Method for preparing molybdenum vanadium sulfide heterojunctions with rich sulfur defects pre-embedded with molybdenum ions

Abstract

The application provides a preparation method of a molybdenum ion pre-embedded molybdenum vanadium sulfide heterojunction rich in sulfur defects, comprising the following steps: step 1, dissolving C2H5NS in ethylene glycol to obtain solution A; step 2, dissolving a vanadium source in deionized water to obtain solution B; step 3, mixing solution A obtained in step 1 with solution B obtained in step 2, and then reacting at 70-160 DEG C for 30-120 min, and then naturally cooling to room temperature after the reaction is completed to obtain solution C; step 4, adding a molybdenum source into solution C obtained in step 3, and then obtaining solution D after ultrasonic oscillation, and then transferring solution D into a reaction kettle, and then performing hydrothermal reaction at 160-180 DEG C for 16-20 h, and then naturally cooling to room temperature after the reaction is completed, and then obtaining the molybdenum ion pre-embedded molybdenum vanadium sulfide heterojunction rich in sulfur defects after washing and drying. The method of the application controls VS4 through internal surface interface regulation, provides a novel electrode material for a water-based zinc ion battery, greatly improves the reversible capacity of the battery, and prolongs the cycle life of the battery.

Description

Technical Field

[0001] This invention belongs to the field of aqueous zinc-ion battery technology, and relates to heterojunctions, specifically to a method for preparing a molybdenum ion pre-intercalated molybdenum vanadium sulfide heterojunction rich in sulfur defects. Background Technology

[0002] Aqueous zinc-ion batteries are high-energy-density aqueous secondary battery systems, but due to Zn... 2+ Zn is a multivalent ion with a high charge number and large atomic weight, exhibiting strong electrostatic repulsion. Furthermore, in aqueous solution, Zn... 2+ Generally existing in the form of hydrated ions, with a relatively large actual ionic radius, this means that cathode materials suitable for lithium-ion batteries cannot be directly applied to aqueous zinc-ion batteries. Therefore, cathode materials for aqueous zinc-ion batteries are currently very scarce.

[0003] Currently, most materials used as cathodes in aqueous zinc-ion batteries fall into three categories: vanadium-based, manganese-based, and Prussian blue compounds. Among these, vanadium-based compounds are considered the most promising and suitable for large-scale production due to the high abundance and low price of vanadium. Based on the valence state of vanadium, tetravalent, pentavalent, and intermediate valence vanadium-based compounds are mainly used in aqueous zinc-ion batteries. VS4, with its chain-like structure, has been shown to allow Zn to pass through its lattice. 2+ Diffusion and migration result in excellent theoretical capacity. However, due to the volume effect caused by ion insertion during energy storage, VS4 exhibits poor actual energy storage properties when used as the cathode of aqueous zinc-ion batteries. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a method for preparing a molybdenum ion pre-intercalated molybdenum vanadium sulfide heterojunction rich in sulfur defects, thereby solving the technical problem that the energy storage performance of electrode materials prepared by existing methods needs further improvement when used in aqueous zinc-ion batteries.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] A method for preparing a sulfur-defect-rich molybdenum ion pre-intercalated molybdenum-vanadium sulfide heterojunction, the method comprising the following steps:

[0007] Step 1: Dissolve C2H5NS in ethylene glycol to obtain solution A.

[0008] Step 2: Dissolve the vanadium source in deionized water to obtain solution B.

[0009] Step 3: Mix solution A obtained in step 1 with solution B obtained in step 2 and react at 70-160℃ for 30-120 minutes. After the reaction is completed, allow it to cool naturally to room temperature to obtain solution C.

[0010] Step 4: Add the molybdenum source to solution C obtained in step 3, and after ultrasonic vibration, obtain solution D. Transfer it to a reaction vessel and carry out a hydrothermal reaction at 160-180℃ for 16-20 hours. After the reaction is completed, allow it to cool naturally to room temperature. After washing and drying, obtain a sulfur-defect-rich molybdenum ion pre-intercalated molybdenum vanadium sulfide heterojunction.

[0011] The present invention also has the following technical features:

[0012] Preferably, in step 1, the concentration of C2H5NS in solution A is 0.6–3 mol / L.

[0013] Preferably, in step 2, the temperature of the deionized water is 70°C.

[0014] Preferably, in step 2, the vanadium source is NH4VO3, K3VO4, or Na3VO4.

[0015] Preferably, in step 2, the concentration of vanadate in the vanadium source in solution B is 0.1–0.5 mol / L.

[0016] Preferably, in step 3, the concentration of C2H5NS in solution C is 0.3–1.5 mol / L, and the concentration of vanadate in solution C is 0.05–0.25 mol / L.

[0017] Preferably, in step 4, the molybdenum source is Na₂MoO₄, K₂MoO₄, or (NH₄)₆Mo₇O₄. 24 .

[0018] Preferably, in step 4, the Mo in the molybdenum source... 6+ The concentration in solution D is 0.0005–0.075 mol / L.

[0019] Preferably, in step 4, the washing is performed with deionized water and ethanol, and the drying is performed by vacuum drying the precipitate at 50-60°C.

[0020] The preferred method includes the following steps:

[0021] Step 1: Weigh 18 mmol of C2H5NS and add it to 30 mL of ethylene glycol to dissolve and form a transparent solution A. The concentration of C2H5NS in solution A is 0.6 mol / L.

[0022] Step 2: Weigh 3 mmol of NH4VO3 and add it to 30 mL of deionized water at 70 °C to dissolve and form a transparent solution B. The concentration of vanadate in solution B is 0.1 mol / L.

[0023] Step 3: Mix solution A and solution B and react at 70°C for 120 minutes to obtain solution C.

[0024] Step 4: Weigh 0.0043 mmol of (NH4)6Mo7O 24 Add to solution C, sonicate and vibrate to dissolve and form a transparent solution D. The concentration of C2H5NS in solution D is 0.3 mol / L, the concentration of vanadate is 0.05 mol / L, and the concentration of Mo is... 6+ The concentration is 0.0005 mol / L.

[0025] Solution D was transferred to a stainless steel reactor lined with polytetrafluoroethylene and reacted at 160°C for 18 hours. After the reaction was completed, the mixture was naturally cooled to room temperature and washed four times each with deionized water and ethanol. The precipitate was then vacuum dried at 50–60°C to obtain the final product, a molybdenum ion pre-intercalated molybdenum vanadium sulfide heterojunction rich in sulfur defects.

[0026] Compared with the prior art, the present invention has the following technical effects:

[0027] (I) The method of the present invention provides a novel electrode material for aqueous zinc-ion batteries by regulating VS4 through the internal surface interface, which greatly improves the reversible capacity of the battery and extends the cycle life of the battery.

[0028] (II) In the method of the present invention, appropriate molybdenum ions are introduced during the generation of VS4, so that the molybdenum ions are pre-embedded into the interlayer of the VS4 lattice, thereby increasing the interlayer spacing of VS4.

[0029] (III) In the method of the present invention, when the molybdenum ions reach a certain concentration, the pre-embedded molybdenum ions and sulfur ions generate MoS2, and the vanadium ions and sulfur ions generate VS4. MoS2 and VS4 construct a heterojunction.

[0030] (IV) In the method of the present invention, the reducing power of ethylene glycol can generate a large number of sulfur defects at the same time as the molybdenum vanadium sulfide is generated.

[0031] (V) In summary, the method of the present invention increases the interlayer spacing of vanadium-sulfur compounds, constructs a molybdenum-vanadium sulfide heterojunction, and has sulfur defects. These three factors work together to enhance the energy storage characteristics of the electrode material when used as an aqueous zinc-ion battery. Attached Figure Description

[0032] Figure 1 This is the X-ray diffraction pattern of the sulfur-defect-rich molybdenum ion pre-intercalated molybdenum vanadium sulfide heterojunction prepared in Example 1.

[0033] Figure 2 This is a scanning electron microscope image of the sulfur-defect-rich molybdenum ion pre-intercalated molybdenum vanadium sulfide heterojunction prepared in Example 1.

[0034] Figure 3 This is an elemental mapping image of the molybdenum ion pre-intercalated molybdenum vanadium sulfide heterojunction of the product of Example 1.

[0035] Figure 4 This is a rate performance diagram of the sulfur-defect-rich molybdenum ion pre-intercalated molybdenum vanadium sulfide heterojunction cathode material prepared in Example 1.

[0036] Figure 5 This is a cycle performance diagram of the sulfur-defect-rich molybdenum ion pre-intercalated molybdenum vanadium sulfide heterojunction cathode material prepared in Example 1.

[0037] The specific content of the present invention will be further explained in detail below with reference to the embodiments. Detailed Implementation

[0038] It should be noted that, unless otherwise specified, all raw materials used in this invention are those known in the prior art.

[0039] This invention provides a method for preparing a sulfur-defect-rich molybdenum ion pre-intercalated molybdenum-vanadium sulfide heterojunction, comprising: dissolving C2H5NS in ethylene glycol to obtain solution A; dissolving a vanadium source in deionized water (70°C) to obtain solution B; mixing solutions A and B and reacting at 70-160°C for 30-120 min to obtain solution C; adding a molybdenum source to solution C, ultrasonically vibrating to obtain solution D, transferring to a polytetrafluoroethylene-lined stainless steel reactor for hydrothermal reaction, and after cleaning and drying, obtaining a sulfur-defect-rich molybdenum ion pre-intercalated molybdenum-vanadium sulfide heterojunction. This method utilizes the pre-intercalation of molybdenum ions to increase the interlayer spacing of vanadium sulfide; at appropriate concentrations, molybdenum and vanadium ions react with sulfur ions to form molybdenum-vanadium sulfide, constructing a heterojunction; and utilizing the reducing properties of ethylene glycol to generate sulfur defects. These three factors work together to enhance the energy storage characteristics of this electrode material when used in aqueous zinc-ion batteries, achieving energy storage capacities up to 10 A g. －1 At a high current density, with 192mAh g －1 The initial reversible capacity cycle is 500 times.

[0040] Following the above technical solutions, specific embodiments of the present invention are given below. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent modifications made based on the technical solutions of this application fall within the protection scope of the present invention.

[0041] Example 1:

[0042] This embodiment provides a method for preparing a molybdenum ion pre-intercalated molybdenum vanadium sulfide heterojunction rich in sulfur defects, characterized by the following steps:

[0043] Weigh 18 mmol of C2H5NS and add it to 30 mL of ethylene glycol to dissolve and form a clear solution A with a C2H5NS concentration of 0.6 mol / L. Weigh 3 mmol of NH4VO3 and add it to 30 mL of deionized water at 70 °C to dissolve and form a clear solution B with a vanadate concentration of 0.1 mol / L. Mix equal volumes of solutions A and B and react at 70 °C for 120 min to obtain solution C. Weigh 0.0043 mmol of (NH4)6Mo7O 24 Add to solution C, sonicate and vibrate to dissolve and form a transparent solution D. The concentration of C2H5NS in solution D is 0.3 mol / L, the concentration of vanadate is 0.05 mol / L, and the concentration of Mo is... 6+ The concentration was 0.0005 mol / L. Solution D was transferred to a stainless steel reactor lined with polytetrafluoroethylene and reacted at 160°C for 18 h. After the reaction was completed, it was naturally cooled to room temperature and washed 4 times each with deionized water and ethanol. The precipitate was then vacuum dried at 50-60°C to obtain the final product, a molybdenum ion pre-intercalated molybdenum vanadium sulfide heterojunction rich in sulfur defects.

[0044] Figure 1 The X-ray diffraction (XRD) pattern of the molybdenum ion pre-intercalated molybdenum vanadium sulfide heterojunction obtained in Example 1 of this invention corresponds to the standard card of VS4 (JCPDS No. 71-2499). No other impurity peaks appear, indicating that Mo... 6+ The results have been pre-embedded in VS4; the sharp diffraction peaks indicate that the obtained product has high crystallinity.

[0045] Figure 2 This is a scanning electron microscope (SEM) image of the molybdenum ion pre-intercalated molybdenum vanadium sulfide heterojunction produced in Example 1 of this invention. As can be seen from the image, the prepared sample consists of uniform nanospheres with a diameter of 300–600 nm.

[0046] Figure 3 These are elemental mapping images of the molybdenum ion pre-intercalated molybdenum vanadium sulfide heterojunction produced in Example 1 of this invention. The images show the Mo ions in the prepared spherical VS4. 6+ Successful pre-embedding, with elements evenly distributed.

[0047] The sulfur-defect-rich molybdenum ion pre-intercalated molybdenum vanadium sulfide heterojunction prepared in this embodiment is used to prepare the cathode material for aqueous zinc-ion batteries.

[0048] Figure 4 The rate performance of an aqueous zinc-ion battery prepared from the molybdenum ion pre-intercalated molybdenum vanadium sulfide heterojunction of Example 1 in this invention is measured at current densities of 0.1, 0.5, 1, 2, 4, 8, and 16 Ag. －1 The following are available in approximately 226, 224, 216, 207, 196, 194 and 183 mAh g respectively. －1 High reversible capacity, and when the current density returns to 0.1Ag －1 At that time, the capacity can gradually recover to 190, 194, 202, 211, 218 and 220 mAhg. －1 High reversible capacity

[0049] Figure 5 To demonstrate the long-cycle performance of an aqueous zinc-ion battery prepared from the molybdenum ion pre-intercalated molybdenum vanadium sulfide heterojunction of Example 1 in this invention, at 10 A g... －1 At a high current density, with 192mAh g －1 The initial reversible capacity remains at 164 mAh g after 500 cycles. －1 The capacity retention rate is as high as 85.4%. Therefore, the preparation method provided in this invention can effectively prepare high-performance cathode materials suitable for aqueous zinc-ion batteries.

[0050] Example 2:

[0051] This embodiment provides a method for preparing a molybdenum ion pre-intercalated molybdenum vanadium sulfide heterojunction rich in sulfur defects, characterized by the following steps:

[0052] 18 mmol of C₂H₅NS was added to 30 mL of ethylene glycol and dissolved to form a clear solution A with a C₂H₅NS concentration of 0.6 mol / L. 3 mmol of K₃VO₄ was added to 30 mL of deionized water at 70 °C and dissolved to form a clear solution B with a vanadate concentration of 0.1 mol / L. Solutions A and B were mixed and reacted at 120 °C for 60 min to obtain solution C. 0.03 mmol of K₂MoO₄ was added to solution C and sonicated to dissolve and form a clear solution D with a C₂H₅NS concentration of 0.3 mol / L, a vanadate concentration of 0.05 mol / L, and a MoO₄ concentration of 0.05 mol / L. 6+The concentration was 0.0005 mol / L. Solution D was transferred to a stainless steel reactor lined with polytetrafluoroethylene and reacted at 160°C for 18 h. After the reaction was completed, it was naturally cooled to room temperature and washed 4 times each with deionized water and ethanol. The precipitate was then vacuum dried at 50-60°C to obtain the final product, a molybdenum ion pre-intercalated molybdenum vanadium sulfide heterojunction rich in sulfur defects.

[0053] The morphology of the sulfur-defect-rich molybdenum ion pre-intercalated molybdenum vanadium sulfide heterojunction prepared in this embodiment is basically the same as that in Example 1.

[0054] The sulfur-defect-rich molybdenum ion pre-intercalated molybdenum vanadium sulfide heterojunction prepared in this embodiment is used to prepare the cathode material for aqueous zinc-ion batteries.

[0055] The molybdenum ion pre-intercalated molybdenum vanadium sulfide heterojunction cathode material prepared in this embodiment with sulfur defects was subjected to the same performance test as in Example 1, and showed that it had the same relatively excellent specific capacity, cycle performance and rate performance as in Example 1.

[0056] Example 3:

[0057] This embodiment provides a method for preparing a molybdenum ion pre-intercalated molybdenum vanadium sulfide heterojunction rich in sulfur defects, characterized by the following steps:

[0058] 18 mmol of C₂H₅NS was added to 30 mL of ethylene glycol and dissolved to form a clear solution A with a C₂H₅NS concentration of 0.6 mol / L. 3 mmol of Na₃VO₄ was added to 30 mL of deionized water at 70 °C and dissolved to form a clear solution B with a vanadate concentration of 0.1 mol / L. Solutions A and B were mixed and reacted at 160 °C for 30 min to obtain solution C. 0.03 mmol of Na₂MoO₄ was added to solution C and sonicated to dissolve and form a clear solution D with a C₂H₅NS concentration of 0.3 mol / L, a vanadate concentration of 0.05 mol / L, and a Mo₂O₄ concentration of 0.05 mol / L. 6+ The concentration was 0.0005 mol / L. Solution D was transferred to a stainless steel reactor lined with polytetrafluoroethylene and reacted at 160°C for 18 h. After the reaction was completed, it was naturally cooled to room temperature and washed 4 times each with deionized water and ethanol. The precipitate was then vacuum dried at 50-60°C to obtain the final product, a molybdenum ion pre-intercalated molybdenum vanadium sulfide heterojunction rich in sulfur defects.

[0059] The morphology of the sulfur-defect-rich molybdenum ion pre-intercalated molybdenum vanadium sulfide heterojunction prepared in this embodiment is basically the same as that in Example 1.

[0060] The sulfur-defect-rich molybdenum ion pre-intercalated molybdenum vanadium sulfide heterojunction prepared in this embodiment is used to prepare the cathode material for aqueous zinc-ion batteries.

[0061] The molybdenum ion pre-intercalated molybdenum vanadium sulfide heterojunction cathode material prepared in this embodiment with sulfur defects was subjected to the same performance test as in Example 1, and showed that it had the same relatively excellent specific capacity, cycle performance and rate performance as in Example 1.

[0062] Example 4:

[0063] This embodiment provides a method for preparing a molybdenum ion pre-intercalated molybdenum vanadium sulfide heterojunction rich in sulfur defects, characterized by the following steps:

[0064] Weigh 36 mmol of C2H5NS and add it to 30 mL of ethylene glycol to dissolve and form a clear solution A with a C2H5NS concentration of 1.2 mol / L. Weigh 6 mmol of NH4VO3 and add it to 30 mL of deionized water at 70 °C to dissolve and form a clear solution B with a vanadate concentration of 0.2 mol / L. Mix equal volumes of solutions A and B and react at 70 °C for 120 min to obtain solution C. Weigh 0.0428 mmol of (NH4)6Mo7O 24 Add to solution C, sonicate and vibrate to dissolve and form a transparent solution D. The concentration of C2H5NS in solution D is 0.6 mol / L, the concentration of vanadate is 0.1 mol / L, and the concentration of Mo is... 6+ The concentration was 0.005 mol / L. Solution D was transferred to a stainless steel reactor lined with polytetrafluoroethylene and reacted at 160°C for 18 h. After the reaction was completed, it was naturally cooled to room temperature and washed 4 times each with deionized water and ethanol. The precipitate was dried under vacuum at 50-60°C to obtain the final product, a molybdenum ion pre-intercalated molybdenum vanadium sulfide heterojunction rich in sulfur defects.

[0065] The morphology of the sulfur-defect-rich molybdenum ion pre-intercalated molybdenum vanadium sulfide heterojunction prepared in this embodiment is basically the same as that in Example 1.

[0066] The sulfur-defect-rich molybdenum ion pre-intercalated molybdenum vanadium sulfide heterojunction prepared in this embodiment is used to prepare the cathode material for aqueous zinc-ion batteries.

[0067] The molybdenum ion pre-intercalated molybdenum vanadium sulfide heterojunction cathode material prepared in this embodiment with sulfur defects was subjected to the same performance test as in Example 1, and showed that it had the same relatively excellent specific capacity, cycle performance and rate performance as in Example 1.

[0068] Example 5:

[0069] This embodiment provides a method for preparing a molybdenum ion pre-intercalated molybdenum vanadium sulfide heterojunction rich in sulfur defects, characterized by the following steps:

[0070] Weigh 54 mmol of C2H5NS and add it to 30 mL of ethylene glycol to dissolve and form a clear solution A with a C2H5NS concentration of 1.8 mol / L. Weigh 9 mmol of NH4VO3 and add it to 30 mL of deionized water at 70 °C to dissolve and form a clear solution B with a vanadate concentration of 0.3 mol / L. Mix equal volumes of solutions A and B and react at 70 °C for 120 min to obtain solution C. Weigh 0.1286 mmol of (NH4)6Mo7O 24 Add to solution C, sonicate and vibrate to dissolve and form a transparent solution D. The concentration of C2H5NS in solution D is 0.9 mol / L, the concentration of vanadate is 0.15 mol / L, and the concentration of Mo is... 6+ The concentration was 0.015 mol / L. Solution D was transferred to a stainless steel reactor lined with polytetrafluoroethylene and reacted at 160°C for 18 h. After the reaction was completed, it was naturally cooled to room temperature and washed 4 times each with deionized water and ethanol. The precipitate was then vacuum dried at 50-60°C to obtain the final product, a molybdenum ion pre-intercalated molybdenum vanadium sulfide heterojunction rich in sulfur defects.

[0071] The morphology of the sulfur-defect-rich molybdenum ion pre-intercalated molybdenum vanadium sulfide heterojunction prepared in this embodiment is basically the same as that in Example 1.

[0072] The sulfur-defect-rich molybdenum ion pre-intercalated molybdenum vanadium sulfide heterojunction prepared in this embodiment is used to prepare the cathode material for aqueous zinc-ion batteries.

[0073] The molybdenum ion pre-intercalated molybdenum vanadium sulfide heterojunction cathode material prepared in this embodiment with sulfur defects was subjected to the same performance test as in Example 1, and showed that it had the same relatively excellent specific capacity, cycle performance and rate performance as in Example 1.

[0074] Example 6:

[0075] This embodiment provides a method for preparing a molybdenum ion pre-intercalated molybdenum vanadium sulfide heterojunction rich in sulfur defects, characterized by the following steps:

[0076] Weigh 72 mmol of C2H5NS and add it to 30 mL of ethylene glycol to dissolve and form a clear solution A with a C2H5NS concentration of 2.4 mol / L. Weigh 9 mmol of NH4VO3 and add it to 30 mL of deionized water at 70 °C to dissolve and form a clear solution B with a vanadate concentration of 0.3 mol / L. Mix equal volumes of solutions A and B and react at 70 °C for 120 min to obtain solution C. Weigh 0.3857 mmol of (NH4)6Mo7O 24Add to solution C, sonicate and vibrate to dissolve and form a transparent solution D. The concentration of C2H5NS in solution D is 1.2 mol / L, the concentration of vanadate is 0.15 mol / L, and the concentration of Mo is... 6+ The concentration was 0.045 mol / L. Solution D was transferred to a stainless steel reactor lined with polytetrafluoroethylene and reacted at 160°C for 18 h. After the reaction was completed, it was naturally cooled to room temperature and washed 4 times each with deionized water and ethanol. The precipitate was dried under vacuum at 50-60°C to obtain the final product, a molybdenum ion pre-intercalated molybdenum vanadium sulfide heterojunction rich in sulfur defects.

[0077] The morphology of the sulfur-defect-rich molybdenum ion pre-intercalated molybdenum vanadium sulfide heterojunction prepared in this embodiment is basically the same as that in Example 1.

[0078] The sulfur-defect-rich molybdenum ion pre-intercalated molybdenum vanadium sulfide heterojunction prepared in this embodiment is used to prepare the cathode material for aqueous zinc-ion batteries.

[0079] The molybdenum ion pre-intercalated molybdenum vanadium sulfide heterojunction cathode material prepared in this embodiment with sulfur defects was subjected to the same performance test as in Example 1, and showed that it had the same relatively excellent specific capacity, cycle performance and rate performance as in Example 1.

[0080] Example 7:

[0081] This embodiment provides a method for preparing a molybdenum ion pre-intercalated molybdenum vanadium sulfide heterojunction rich in sulfur defects, characterized by the following steps:

[0082] Weigh 90 mmol of C2H5NS and add it to 30 mL of ethylene glycol to dissolve and form a clear solution A with a C2H5NS concentration of 3 mol / L. Weigh 9 mmol of NH4VO3 and add it to 30 mL of deionized water at 70 °C to dissolve and form a clear solution B with a vanadate concentration of 0.3 mol / L. Mix equal volumes of solutions A and B and react at 70 °C for 120 min to obtain solution C. Weigh 0.6428 mmol of (NH4)6Mo7O 24 Add to solution C, sonicate and vibrate to dissolve and form a transparent solution D. Solution D has a C2H5NS concentration of 1.5 mol / L, a vanadate concentration of 0.15 mol / L, and a Mo concentration of... 6+ The concentration was 0.075 mol / L. Solution D was transferred to a stainless steel reactor lined with polytetrafluoroethylene and reacted at 160°C for 18 h. After the reaction was completed, it was naturally cooled to room temperature and washed 4 times each with deionized water and ethanol. The precipitate was dried under vacuum at 50-60°C to obtain the final product, a molybdenum ion pre-intercalated molybdenum vanadium sulfide heterojunction rich in sulfur defects.

[0083] The morphology of the sulfur-defect-rich molybdenum ion pre-intercalated molybdenum vanadium sulfide heterojunction prepared in this embodiment is basically the same as that in Example 1.

[0084] The sulfur-defect-rich molybdenum ion pre-intercalated molybdenum vanadium sulfide heterojunction prepared in this embodiment is used to prepare the cathode material for aqueous zinc-ion batteries.

[0085] The molybdenum ion pre-intercalated molybdenum vanadium sulfide heterojunction cathode material prepared in this embodiment with sulfur defects was subjected to the same performance test as in Example 1, and showed that it had the same relatively excellent specific capacity, cycle performance and rate performance as in Example 1.

[0086] Example 8:

[0087] This embodiment provides a method for preparing a molybdenum ion pre-intercalated molybdenum vanadium sulfide heterojunction rich in sulfur defects, characterized by the following steps:

[0088] Weigh 90 mmol of C2H5NS and add it to 30 mL of ethylene glycol to dissolve and form a clear solution A with a C2H5NS concentration of 3 mol / L. Weigh 15 mmol of NH4VO3 and add it to 30 mL of deionized water at 70 °C to dissolve and form a clear solution B with a vanadate concentration of 0.5 mol / L. Mix equal volumes of solutions A and B and react at 70 °C for 120 min to obtain solution C. Weigh 0.1071 mmol of (NH4)6Mo7O 24 Add to solution C, sonicate and vibrate to dissolve and form a transparent solution D. The concentration of C2H5NS in solution D is 1.5 mol / L, the concentration of vanadate is 0.25 mol / L, and the concentration of Mo is... 6+ The concentration was 0.0125 mol / L. Solution D was transferred to a stainless steel reactor lined with polytetrafluoroethylene and reacted at 160°C for 18 h. After the reaction was completed, it was naturally cooled to room temperature and washed 4 times each with deionized water and ethanol. The precipitate was dried under vacuum at 50-60°C to obtain the final product, a molybdenum ion pre-intercalated molybdenum vanadium sulfide heterojunction rich in sulfur defects.

[0089] The morphology of the sulfur-defect-rich molybdenum ion pre-intercalated molybdenum vanadium sulfide heterojunction prepared in this embodiment is basically the same as that in Example 1.

[0090] The sulfur-defect-rich molybdenum ion pre-intercalated molybdenum vanadium sulfide heterojunction prepared in this embodiment is used to prepare the cathode material for aqueous zinc-ion batteries.

[0091] The molybdenum ion pre-intercalated molybdenum vanadium sulfide heterojunction cathode material prepared in this embodiment with sulfur defects was subjected to the same performance test as in Example 1, and showed that it had the same relatively excellent specific capacity, cycle performance and rate performance as in Example 1.

Claims

1. A method for the preparation of molybdenum ion pre-embedded molybdenum vanadium sulfide heterojunctions rich in sulfur defects, characterized in that, The method includes the following steps: Step 1: Weigh 18 mmol of C2H5NS and add it to 30 mL of ethylene glycol to dissolve and form a transparent solution A. The concentration of C2H5NS in solution A is 0.6 mol / L. Step 2: Weigh 3 mmol of NH4VO3 and add it to 30 mL of deionized water at 70 °C to dissolve and form a transparent solution B. The concentration of vanadate in solution B is 0.1 mol / L. Step 3: Mix solution A and solution B and react at 70°C for 120 min to obtain solution C; Step 4, 0.0043 mmol of (NH4)6Mo7O24*4H2O was weighed 24 Solution C was added into the solution, ultrasonic vibration, dissolved to form a transparent solution D, the concentration of C2H5NS in solution D was 0.3 mol / L, the concentration of vanadate was 0.05 mol / L, Mo 6+ The concentration was 0.0005 mol / L; Solution D was transferred to a stainless steel reactor lined with polytetrafluoroethylene and reacted at 160°C for 18 hours. After the reaction was completed, the mixture was naturally cooled to room temperature and washed four times each with deionized water and ethanol. The precipitate was then vacuum dried at 50–60°C to obtain the final product, a molybdenum ion pre-intercalated molybdenum vanadium sulfide heterojunction rich in sulfur defects.

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