Cu2-xS (at) MoS2 nano heterojunction, preparation method thereof and application of Cu2-xS (at) MoS2 nano heterojunction in secondary battery

Abstract

The invention relates to a Cu2-xS-MoS2 nano heterojunction, a preparation method thereof and application of the Cu2-xS-MoS2 nano heterojunction in a secondary battery, and the preparation method comprises the following steps: carrying out heating reaction on a sulfur-containing copper source and a molybdenum source in an organic solvent to obtain the Cu2-xS-MoS2 nano heterojunction, or heating and reacting the copper source, the molybdenum source and the sulfur source in an organic solvent. Compared with the prior art, the method has the advantages of simple and controllable process flow, low cost, high repeatability, environmental friendliness and the like; meanwhile, the Cu2-xS-MoS2 nano heterojunction synthesized by the method has the characteristics of regular hexagonal morphology, excellent structural stability and high ion and electron conductivity, and has a wide application prospect in secondary ion batteries in the future.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of metal sulfides, and relates to a Cu 2–x S@MoS2 nano-heterojunction and a preparation method and application thereof in secondary batteries. BACKGROUND

[0002] In the technical field of rechargeable magnesium battery positive electrode materials, metal sulfide nano-heterojunctions are a new type of nanomaterials, which have the advantages of excellent structural stability, high ionic conductivity and high electronic conductivity in addition to the characteristics of ordinary metal sulfides such as large capacity and good cycle stability. The above characteristics can effectively inhibit the structural change of conversion-type positive electrode materials during the cycle process, thereby improving the overall performance of the battery, and are expected to become magnesium ion battery positive electrode materials with high reversible capacity and long cycle life. Specifically, when Cu 2–x S and MoS2 are in close contact, band alignment occurs spontaneously at the heterojunction interface and a built-in electric field is formed, which can significantly improve the conductivity of the material. The currently reported metal sulfide nano-heterojunctions are mainly applied in the fields of electrocatalysis and battery negative electrode materials, and the related research on using them as rechargeable magnesium battery positive electrode materials is still in the exploratory stage. Cu 2–x S and MoS2 belong to triclinic and hexagonal systems respectively, and there is a problem of lattice mismatch between them; at the same time, due to the large difference in bond energy between Mo and Cu and S, it is difficult to controllably grow MoS2 on the surface of Cu 2–x S. Therefore, it is of unique scientific and technological value to develop a preparation method of Cu 2–x S@MoS2 nano-heterojunction to obtain a high-performance metal sulfide magnesium storage positive electrode material. The material has broad application prospects in the fields of lithium ion batteries, sodium ion batteries, and magnesium ion batteries, and other secondary batteries. SUMMARY

[0003] The purpose of the present application is to provide a Cu 2–x S@MoS2 nano-heterojunction and a preparation method and application thereof in secondary batteries. The present application has the advantages of simple and controllable process flow, low cost, high repeatability, and environmental friendliness; at the same time, the Cu 2–x S@MoS2 nano-heterojunction synthesized by the present application has the characteristics of regular hexagonal morphology, excellent structural stability, and high ionic and electronic conductivity, and has broad application prospects in future secondary ion batteries.

[0004] The purpose of the present application can be achieved by the following technical solutions: The first aspect of the present application provides a Cu 2–xThe application discloses a preparation method of S@MoS2 nano-heterojunction.

[0005] In some specific embodiments, the sulfur-containing copper source is CuSCN; the molybdenum source is selected from one of MoCl5, (NH4)6Mo7O 24 or Na2MoO4; The molar ratio of the sulfur-containing copper source and the molybdenum source is 1:0.5-1.

[0006] In some specific embodiments, in the heating reaction, the reaction temperature is 240-260 DEG C, the reaction time is 0.5-1 h, and the reaction environment is a nitrogen atmosphere, an inert gas atmosphere or a vacuum environment; the organic solvent is at least one selected from oleylamine, 1-octadecene or oleic acid, and the feeding ratio of the sulfur-containing copper source is (15-30) mL:1 mmol. Preferably, the organic solvent is selected from oleylamine, a mixed solvent of oleylamine and 1-octadecene with a volume ratio of 3:1, or a mixed solvent of oleylamine and oleic acid with a volume ratio of 5:1.

[0007] The second aspect of the application provides a Cu 2–x The application discloses a preparation method of S@MoS2 nano-heterojunction.

[0008] In some specific embodiments, the sulfur-containing copper source is selected from one of a halide, Cu(acac)2 or Cu(NO3)2; the molybdenum source is selected from one of MoCl5, (NH4)6Mo7O 24 or Na2MoO4; the sulfur source is dodecyl mercaptan; and the feeding ratio of the copper source, the molybdenum source and the sulfur source is 1 mmol:0.5-1 mmol:5-10 mL. Preferably, the halide is selected from CuI2 or CuCl2.

[0009] In some specific embodiments, in the heating reaction, the reaction temperature is 240-260 DEG C, the reaction time is 0.5-1 h, and the reaction environment is a nitrogen atmosphere, an inert gas atmosphere or a vacuum environment; the organic solvent is at least one selected from oleylamine, 1-octadecene or oleic acid, and the feeding ratio of the sulfur-containing copper source is (15-30) mL:1 mmol. Preferably, the organic solvent is selected from oleylamine, a mixed solvent of oleylamine and 1-octadecene with a volume ratio of 3:1, or a mixed solvent of oleylamine and oleic acid with a volume ratio of 5:1.

[0010] In some specific embodiments, before the heating reaction, low-temperature heating is further included to remove water, oxygen and other low-boiling-point impurities; preferably, in the low-temperature heating, the heating temperature is 100-120 DEG C, the heating time is 0.5-1 h, and the heating atmosphere is vacuum, nitrogen or inert gas.

[0011] A third aspect of the present invention provides a Cu 2–x The S@MoS2 nanoheterojunction was prepared using the method described above.

[0012] In some specific embodiments, the Cu 2–x The S@MoS2 nanoheterostructure has a particle size of 15 nm to 30 nm. The outer layer of the nanosheet is a monolayer of MoS2 molecules, with S atoms uniformly distributed on both sides of the Mo atoms. The inner layer of S atoms is connected to Cu atoms. 2-x The outer Cu atoms of S are bonded, and the bottom and sides of the nanosheet are covered with MoS2. The ratio of Cu to Mo is 9:1.

[0013] The fourth aspect of the present invention provides a Cu as described above. 2–x Applications of S@MoS2 nanoheterojunctions include the Cu 2–x S@MoS2 nanoheterojunctions are used as cathode materials in the fabrication of lithium-ion, sodium-ion, or magnesium-ion batteries.

[0014] In some specific embodiments, the method for preparing the magnesium-ion battery includes: An ethylene glycol dimethyl ether solution of Mg(TFSI)2 and MgCl2 was used as the electrolyte; With Cu 2-x The positive electrode is obtained by mixing, grinding, slurry preparation, pressing, and drying S@MoS2 nano-heterojunction as the positive electrode active material, Ketjen black as the conductive agent, and polytetrafluoroethylene (PTFE) as the binder. It was prepared using Mg sheet as the negative electrode; Preferably, the molar concentration of Mg(TFSI)₂ is 0.5~1 M, and the molar concentration of MgCl₂ is 1~1.5 M; the Cu 2-x The mass ratio of S@MoS2 nanoheterojunction, Ketjen black, and polytetrafluoroethylene is 6:2~3:2~3.

[0015] This invention uses a colloidal chemical method to prepare Cu 2–x In the S@MoS2 nanoheterostructure method, under the action of ligands, the metal salt can gradually and slowly release Cu and S, achieving a local concentration balance of Cu, Mo, and S. This overcomes the problem that the large bond energy difference between Mo and Cu and S prevents MoS2 from being absorbed by Cu. 2–x The problem of achieving controllable epitaxial growth on S surfaces. Due to Cu 2–x The a-axis lattice parameter of S differs significantly from that of MoS2, while its b-axis lattice parameter is closer to that of MoS2. Therefore, Mo diffusion in the sublattice tends to occur along the a-axis. The lattice differences along other axes are too large, preventing Mo from further diffusing into Cu.2–x S diffuses inside, thus finally forming a two-dimensional layered structure on the Cu 2–x S diffuses outside, thus finally forming a two-dimensional layered structure on the Cu

[0016] Compared with the prior art, the present application has the following beneficial effects: 1) The present application prepares a Cu 2–x S@MoS2 nanoheterojunction material, which can be widely applied in the field of secondary batteries such as lithium ion batteries, sodium ion batteries, and magnesium ion batteries; 2) The present application develops a universal MoS2-coated Cu 2–x S method, which can precisely realize sub-monolayer MoS2 coating on the surface of Cu 2–x S nanosheets; 3) The Cu 2–x S@MoS2 nanoheterojunction prepared by the present application has good structural stability and structural reversibility, and the magnesium battery assembled by using the Cu BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 X-ray diffraction pattern of the Cu 2–x S@MoS2 nanoheterojunction prepared in Example 1; Figure 2 Transmission electron microscope image of the Cu 2–x S@MoS2 nanoheterojunction prepared in Example 1; Figure 3 High-resolution transmission electron microscope image of the Cu 2–x S@MoS2 nanoheterojunction prepared in Example 1; Figure 4 Element distribution map of the Cu 2–x S@MoS2 nanoheterojunction prepared in Example 1; Figure 5 Metal element content map of the Cu 2–x S@MoS2 nanoheterojunction prepared in Example 1; Figure 6 Charge-discharge curve of the Cu 2–x S@MoS2 nanoheterojunction magnesium battery prepared in Example 1; Figure 7 Cycle performance map of the Cu 2–x S@MoS2 nanoheterojunction magnesium battery prepared in Example 1; Figure 8 Rate performance map of the Cu 2–x S@MoS2 nanoheterojunction magnesium battery prepared in Example 1; Figure 9 Cu 2–xS@MoS2 nano-heterojunction magnesium battery charge-discharge curves; Figure 10 Cu prepared for Comparative Example 1 2–x Cycling performance diagram of S@MoS2 nano-heterojunction magnesium battery; Figure 11 Cu prepared for Comparative Example 1 2–x Rate performance diagram of S@MoS2 nano-heterojunction magnesium solar cell. Detailed Implementation

[0018] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0019] In view of the shortcomings of existing technologies, the inventors, through long-term research and extensive practice, have proposed the technical solution of this invention. This invention is based on a liquid-phase synthesis strategy, using a metal salt as the metal source, thiocyanate ions as the sulfur source, and oleylamine as the solvent, employing in-situ sulfidation technology. Cuprous ions preferentially react with sulfide anions to generate Cu. 2–x S nanoparticles; molybdenum ions and sulfide anions in Cu 2–x A directional reaction occurs on the S surface to form a monolayer of MoS2. The inner sulfur atoms of MoS2 react with Cu atoms. 2–x The outer copper atoms of S form chemical bonds, while MoS2 covers Cu. 2–x By examining the bottom and side surfaces of S, a Cu with a "shell-core" structure is obtained. 2–x S@MoS2 nanoheterojunctions are expected to be widely used in the field of secondary batteries such as lithium / sodium / magnesium batteries.

[0020] One aspect of the present invention provides a Cu 2–x S@MoS2 nanoheterojunctions are used in rechargeable magnesium batteries. The Cu... 2–x The S@MoS2 nanoheterostructure has a particle size of 15 nm to 30 nm. The outer layer of the nanosheet is a monolayer of MoS2 molecules, with S atoms uniformly distributed on both sides of the Mo atoms. The inner layer of S atoms is connected to Cu atoms. 2–x The outer Cu atoms of S are bonded, and the bottom and sides of the nanosheet are covered with MoS2. The ratio of Cu to Mo is approximately 9:1. The Cu... 2–x The S@MoS2 nanoheterojunction did not exhibit lattice mismatch or structural collapse due to the significant differences in bond energies between Mo, Cu, and S atoms.

[0021] Another aspect of the present invention also provides the aforementioned Cu 2–x The preparation method of S@MoS2 nanoheterostructures includes: The metal salt and oleylamine were mixed uniformly and stirred at room temperature to form the homogeneous mixed solution reaction system described above. The heating reaction is carried out under inert gas protection using the homogeneous mixed solution system, and a homogeneous mixed solution with impurities removed is obtained; Further, the heating reaction is continuously carried out under inert gas protection using the homogeneous mixed solution system, and the Cu 2–x S@MoS2nanoheterojunction.

[0022] In some more specific embodiments, the preparation method comprises: (1) mixing a copper salt, a molybdenum salt, a sulfur source and a solvent uniformly, and removing water, oxygen and low-boiling-point impurities under vacuum, nitrogen or inert gas atmosphere and at 100-120 ℃ for 0.5-1 h to obtain a homogeneous mixed solution; (3) reacting the homogeneous mixed solution with impurities removed under nitrogen or inert gas atmosphere and at 240-260 ℃ for 0.5-1 h to obtain the target product Cu 2–x S@MoS2nanoheterojunction.

[0023] Further, the copper salt is selected from at least one of thiocyanate, nitrate, halide or acetylacetone salt, and is not limited thereto; the molybdenum salt is selected from at least one of chloride or molybdate, and is not limited thereto; the sulfur source is selected from one of cuprous thiocyanate and dodecyl mercaptan, and is not limited thereto; the solvent is selected from at least one of oleylamine, oleic acid and 1-octadecene, and is not limited thereto. Preferably, cuprous thiocyanate, molybdenum chloride and oleylamine are used.

[0024] Further, the feeding ratio of the copper salt, the molybdenum salt, the sulfur source and the solvent is 1 mmol: (0.5-1) mmol: (0-5) mL: (15-30) mL. Preferably, the feeding ratio of cuprous cyanide, molybdenum chloride and oleylamine is 1 mmol: 1 mmol: 15 mL.

[0025] The embodiment of the present application also provides the aforementioned Cu 2–x The Cu

[0026] The embodiment is implemented on the premise of the technical solution of the present application, and gives a detailed implementation manner and specific operation process, but the protection scope of the present application is not limited to the following embodiments.

[0027] The following is a more detailed implementation case, which further illustrates the technical solution of the present application and the technical effects that can be obtained.

[0028] In the following embodiments, if there is no special description of raw materials or processing technology, it means that they are all conventional commercially available products or conventional processing technology in the art.

[0029] Example 1 The embodiment provides a Cu 2-x The S@MoS2 nano-heterojunction is prepared by the method, and the method comprises the following steps: 1 mmol of CuSCN and 1 mmol of MoCl5 are dissolved in 15 mL of oleylamine, vacuum pumping is performed, heating is performed to 100 DEG C, and reaction is performed for 0.5 h, then heating is continuously performed to 240 DEG C, and reaction is performed for 0.5 h. The product is washed three times by adding n-hexane / ethanol in a volume ratio of 1:1, and drying is performed in a vacuum oven at 80 DEG C for 24 h, so that the Cu 2-x S@MoS2 nano-heterojunction is obtained.

[0030] Assembly of the magnesium battery: 0.5 M Mg(TFSI)2 and 1 M MgCl2 dissolved in ethylene glycol dimethyl ether are selected as electrolyte; the Cu 2-x S@MoS2 nano-heterojunction is used as a positive active material, Ketjen black is used as a conductive agent, and PTFE is used as a binder, and the mass ratio among them is 6:2:2, the mixture is fully ground for 30 min, a slurry is prepared and rolled into a sheet, drying is performed in a vacuum oven at 80 DEG C for 12 h, and the sheet is cut into a round sheet with a diameter of 10 mm as a positive electrode. A metal Mg sheet with a diameter of 14 mm is used as a negative electrode, and the magnesium battery is assembled by using the above materials.

[0031] Example 2 The embodiment provides a Cu 2-x The S@MoS2 nano-heterojunction is prepared by the method, and the method comprises the following steps: The specific process is as follows: 1 mmol of CuSCN and 0.5 mmol of (NH4)6Mo7O 24 ·4H2O are dissolved in 15 mL of oleylamine, nitrogen is introduced, heating is performed to 100 DEG C, and reaction is performed for 0.5 h, then heating is continuously performed to 240 DEG C, and reaction is performed for 0.5 h.

[0032] The rest is the same as in example 1.

[0033] The Cu 2-x S@MoS2 nano-heterojunction is obtained.

[0034] Example 3 The embodiment provides a Cu 2-x The S@MoS2 nano-heterojunction is prepared by the method, and the method comprises the following steps: The specific process is as follows: 1 mmol CuI, 1 mmol Na2MoO4·2H2O and 5 mL dodecyl mercaptan were dissolved in 15 mL oleylamine, vacuumized, heated to 100 °C and reacted for 0.5 h, then continued to be heated to 240 °C and reacted for 0.5 h.

[0035] The rest is the same as example 1.

[0036] Finally, Cu 2-x S@MoS2nanoheterojunction.

[0037] Example 4 This example provides a Cu 2-x S@MoS2nanoheterojunction, the difference between the preparation method and example 1 is that different copper salt, molybdenum salt and sulfur source are selected; The specific process is as follows: 1 mmol Cu(acac)2, 1 mmol Na2MoO4·2H2O and 5 mL dodecyl mercaptan were dissolved in 15 mL oleylamine, vacuumized, heated to 100 °C and reacted for 0.5 h, then continued to be heated to 240 °C and reacted for 0.5 h.

[0038] The rest is the same as example 1.

[0039] Finally, Cu 2-x S@MoS2nanoheterojunction.

[0040] Example 5 This example provides a Cu 2-x S@MoS2nanoheterojunction, the difference between the preparation method and example 1 is that different copper salt, molybdenum salt and sulfur source are selected; The specific process is as follows: 1 mmol CuCl2, 1 mmol Na2MoO4·2H2O and 5 mL dodecyl mercaptan were dissolved in 15 mL oleylamine and 5 mL 1-octadecene, vacuumized, heated to 100 °C and reacted for 0.5 h, then continued to be heated to 260 °C and reacted for 1 h.

[0041] The rest is the same as example 1.

[0042] Finally, Cu 2-x S@MoS2nanoheterojunction.

[0043] Example 6 This example provides a Cu 2-x S@MoS2nanoheterojunction, the difference between the preparation method and example 1 is that different metal salt feeding ratio and reaction temperature are selected; The specific process is as follows: Dissolve 1 mmol CuSCN and 0.5 mmol MoCl5 in 15 mL oleylamine, pass nitrogen, heat to 120 ℃ and react for 1 h, then continue to heat to 260 ℃ and react for 0.5 h.

[0044] The rest is the same as Example 1.

[0045] Finally, Cu 2-x S@MoS2 nanoheterojunction is obtained.

[0046] Example 7 This example provides a Cu 2–x S@MoS2 nanoheterojunction, the difference between the preparation method and Example 1 is that different molybdenum salt and solvent are selected; The specific process is as follows: Dissolve 1 mmol CuSCN and 0.5 mmol (NH4)6Mo7O 24 ·4H2O in 15 mL oleylamine and 3 mL oleic acid, pass nitrogen, heat to 100 ℃ and react for 0.5 h, then continue to heat to 240 ℃ and react for 0.5 h.

[0047] The rest is the same as Example 1.

[0048] Finally, Cu 2-x S@MoS2 nanoheterojunction is obtained.

[0049] Example 8 This example provides a Cu 2-x S@MoS2 nanoheterojunction, the difference between the preparation method and Example 1 is that different molybdenum salt and solvent are selected; The specific process is as follows: Dissolve 1 mmol Cu(NO3)2·2.5H2O and 1 mmol MoCl5 and 5 mL dodecyl mercaptan in 15 mL oleylamine, vacuumize, heat to 100 ℃ and react for 0.5 h, then continue to heat to 240 ℃ and react for 0.5 h.

[0050] The rest is the same as Example 1.

[0051] Finally, Cu 2-x S@MoS2 nanoheterojunction is obtained.

[0052] Comparative Example 1 This example provides a Cu 2-x S nanosheet, the difference between the preparation method and Example 1 is only that: No molybdenum salt is added; The specific process is as follows: CuS nanosheets were prepared by dissolving 1 mmol CuSCN in 15 mL oleylamine, vacuumizing and heating to 100 ℃ for 0.5 h, and then continuously heating to 240 ℃ for 0.5 h. The product was washed with n-hexane / ethanol (1:1 by volume) three times and dried in a vacuum oven at 80 ℃ for 24 h. 2-x S nanosheets.

[0053] Assembly of magnesium battery: 0.5 M Mg(TFSI)2and 1 M MgCl2in ethylene glycol dimethyl ether were selected as electrolyte; Cu 2-x S nanosheets were used as positive active material, Ketjen black as conductive agent, and PTFE as binder, and the mass ratio among them was 6:2:2. The mixture was ground for 30 min, and then the slurry was prepared and rolled into a sheet, which was dried in a vacuum oven at 80 ℃ for 12 h, and then cut into a round sheet with a diameter of 10 mm as positive electrode. A metal Mg sheet with a diameter of 14 mm was used as negative electrode, and the magnesium battery was assembled by using the above materials.

[0054] Comparative Example 2 This comparative example provided a Cu 2-x S / MoS2nanosheets, the only difference between the preparation method and Example 1 was that: the reaction temperature was different; The specific process was as follows: 1 mmol CuSCN and 1 mmol MoCl5 were dissolved in 70 mL water, and stirred for 0.5 h to obtain a uniform mixed solution, which was then transferred to a reaction kettle and heated to 220 ℃ for 0.5 h, and then continuously heated to 150 ℃ for 0.5 h. The product was washed with deionized water and ethanol three times, and dried in a vacuum oven at 80 ℃ for 24 h. It was difficult to obtain uniform nanosheets, and MoS2 was difficult to grow epitaxially on the surface thereof.

[0055] Application Example: It can be seen from the XRD of Figure 1 that the Cu 2-x S@MoS2nanoheterojunction synthesized in Example 1 belonged to a triclinic system.

[0056] It can be seen from the TEM of Figure 2 and the HRTEM image of Figure 3 that the Cu 2-x S@MoS2nanoheterojunction synthesized in Example 1 had a uniform hexagonal morphology, and the material particle size was about 15 nm~30 nm.

[0057] It can be seen from the element mapping of Figure 3 that the Cu 2-xIn the S@MoS2 nano-heterojunction, MoS2 is uniformly epitaxially grown on Cu 2–x S surface.

[0058] By Figure 4 EDX map of the element of Cu 2–x S@MoS2 nano-heterojunction, the element ratio of Cu and Mo is about 9:1.

[0059] Assembly and performance test of magnesium battery: Select 0.5 M Mg(TFSI)2 and 1 M MgCl2 dissolved in ethylene glycol dimethyl ether as electrolyte; Cu 2-x S@MoS2 nano-heterojunction as positive active material, Ketjen black as conductive agent, PTFE as binder, and their mass ratio is 6:2:2, the mixture is fully ground for 30 min, the slurry is made and rolled into a sheet, dried in a vacuum oven at 80 DEG C for 12 h, cut into a circle with a diameter of 10 mm as a positive electrode, and a metal Mg sheet with a diameter of 14 mm as a negative electrode. The separator selects whatman GF / D. The above materials are assembled to obtain a magnesium battery.

[0060] The specific assembly process is: according to the order of negative electrode, separator and positive electrode, they are assembled in CR2032 battery shell, 100 microliters of electrolyte is dropped, and the battery is tightly packaged by using battery packaging machine. The packaged battery is tested by charge and discharge in a blue electric test system.

[0061] By Figures 5-10 The battery performance diagram of the element of Cu 2–x S@MoS2 nano-heterostructure has stable voltage platform in charge and discharge curve and high capacity, and the reversible capacity is about xx mAh / g. Its long cycle stability and rate performance are good. It can be stably cycled for more than 200 cycles, and the average capacity decay rate of each cycle is as low as 0.059%. The charge and discharge platform of Cu 2-x S nanosheet synthesized in Comparative Example 1 changes all the time during the charge and discharge process, the capacity is low, the capacity retention rate is only 58.4%, and the rate performance is poor, which only shows a capacity of 8.6 mAh / g at a large current density of 1000 mA / g.

[0062] The present application overcomes the lattice mismatch problem of two different crystal system materials and the uncontrollable problem of epitaxial growth caused by the large difference in bond energy between Mo and Cu and S. The preparation method of the present application has the advantages of simple and controllable process flow, low cost, high repeatability, environmental friendliness, etc.; at the same time, the Cu 2–xThe S@MoS2 nano-heterojunction has regular morphology, excellent structural stability and high ion and electron conductivity, and has excellent electrochemical performance in the rechargeable magnesium battery, and has broad application prospect.

[0063] The foregoing description of the embodiments is for the purpose of enabling a person with ordinary skill in the art to understand and use the invention. Those skilled in the art can easily make various modifications to the embodiments and apply the general principles described herein to other embodiments without creative labor. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art without departing from the scope of the invention should be within the scope of protection of the invention.

Claims

1. A Cu 2–x The method for preparing S@MoS2 nanoheterostructures is characterized by, include: The sulfur-containing copper source and molybdenum source are reacted by heating in an organic solvent to obtain the product.

2. The Cu according to claim 1 2–x The method for preparing S@MoS2 nanoheterostructures is characterized by, The sulfur-containing copper source is CuSCN; the molybdenum source is selected from MoCl5 and (NH4)6Mo7O. 24 Or one of Na2MoO4; The molar ratio of the sulfur-containing copper source and the molybdenum source is 1:0.5~1.

3. The Cu according to claim 1 2–x The method for preparing S@MoS2 nanoheterostructures is characterized by, In the heating reaction, the reaction temperature is 240~260 ℃, the reaction time is 0.5~1 h, and the reaction environment is a nitrogen atmosphere, an inert gas atmosphere, or a vacuum environment; the organic solvent is selected from at least one of oleylamine, 1-octadecene, or oleic acid, and the feed ratio with the sulfur-containing copper source is (15-30) mL:1 mmol.

4. A Cu 2–x The method for preparing S@MoS2 nanoheterostructures is characterized by, include: The copper source, molybdenum source, and sulfur source are reacted by heating in an organic solvent to obtain the product.

5. The Cu according to claim 4 2–x The method for preparing S@MoS2 nanoheterostructures is characterized by, The sulfur-containing copper source is selected from one of halide salts, Cu(acac)2, or Cu(NO3)2; the molybdenum source is selected from MoCl5, (NH4)6Mo7O. 24 Or one of Na2MoO4; the sulfur source is dodecyl mercaptan; the feeding ratio of the copper source, molybdenum source and sulfur source is 1 mmol: 0.5~1 mmol: 5~10 mL.

6. The Cu according to claim 4 2–x The method for preparing S@MoS2 nanoheterostructures is characterized by, In the heating reaction, the reaction temperature is 240~260 ℃, the reaction time is 0.5~1 h, and the reaction environment is a nitrogen atmosphere, an inert gas atmosphere, or a vacuum environment; the organic solvent is selected from at least one of oleylamine, 1-octadecene, or oleic acid, and the feeding ratio with the copper source is (15-30) mL:1 mmol.

7. A Cu 2–x S@MoS2 nanoheterojunction, characterized in that It is prepared by the method described in any one of claims 1 to 6.

8. The Cu according to claim 7 2–x S@MoS2 nanoheterojunction, characterized in that The Cu 2–x The S@MoS2 nanoheterostructure has a particle size of 15 nm to 30 nm. The outer layer of the nanosheet is a monolayer of MoS2 molecules, with S atoms uniformly distributed on both sides of the Mo atoms. The inner layer of S atoms is connected to Cu atoms. 2-x The outer Cu atoms of S are bonded, and the bottom and sides of the nanosheet are covered with MoS2. The ratio of Cu to Mo is 9:

1.

9. A Cu as described in claim 7 or 8 2–x The application of S@MoS2 nanoheterostructures is characterized by... The Cu 2–x S@MoS2 nanoheterojunctions are used as cathode materials in the fabrication of lithium-ion, sodium-ion, or magnesium-ion batteries.

10. The Cu according to claim 9 2–x The application of S@MoS2 nanoheterostructures is characterized by... The method for preparing the magnesium-ion battery includes: An ethylene glycol dimethyl ether solution of Mg(TFSI)2 and MgCl2 was used as the electrolyte; With Cu 2-x The positive electrode is obtained by mixing, grinding, slurry preparation, pressing, and drying S@MoS2 nano-heterojunction as the positive electrode active material, Ketjen black as the conductive agent, and polytetrafluoroethylene as the binder. It was prepared using Mg sheet as the negative electrode; Preferably, the molar concentration of Mg(TFSI)₂ is 0.5~1 M, and the molar concentration of MgCl₂ is 1~1.5 M; the Cu 2-x The mass ratio of S@MoS2 nanoheterojunction, Ketjen black, and polytetrafluoroethylene is 6:2~3:2~3.

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