A bimetallic sulfur-oxygen compound, its preparation method and use

Abstract

The application discloses a bimetallic sulfur-oxygen compound and a preparation method and application thereof, and belongs to the technical field of sodium ion battery electrode materials. The preparation method disclosed by the application adopts molybdenum salt, zinc salt and sulfur powder as raw materials, modifies the morphology and nano structure of a traditional sodium ion battery metal oxide negative electrode material, adds a bimetallic sulfide to obtain a composite material of an ultrathin two-dimensional nanosheet vertically interwoven to constitute a three-dimensional nano structure, and can play the roles of improving the electric conductivity, increasing active sites and stabilizing the nano structure of the electrode material, and improves the electrochemical activity of the electrode material.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of sodium ion battery electrode materials, and particularly relates to a bimetallic sulfur-oxygen compound and a preparation method and application thereof. BACKGROUND

[0002] As a new emerging electrochemical energy storage technology, sodium ion batteries have attracted extensive attention in recent years due to the relatively abundant sodium resources and low cost. The metal oxide negative materials of sodium ion batteries generally have the characteristics of abundant resources, high theoretical specific capacity and environmental friendliness, but also have the problems of low electrical conductivity, volume expansion and voltage hysteresis, which limit their large-scale application. The research on the metal oxide negative materials of sodium ion batteries is continuously progressing, and through material modification, structure design and electrolyte optimization, it is expected to improve the electrochemical performance and overcome the existing shortcomings.

[0003] A Chinese patent application with the patent number CN106115785A discloses a pure phase molybdenum dioxide prepared by a self-reduction reaction of ammonia gas produced by thermal decomposition of ammonium molybdate, as a technical solution of sodium ion battery negative material. Although its initial discharge specific capacity reaches about 930 mAh / g at a current density of 0.05 A / g, its reversible charge specific capacity is relatively low, only about 300 mAh / g. A Chinese patent application with the patent number CN112310385A discloses a technical solution of assembling silver ear-shaped nanoball sodium ion battery negative material by embedding molybdenum dioxide nanoparticles in carbon nanosheets. Although its initial discharge specific capacity is relatively low, about 730 mAh / g, it effectively improves its reversible charge specific capacity, about 550 mAh / g. In addition, as a metal sulfide negative material of sodium ion battery, molybdenum disulfide has relatively high electrical conductivity and working voltage, but its electrochemical activity still needs to be further improved, and it also has the problem of rapid capacity decay caused by volume expansion. A Chinese patent application with the patent number CN112599752A prepares a carbon-coated hollow kapok fiber supported flower-like molybdenum disulfide composite material as a sodium ion battery negative material, and its initial discharge / charge specific capacity is only about 618 / 404 mAh / g at a current density of 0.05 A / g, and the initial coulombic efficiency is 65%. SUMMARY

[0004] The purpose of the present application is to provide a bimetallic sulfur-oxygen compound and a preparation method and application thereof, to solve the technical problem of low electrochemical activity of existing sodium ion battery electrode materials.

[0005] In order to achieve the above purpose, the technical scheme is adopted as follows:

[0006] The application discloses a preparation method of a bimetallic sulfur-oxygen compound, comprising the following steps:

[0007] After mixing the molybdenum salt, the zinc salt and the solvent, solution A is obtained;

[0008] After mixing the complexing agent and the solvent, solution B is obtained;

[0009] After mixing solution A and solution B at room temperature and stirring, the product is obtained after collecting the precipitate, cleaning and drying in sequence;

[0010] After mixing the product and sulfur powder and calcining, the bimetallic sulfur-oxygen compound is obtained.

[0011] Further, the molybdenum salt is one of ammonium molybdate, sodium molybdate and potassium molybdate; the zinc salt is one of zinc nitrate, zinc sulfate and zinc chloride.

[0012] Further, the complexing agent is one of 2-ethyl-4-methylimidazole, 2-hydroxymethyl-1-methylimidazole and 1-methyl-2-chloromethylimidazole; the solvent is anhydrous methanol.

[0013] Further, in solution A, the amount ratio of the molybdenum salt, the zinc salt and the solvent is (1-3) mmol:(1-3) mmol:(10-20) mL.

[0014] Further, in solution B, the amount ratio of the complexing agent and the solvent is (20-40) mmol:(40-80) mL.

[0015] Further, the stirring time is 24-48 h.

[0016] Further, before mixing the product and sulfur powder and calcining, the product is pretreated in a tube furnace; the pretreatment temperature is 200-400 DEG C and the pretreatment time is 2-4 h.

[0017] Further, the mass ratio of the product and sulfur powder is 1:(2-4); the calcination temperature is 500-700 DEG C and the calcination time is 2-4 h.

[0018] The application further discloses the bimetallic sulfur-oxygen compound prepared by the preparation method.

[0019] The application further discloses application of the bimetallic sulfur-oxygen compound in an electrode material of a sodium ion battery.

[0020] Compared with the prior art, the application has the following beneficial effects:

[0021] The application discloses a preparation method of a bimetallic sulfur-oxygen compound, which adopts molybdenum salt, zinc salt and sulfur powder as raw materials, modifies the morphology and nanostructure of a traditional sodium ion battery metal oxide negative electrode material, adds bimetallic sulfide to obtain a composite material of ultrathin two-dimensional nanosheets vertically interwoven to constitute a three-dimensional nanostructure, and can play the roles of improving conductivity, increasing active sites and stabilizing the nanostructure of the electrode material, thereby improving the electrochemical activity of the electrode material.

[0022] Further, the bimetallic heterostructure constructed in combination with zinc sulfide can play the roles of dispersing stress and relieving the volume change of the electrode material in the sodium intercalation and deintercalation process, and the three roles are synergistic, thereby further improving the electrochemical sodium storage activity of the composite electrode material.

[0023] Further, the raw materials of the method are all industrial grade, are rich in source, are low in cost, are harmless to the environment and human bodies, the preparation process is simple, the requirement for equipment is low, the method is strong in repeatability, no waste water or waste liquid is generated, and the process is green and environment-friendly.

[0024] The application further discloses the bimetallic sulfur-oxygen compound prepared by the method, and the prepared product is good in crystallinity, special in morphology structure and high in electrochemical sodium storage activity. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 FIG. 1 is an SEM image of the bimetallic sulfur-oxygen compound prepared by the method of the application;

[0026] Figure 2 FIG. 2 is an XRD image of the bimetallic sulfur-oxygen compound prepared by the method of the application;

[0027] Figure 3 FIG. 3 is a charge-discharge curve of the bimetallic sulfur-oxygen compound prepared by the method of the application. DETAILED DESCRIPTION

[0028] To enable those skilled in the art to understand the features and effects of the application, the following is a general description and definition of the terms and phrases mentioned in the specification and claims. Unless otherwise specified, all technical and scientific words used in the specification are the usual meanings understood by those skilled in the art of the application, and when there is a conflict, the definition in the specification shall prevail.

[0029] Theories or mechanisms described and disclosed herein, whether correct or not, should not be used to limit the scope of the application, that is, the content of the application can be implemented without being limited by any specific theory or mechanism.

[0030] Herein, all features defined by a numerical range or a percentage range, such as numerical values, amounts, contents and concentrations, are merely for the sake of brevity and convenience. Accordingly, the description of a numerical range or a percentage range should be considered to have encompassed and specifically disclosed all possible sub-ranges and individual numerical values (including integers and fractions) within the range.

[0031] Herein, unless otherwise specifically stated, "comprise", "include", "contain", "have" or similar terms are used inclusively, in a manner consistent with the way these terms are used in the field of patent claims, and for example "A comprises a" encompasses both "A comprises a and other" and "A comprises only a".

[0032] Herein, for the sake of brevity, all possible combinations of the various technical features in the various embodiments or examples are not described. Therefore, the various technical features in the various embodiments or examples can be combined with each other in any manner as long as there is no contradiction, and all possible combinations should be considered as falling within the scope of the present specification.

[0033] The present application provides a preparation method of a double-metal sulfur-oxygen compound, comprising the following steps:

[0034] S1: preparing solution A by ultrasonically dissolving equimolar molybdenum salt and zinc salt (1-3 mmol) in 10-20 mL of anhydrous methanol;

[0035] S2: preparing solution B by ultrasonically dissolving 20-40 mmol of a complexing agent in 40-80 mL of anhydrous methanol;

[0036] S3: quickly mixing solution A and B, stirring at room temperature for 24 h, collecting the precipitate after the reaction is completed, washing and drying;

[0037] S4: pretreating the above product with a tube furnace, adding sulfur powder after cooling, and obtaining the double-metal sulfur-oxygen compound after calcination.

[0038] Preferably, in S1, the molybdenum salt and the zinc salt include, but are not limited to, ammonium molybdate, sodium molybdate, potassium molybdate, zinc nitrate, zinc sulfate, zinc chloride.

[0039] Preferably, in S2, the complexing agent includes, but is not limited to, 2-ethyl-4-methylimidazole, 2-hydroxymethyl-1-methylimidazole, 1-methyl-2-chloromethylimidazole.

[0040] Preferably, in S4, the pretreatment temperature is 200-400°C, and the pretreatment time is 2-4 h.

[0041] Preferably, in S4, the mass ratio of the precursor solid product to the sulfur powder is 1:(2-4).

[0042] Preferably, the calcination temperature in S4 is 500-700°C, and the calcination time is 2-4h.

[0043] The bimetallic sulfur-oxygen compound prepared by the preparation method has a vertical interweaving structure composed of ultra-thin two-dimensional nanosheets, and the thickness of the nanosheets is 20 nm.

[0044] The application will be further described in conjunction with specific examples. It should be understood that these examples are only used to illustrate the application and not used to limit the scope of the application. Furthermore, it should be understood that those skilled in the art can make various modifications or changes to the application after reading the content of the application, and these equivalent forms also fall within the scope defined by the appended claims.

[0045] The following examples use the conventional instruments and equipment in the art. The experimental methods in the following examples, unless otherwise specified, are usually carried out according to the conventional conditions, or according to the conditions recommended by the manufacturers. Various raw materials are used in the following examples, unless otherwise specified, and the conventional commercially available products are used, and the specifications are conventional specifications in the art. In the specification of the application and the following examples, unless otherwise specified, “%” means weight percent, “parts” means weight parts, and the ratio means weight ratio.

[0046] Example 1

[0047] A preparation method of a bimetallic sulfur-oxygen compound, comprising the following steps:

[0048] S1: 3 mmol of ammonium molybdate (molybdenum salt) and 3 mmol of zinc nitrate (zinc salt) are ultrasonically dissolved in 20 mL of anhydrous methanol to obtain solution A;

[0049] S2: 40 mmol of 2-hydroxymethyl-1-methylimidazole (complexing agent) is ultrasonically dissolved in 80 mL of anhydrous methanol to obtain solution B;

[0050] S3: Solution A and B are quickly mixed, stirred at room temperature for 24 h, and after the reaction is completed, the precipitate is collected, washed, and dried to obtain the product;

[0051] S4: 1 g of the above product is first placed in a tube furnace for pretreatment at 400°C for 4 h, then 4 g of sulfur powder is added, and calcination treatment is carried out at 700°C for 4 h to obtain the bimetallic sulfur-oxygen compound.

[0052] Example 2

[0053] A preparation method of a bimetallic sulfur-oxygen compound, comprising the following steps:

[0054] S1: 2 mmol of potassium molybdate (molybdenum salt) and 1 mmol of zinc sulfate (zinc salt) are ultrasonically dissolved in 15 mL of anhydrous methanol to obtain solution A;

[0055] S2: 30 mmol of 1-methyl-2-chloromethylimidazole (complexing agent) was ultrasonically dissolved in 60 mL of anhydrous methanol to obtain solution B;

[0056] S3: Solution A and B were quickly mixed, stirred at room temperature for 24 h, and after the reaction was completed, the precipitate was collected, washed, and dried to obtain the product;

[0057] S4: 1 g of the above product was first placed in a tube furnace for pretreatment at 300°C for 3 h, then 3 g of sulfur powder was added, and calcination treatment was performed at 600°C for 3 h to obtain a double metal sulfide-oxide compound.

[0058] Example 3

[0059] A method for preparing a double metal sulfide-oxide compound, comprising the following steps:

[0060] S1: 1 mmol of sodium molybdate (molybdenum salt) and 1 mmol of zinc chloride (zinc salt) were ultrasonically dissolved in 10 mL of anhydrous methanol to obtain solution A;

[0061] S2: 20 mmol of 2-ethyl-4-methylimidazole (complexing agent) was ultrasonically dissolved in 40 mL of anhydrous methanol to obtain solution B;

[0062] S3: Solution A and B were quickly mixed, stirred at room temperature for 24 h, and after the reaction was completed, the precipitate was collected, washed, and dried to obtain the product;

[0063] S4: 1 g of the above product was first placed in a tube furnace for pretreatment at 200°C for 2 h, then 2 g of sulfur powder was added, and calcination treatment was performed at 500°C for 2 h to obtain a double metal sulfide-oxide compound.

[0064] Example 4

[0065] A method for preparing a double metal sulfide-oxide compound, comprising the following steps:

[0066] S1: 1 mmol of sodium molybdate (molybdenum salt) and 3 mmol of zinc nitrate (zinc salt) were ultrasonically dissolved in 20 mL of anhydrous methanol to obtain solution A;

[0067] S2: 25 mmol of 2-hydroxymethyl-1-methylimidazole (complexing agent) was ultrasonically dissolved in 50 mL of anhydrous methanol to obtain solution B;

[0068] S3: Solution A and B were quickly mixed, stirred at room temperature for 48 h, and after the reaction was completed, the precipitate was collected, washed, and dried to obtain the product;

[0069] S4: The above product g was first placed in a tube furnace at 350℃ for 2h pretreatment, then 3g of sulfur powder was added, and calcination treatment was carried out at 650℃ for 3h to obtain a double metal sulfide-oxide compound.

[0070] Example 5

[0071] A preparation method of a double metal sulfide-oxide compound, comprising the following steps:

[0072] S1: 2mmol of sodium molybdate (molybdenum salt) and 2mmol of zinc nitrate (zinc salt) were ultrasonically dissolved in 15mL of anhydrous methanol to obtain solution A;

[0073] S2: 20mmol of 1-methyl-2-chloromethyl imidazole (complexing agent) was ultrasonically dissolved in 15mL of anhydrous methanol to obtain solution B;

[0074] S3: Solution A and B were quickly mixed and stirred at room temperature for 24h, and after the reaction was completed, the precipitate was collected, washed and dried to obtain a product;

[0075] S4: The above product 1g was first placed in a tube furnace at 400℃ for 2h pretreatment, then 4g of sulfur powder was added, and calcination treatment was carried out at 550℃ for 3h to obtain a double metal sulfide-oxide compound.

[0076] Figure 1 The SEM image of the double metal sulfide-oxide compound prepared by the present application can be seen from the figure, and the double metal sulfide-oxide compound is composed of ultra-thin two-dimensional nanosheets vertically interwoven, and the thickness of the ultra-thin two-dimensional nanosheets is 15-20nm.

[0077] Figure 2 The XRD image of the double metal sulfide-oxide compound prepared by the present application can be seen from the figure, and the double metal sulfide-oxide compound is composed of MoS2, ZnS and MoO2.

[0078] Figure 3 The charge-discharge curve of the double metal sulfide-oxide compound prepared by the present application can be seen from the figure, and the prepared double metal sulfide-oxide compound has a first discharge specific capacity of 870mAh / g and a first coulombic efficiency of about 70% at a current density of 0.1A / g.

[0079] Table 1 is the electrochemical performance data of the double metal sulfide-oxide compound prepared by the present application and the products in patent numbers CN106115785A, CN112310385A and CN112599752A, and it can be seen that the composite electrode material prepared by the present application has advantages in comprehensive electrochemical performance such as discharge and charge specific capacity and first coulombic efficiency.

[0080] Table 1 Comparison of electrochemical performance of products prepared by the present application and related products

[0081]

[0082] The above merely illustrates the technical idea of the present application and cannot limit the protection scope of the present application. Any modification made according to the technical idea of the present application on the basis of the technical scheme falls within the protection scope of the present application.

Claims

1. A method for preparing a double metal sulfide-oxide compound, characterized by, The method comprises the following steps: a solution A is obtained by mixing a molybdenum salt, a zinc salt and a solvent; a solution B is obtained by mixing a complexing agent and a solvent; the solution A and the solution B are mixed and stirred at room temperature to react, and then the product is obtained by sequentially collecting the precipitate, cleaning and drying after the reaction is completed; a bimetallic sulfur-oxygen compound is obtained by mixing the product and sulfur powder and then performing calcination treatment; the molybdenum salt, the zinc salt and the solvent in the solution A are used in a ratio of (1-3) mmol:(1-3) mmol:(10-20) mL; the complexing agent is one of 2-ethyl-4-methylimidazole, 2-hydroxymethyl-1-methylimidazole and 1-methyl-2-chloromethylimidazole, and the solvent is anhydrous methanol; the complexing agent and the solvent in the solution B are used in a ratio of (20-40) mmol:(40-80) mL; the product is pretreated in a tube furnace before the product is mixed with sulfur powder and then calcination treatment is performed; the pretreatment temperature is 200-400 ℃, and the pretreatment time is 2-4 h; the mass ratio of the product to the sulfur powder is 1:(2-4); the calcination temperature is 500-700 ℃, and the calcination time is 2-4 h; the bimetallic sulfur-oxygen compound is composed of MoS2, ZnS and MoO2; the bimetallic sulfur-oxygen compound is composed of vertically interwoven ultrathin two-dimensional nanosheets, and the thickness of the ultrathin two-dimensional nanosheets is 15-20 nm.

2. The method of claim 1, wherein the metal oxide is selected from the group consisting of titanium oxide, vanadium oxide, chromium oxide, manganese oxide, iron oxide, cobalt oxide, nickel oxide, copper oxide, zinc oxide, and mixtures thereof. the molybdenum salt is one of ammonium molybdate, sodium molybdate and potassium molybdate; and the zinc salt is one of zinc nitrate, zinc sulfate and zinc chloride.

3. The method for preparing a bimetallic sulfur-oxygen compound according to claim 1, characterized in that, the stirring time is 24-48 h.

4. A double metal sulfide-oxide compound characterized in that, The bimetallic sulfur-oxygen compound is prepared by the preparation method in any one of claims 1-3, and is composed of vertically interwoven ultrathin two-dimensional nanosheets, and the thickness of the ultrathin two-dimensional nanosheets is 15-20 nm.

5. Application of the bimetallic sulfur-oxygen compound in claim 4 to an electrode material of a sodium ion battery.

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