relates to a molybdenum disulfide-carbon-tin disulfide heterostructure, its preparation method, and its application. The molybdenum disulfide-carbon-tin disulfide heterostructure has a nanoflower-like structure, comprising nanoflowers and nanospheres composited on the nanoflowers. The nanospheres are composed of MoS2 / C, and the nanoflowers are composed of SnS2. This composite material exhibits very high capacity and cycle stability, making it suitable for application as a negative electrode material in high-energy-density sodium-ion batteries.

Description

Technical Field

[0001] This application relates to the fields of nanomaterials and electrochemical energy storage, and in particular to a molybdenum disulfide-carbon-tin disulfide heteromaterial, its preparation method, and its application. Background Technology

[0002] The current severe ecological environment forces us to seek more valuable energy storage methods, with the aim of inventing a highly efficient energy conversion and storage device. Lithium-ion batteries are known for their large capacity and fast charging, but the scarcity and limited distribution of resources restrict their further development.

[0003] Sodium resources are widely distributed on Earth, and sodium-ion batteries share the same "rocking chair" charge-discharge principle as lithium-ion batteries. The larger radius of Na+ ions compared to Li+ ions makes insertion / de-insertion in the crystal lattice more difficult, leading to rapid capacity decay.

[0004] Therefore, a suitable electrode material is urgently needed to solve this problem. Transition metal sulfides have high electrochemical activity and thermodynamic stability, and the metal-sulfur bond is weaker than the metal-oxygen bond, thus attracting widespread attention as the anode material for sodium-ion batteries. Tin disulfide (SnS2) is a typical metal sulfide with high theoretical specific capacity, low cost, environmental friendliness, and abundant resources.

[0005] However, SnS2 is a common defect of sulfides, with inherently low conductivity and unavoidable volume expansion during charge and discharge, resulting in poor cycle performance and rate performance. Summary of the Invention

[0006] This application provides a molybdenum disulfide-carbon-tin disulfide heterostructure, its preparation method, and its application. This composite material has very high capacity and cycle stability, and is suitable for use as a negative electrode material in high-energy-density sodium-ion batteries.

[0007] In a first aspect, a molybdenum disulfide-carbon-tin disulfide heterostructure is provided, wherein the molybdenum disulfide-carbon-tin disulfide heterostructure has a nanoflower structure, and the nanoflower structure includes nanoflowers and nanospheres composited on the nanoflowers, wherein the composition of the nanospheres is MoS2 / C, and the composition of the nanoflowers is SnS2.

[0008] In some embodiments, the particle size of the nanoflower structure is 2 μm to 3 μm.

[0009] In some embodiments, the nanospheres have a particle size of 300–500 nm.

[0010] Secondly, a method for preparing a molybdenum disulfide-carbon-tin disulfide heteromaterial as described in any of the above-mentioned embodiments is provided, comprising the following steps:

[0011] A molybdenum source, hexadecyltrimethylammonium bromide (CTAB), and a sulfur source were added to a solvent, stirred to dissolve, and reacted under the first condition to obtain MoS2.

[0012] MoS2 was mixed with a carbon source, and after adjusting the pH, the mixture was stirred, centrifuged, and dried in sequence. Then, it was carbonized under an inert gas protection to obtain MoS2 / C.

[0013] MoS2 / C, tin source, hexadecyltrimethylammonium bromide (CTAB) and sulfur source were added to a solvent, stirred and dissolved, and reacted under a second condition to obtain a molybdenum disulfide-carbon-tin disulfide heteromaterial.

[0014] In some embodiments, the molybdenum source is at least one of ammonium molybdate and sodium molybdate;

[0015] And / or, the solvent is at least one of isopropanol, ethylene glycol and deionized water;

[0016] And / or, the sulfur source is at least one of thioacetamide and thiourea;

[0017] And / or, the first condition includes: reacting at 160°C to 200°C for 8 to 12 hours;

[0018] And / or, the carbon source is at least one of dopamine hydrochloride and polypyrrole;

[0019] And / or, after adjusting the pH, stir for 12 hours;

[0020] And / or, adjust the pH to 7.5–9;

[0021] And / or, during carbonization, the carbonization temperature is 580℃~620℃, and the carbonization time is 2h~4h;

[0022] And / or, the inert gas is argon or helium;

[0023] And / or, the tin source is tin tetrachloride;

[0024] And / or, the second condition includes: reacting at 160°C to 200°C for 8 to 12 hours.

[0025] In some embodiments, when the molybdenum source, hexadecyltrimethylammonium bromide (CTAB), and sulfur source are added to the solvent, the molar ratio of the molybdenum source to the sulfur source is 1:(1-2).

[0026] In some embodiments, the mass ratio of MoS2 to carbon source is 1:(1 to 1.5).

[0027] In some embodiments, when MoS2 / C, tin source, hexadecyltrimethylammonium bromide (CTAB), and sulfur source are added to the solvent, the molar ratio of MoS2 / C to tin source is 1:(2-3.5).

[0028] In some embodiments, when MoS2 / C, tin source, hexadecyltrimethylammonium bromide (CTAB), and sulfur source are added to the solvent, the molar ratio of MoS2 / C to sulfur source is 1:(4-6).

[0029] Thirdly, an application of the molybdenum disulfide-carbon-tin disulfide heteromaterial as described above in sodium-ion batteries is provided.

[0030] The beneficial effects of the technical solution provided in this application include:

[0031] This application provides a molybdenum disulfide-carbon-tin disulfide heterostructure, its preparation method, and its application. The heterobimetallic sulfide MoS2 / C / SnS2 provided in this application can improve conductivity by establishing an internal electric field, while the heterostructure interface can provide abundant sodium ion sites, thereby improving sodium ion storage and shortening the sodium ion migration path, thus accelerating ion / electron migration. Therefore, this composite material exhibits very high capacity and cycle stability, making it suitable for application as a negative electrode material in high-energy-density sodium-ion batteries.

[0032] Furthermore, the presence of nanoflowers means that the nanoflower ball structure is not a solid structure, as there are spaces between the petals, making it similar to a hollow structure. This helps to alleviate volume expansion during charging and discharging. The C coating improves the stability of the material structure and reduces the expansion rate, thereby further improving the capacity and cycle stability.

[0033] As a negative electrode in sodium-ion batteries, MoS2 / C / SnS2 at 2A·g -1 The current density can reach 660 mAh·g -1 The reversible capacity is 10 A·g -1 Even under high current density, it can maintain 603mAh·g after 2500 cycles. -1 The capacity of MoS2 / C / SnS2 is significantly higher than that of MoS2 and SnS2 in terms of electrochemical performance. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 The SEM images provided for this application are as follows: a is the SEM image of MoS2 / C / SnS2 in Example 1; b is the SEM image of SnS2 in Example 3; and c is the SEM image of MoS2 / C in Example 2.

[0036] Figure 2 XRD patterns of Embodiments 1, 2, and 3 provided for this application;

[0037] Figure 3 Examples 1, 2, and 3 provided for this application are in 2A·g -1 Cyclic plot at current density;

[0038] Figure 4 Example 1 provided for this application is in 10A·g -1 Cyclic plot at current density. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0040] This application provides a molybdenum disulfide-carbon-tin disulfide heterostructure, wherein the molybdenum disulfide-carbon-tin disulfide (MoS2 / C / SnS2) heterostructure has a nanoflower structure, and the nanoflower structure includes nanoflowers and nanospheres composited on the nanoflowers (see...). Figure 1 As shown in the figure, the nanospheres are composed of MoS2 / C, and the nanoflowers are composed of SnS2.

[0041] The heterobimetallic sulfide MoS2 / C / SnS2 provided in this application, where C coats the outer surface of MoS2 to form a spherical structure, which is then composited onto tin disulfide, can improve conductivity by establishing an internal electric field. The heterojunction interface provides abundant sodium ion sites, thereby improving sodium ion storage and shortening the sodium ion migration path, thus accelerating ion / electron migration. Therefore, this composite material exhibits very high capacity and cycle stability, making it suitable for application as a negative electrode material in high-energy-density sodium-ion batteries.

[0042] Furthermore, the presence of nanoflowers means that the nanoflower ball structure is not a solid structure, as there are spaces between the petals, making it similar to a hollow structure. This helps to alleviate volume expansion during charging and discharging. The C coating improves the stability of the material structure and reduces the expansion rate, thereby further improving the capacity and cycle stability.

[0043] The nanoflower structure has a particle size of 2μm to 3μm, and the nanospheres have a particle size of 300 to 500nm.

[0044] This application also provides a method for preparing any of the above-described molybdenum disulfide-carbon-tin disulfide heteromaterials, comprising the following steps:

[0045] 101: Molybdenum source, hexadecyltrimethylammonium bromide (CTAB) and sulfur source are added to a solvent, stirred to dissolve, and reacted under the first condition to obtain MoS2.

[0046] Specifically, step 101 includes: dissolving the molybdenum source in 50 ml of solvent, adding an appropriate amount of hexadecyltrimethylammonium bromide (CTAB), stirring, and sonicating for one hour to ensure dissolution. Then, adding an appropriate sulfur source, pouring the mixed solution into a Teflon liner, and reacting at 160°C–200°C for 8–12 hours. The black powder is collected by centrifugation, washed with deionized water and alcohol, and dried overnight in a vacuum oven to finally obtain the first-step product, MoS2.

[0047] When molybdenum source, hexadecyltrimethylammonium bromide (CTAB), and sulfur source are added to the solvent, the molar ratio of molybdenum source to sulfur source is 1:(1-2).

[0048] There are various types of molybdenum sources to choose from. For example, as an example, the molybdenum source can be at least one of ammonium molybdate and sodium molybdate.

[0049] There are various types of solvents that can be selected. For example, the solvent can be at least one of isopropanol, ethylene glycol, and deionized water.

[0050] There are various types of sulfur sources to choose from. For example, the sulfur source can be at least one of thioacetamide and thiourea.

[0051] 102: Mix MoS2 with a carbon source at a mass ratio of 1:(1~1.5), adjust the pH, and then stir, centrifuge, and dry the mixture. Finally, carbonize the mixture under an inert gas atmosphere to obtain MoS2 / C.

[0052] Specifically, step 102 includes: mixing an appropriate amount of MoS2 with a carbon source, adjusting the pH to 7.5–9, and stirring for 12 hours. After centrifugation and drying, the black powder is carbonized in a tube furnace under inert gas protection to obtain MoS2 / C.

[0053] The carbon source can be selected from a variety of types. For example, the carbon source can be at least one of dopamine hydrochloride and polypyrrole.

[0054] During carbonization, the carbonization temperature is 580℃~620℃ and the carbonization time is 2h~4h.

[0055] There are various types of inert gas to choose from; for example, argon or helium can be used.

[0056] 103: MoS2 / C, tin source, hexadecyltrimethylammonium bromide (CTAB) and sulfur source are added to a solvent, stirred and dissolved, and reacted under the second condition to obtain a molybdenum disulfide-carbon-tin disulfide heteromaterial.

[0057] Specifically, step 103 includes: dissolving MoS2 / C and a tin source in 50 ml of solvent, adding an appropriate amount of hexadecyltrimethylammonium bromide (CTAB) and a sulfur source, stirring and sonicating for one hour to ensure dissolution, pouring the mixed solution into a Teflon liner, and reacting at 160℃~200℃ for 8h~12h. The black powder is collected by centrifugation, washed with deionized water and alcohol, and dried overnight in a vacuum oven to finally obtain MoS2 / C / SnS2.

[0058] When MoS2 / C, tin source, hexadecyltrimethylammonium bromide (CTAB) and sulfur source are added to the solvent, the molar ratio of MoS2 / C to tin source is 1:(2-3.5), and the molar ratio of MoS2 / C to sulfur source is 1:(4-6).

[0059] There are various types of solvents that can be selected. For example, the solvent can be at least one of isopropanol, ethylene glycol, and deionized water.

[0060] There are various types of sulfur sources to choose from. For example, the sulfur source can be at least one of thioacetamide and thiourea.

[0061] There are various types of tin sources to choose from. For example, tin tetrachloride can be used as a tin source.

[0062] The preparation method provided in this application, through a simple solvothermal method and a subsequent annealing process (i.e., a process of cooling back to room temperature after high-temperature carbonization), yields heterogeneous nanospheres of MoS2 / C / SnS2 with synergistic effects. This method has advantages such as simple preparation process, low cost, and environmental friendliness and non-toxicity, and exhibits excellent cycle stability and capacity in sodium-ion batteries. The heterogeneous bimetallic sulfide strategy can improve conductivity by establishing an internal electric field. The heterogeneous interface provides abundant sodium ion sites, improving the sodium ion storage mode. At the same time, it shortens the sodium ion migration path and accelerates ion / electron migration dynamics. The hollow structure helps to alleviate volume expansion during charge and discharge, and the C coating improves the stability of the material structure and reduces the expansion rate, thereby further improving capacity and cycle stability.

[0063] Example 1

[0064] Step 1: Dissolve ammonium molybdate in 50 ml of isopropanol, add an appropriate amount of CTAB, stir and sonicate for one hour to ensure dissolution. Then add an appropriate amount of thioacetamide as a sulfur source, pour the mixed solution into a Teflon liner, and maintain at 180 degrees for 12 hours. Collect the black powder by centrifugation, wash with deionized water and alcohol, and dry in a vacuum oven overnight to finally obtain the first product, MoS2.

[0065] Step 2: Mix an appropriate amount of MoS2 with dopamine hydrochloride, adjust the pH, and stir for 12 hours. After centrifugation and drying, the black powder is heated at 600 degrees Celsius for 3 hours in an argon-protected tube furnace to obtain MoS2 / C.

[0066] Step 3: Dissolve the MoS2 / C obtained in Step 2 and tin tetrachloride in 50 ml of isopropanol, add appropriate amounts of CTAB and thioacetamide, stir and sonicate for one hour to ensure dissolution. Pour the mixed solution into a Teflon liner and maintain at 180 degrees Celsius for 12 hours. Collect the black powder by centrifugation, wash with deionized water and alcohol, and dry in a vacuum oven overnight to finally obtain nano-spherical MoS2 / C / SnS2. See [link to relevant documentation]. Figure 1 In the image 'a', it is clear that the petals of the SnS2 nanoflower are composited with many MoS2 / C nanospheres. (See also...) Figure 2 As shown, judging from the peak positions, MoS2 / C / SnS2 was successfully synthesized.

[0067] In step one, the mass of ammonium molybdate is 0.6g.

[0068] In step one, the molar ratio of ammonium molybdate to thioacetamide is 2:3.

[0069] In step two, the mass ratio of MoS2 to dopamine hydrochloride is 1:1.

[0070] In step three, the molar ratio of MoS2 / C to tin tetrachloride is 1:3.

[0071] In step three, the molar ratio of MoS2 / C to thioacetamide is 1:6.

[0072] Example 2

[0073] The difference between Example 2 and Example 1 is that Example 2 only performs steps one and two, omitting step three, ultimately obtaining MoS2 / C nanospheres. (See [link to example 1]). Figure 1 See c in the original text. Figure 2 As shown, judging from the peak positions, MoS2 / C was successfully synthesized.

[0074] Example 3

[0075] The difference between Example 3 and Example 1 is that Example 3 is based on step three of the preparation in Example 1, but without adding MoS2 / C, while keeping everything else unchanged, ultimately yielding nanoflower SnS2. See [link to example]. Figure 1 See b in the example. Figure 2 As shown, judging from the peak position, SnS2 was successfully synthesized.

[0076] Application Example 1

[0077] The nano-flower-shaped MoS2 / C / SnS2 heteromaterial prepared in Example 1 was used as the negative electrode of a sodium-ion battery. A blue electric battery testing system was used at 2 A·g -1 and 10A·g -1 Its electrochemical performance was tested using constant current charge-discharge technology at the current density, and the test results are as follows: Figure 3 and Figure 4 As shown, 2A·g -1 Maintaining 660 mAh·g after 500 cycles at current density -1 10A·g -1 Maintaining 603 mAh·g after 2500 cycles at current density -1 .

[0078] Application Example 2

[0079] The MoS2 / C material prepared in Example 2 was used as the negative electrode of a sodium-ion battery, and the blue electric battery testing system was used at 2 A·g -1 Its electrochemical performance was tested using constant current charge-discharge technology at the current density, and the test results are as follows: Figure 3 As shown, 2A·g -1 Maintains 396 mAh·g after 500 cycles at current density -1 .

[0080] Application Example 3

[0081] The SnS2 material prepared in Example 3 was used as the negative electrode of a sodium-ion battery, and the blue electric battery testing system was used at 2 A·g -1 Its electrochemical performance was tested using constant current charge-discharge technology at the current density, and the test results are as follows: Figure 3 As shown, 2A·g -1 Maintaining 380 mAh·g after 200 cycles at current density -1 .

[0082] It can be seen that, as a negative electrode in sodium-ion batteries, MoS2 / C / SnS2 exhibits performance at 2 A·g -1 The current density can reach 660 mAh·g -1 The reversible capacity is 10 A·g -1 Even under high current density, it can maintain 603mAh·g after 2500 cycles. -1 The capacity of MoS2 / C / SnS2 is significantly higher than that of MoS2 and SnS2 in terms of electrochemical performance.

[0083] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0084] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0085] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for preparing a molybdenum disulfide-carbon-tin disulfide heteromaterial, characterized in that: The molybdenum disulfide-carbon-tin disulfide heterostructure is a nanoflower-sphere structure, and the nanoflower-sphere structure includes nanoflowers and nanospheres composited on the nanoflowers, wherein the nanospheres are composed of MoS2 / C and the nanoflowers are composed of SnS2. The preparation method includes the following steps: A molybdenum source, hexadecyltrimethylammonium bromide (CTAB), and a sulfur source were added to a solvent, stirred to dissolve, and reacted under the first condition to obtain MoS2. MoS2 was mixed with a carbon source, and after adjusting the pH, the mixture was stirred, centrifuged, and dried in sequence. Then, it was carbonized under an inert gas protection to obtain MoS2 / C. MoS2 / C, tin source, hexadecyltrimethylammonium bromide (CTAB) and sulfur source were added to a solvent, stirred and dissolved, and reacted under a second condition to obtain a molybdenum disulfide-carbon-tin disulfide heteromaterial.

2. The method for preparing the molybdenum disulfide-carbon-tin disulfide heteromaterial as described in claim 1, characterized in that: The particle size of the nanoflower-shaped structure is 2μm~3μm.

3. The method for preparing the molybdenum disulfide-carbon-tin disulfide heteromaterial as described in claim 1, characterized in that: The nanospheres have a particle size of 300~500 nm.

4. The method for preparing the molybdenum disulfide-carbon-tin disulfide heteromaterial as described in claim 1, characterized in that: The molybdenum source is at least one of ammonium molybdate and sodium molybdate; And / or, the solvent is at least one of isopropanol, ethylene glycol and deionized water; And / or, the sulfur source is at least one of thioacetamide and thiourea; And / or, the first condition includes: reacting at 160°C to 200°C for 8 to 12 hours; And / or, the carbon source is at least one of dopamine hydrochloride and polypyrrole; And / or, after adjusting the pH, stir for 12 h; And / or, adjust the pH to 7.5-9; And / or, during carbonization, the carbonization temperature is 580℃~620℃, and the carbonization time is 2h~4h; And / or, the inert gas is argon or helium; And / or, the tin source is tin tetrachloride; And / or, the second condition includes: reacting at 160°C to 200°C for 8 to 12 hours.

5. The method for preparing the molybdenum disulfide-carbon-tin disulfide heteromaterial as described in claim 1, characterized in that: When molybdenum source, hexadecyltrimethylammonium bromide (CTAB), and sulfur source are added to the solvent, the molar ratio of molybdenum source to sulfur source is 1:(1~2).

6. The method for preparing the molybdenum disulfide-carbon-tin disulfide heteromaterial as described in claim 1, characterized in that: The mass ratio of MoS2 to carbon source is 1:(1~1.5).

7. The method for preparing the molybdenum disulfide-carbon-tin disulfide heteromaterial as described in claim 1, characterized in that: When MoS2 / C, tin source, hexadecyltrimethylammonium bromide (CTAB), and sulfur source are added to the solvent, the molar ratio of MoS2 / C to tin source is 1:(2~3.5).

8. The method for preparing the molybdenum disulfide-carbon-tin disulfide heteromaterial as described in claim 1, characterized in that: When MoS2 / C, tin source, hexadecyltrimethylammonium bromide (CTAB), and sulfur source are added to the solvent, the molar ratio of MoS2 / C to sulfur source is 1:(4~6).

9. The application of a molybdenum disulfide-carbon-tin disulfide heteromaterial prepared by the preparation method of molybdenum disulfide-carbon-tin disulfide heteromaterial as described in any one of claims 1 to 8 in a sodium-ion battery.

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