Molybdenum disulfide material having large lattice spacing and preparation method therefor, negative electrode, and battery

Abstract

A molybdenum disulfide material having large lattice spacing and a preparation method therefor, a negative electrode, and a battery. The preparation method for a molybdenum disulfide material having large lattice spacing comprises: reacting a composite solution, in which a sulfur source, a molybdenum source and inducing metal ions are mixed, at a temperature maintained at 200-280°C, thereby obtaining a solid-liquid mixture after the reaction is finished; and separating out a solid substance in the solid-liquid mixture, thereby obtaining a molybdenum disulfide material having large lattice spacing, wherein the inducing metal ions are at least one of germanium ions, iron ions, gallium ions, nickel ions and manganese ions. The negative electrode material is prepared by using the preparation method. The negative electrode is prepared from the negative electrode material. The lithium-ion battery comprises the negative electrode. The molybdenum disulfide material having large lattice spacing prepared by using the preparation method has relatively large lattice spacing, and a battery assembled from a negative electrode prepared from same has relatively good electrochemical performance.

Description

High lattice spacing molybdenum disulfide material and preparation method thereof, negative electrode and battery

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This disclosure claims priority to Chinese patent application number 202311390766.0, filed with the State Intellectual Property Office of China on October 25, 2023, entitled “High lattice spacing molybdenum disulfide material, preparation method thereof, negative electrode and battery”, the entire contents of which are incorporated by reference into this disclosure. Technical Field

[0003] The present disclosure relates to the technical field of battery materials, and in particular to a high lattice spacing molybdenum disulfide material, a preparation method thereof, a negative electrode, and a battery. Background Art

[0004] Since the beginning of the 21st century, with the improvement of people's living standards and the development of the economy and society, the demand for clean energy has increased. The recent proliferation of portable electronic devices, along with their increasingly integrated and miniaturized development, has placed increasing demands on the performance of rechargeable lithium-ion batteries. Furthermore, lithium-ion batteries are widely used in a wide range of fields, including modern electronic digital devices, traditional automotive power systems, hybrid vehicles, and embedded micro-medical devices. Therefore, the advancement of advanced science and technology in modern society is highly dependent on energy storage, and research on high-performance lithium-ion batteries related to energy storage has attracted considerable attention.

[0005] For lithium-ion batteries, the negative electrode material is an important factor affecting the overall performance of the battery. Generally speaking, lithium-ion battery negative electrode materials with application potential must meet the following requirements: high specific capacity, good cycle stability and rate performance, and suitable reaction potential to avoid the formation of lithium dendrites. As a traditional commercial lithium battery negative electrode material, graphite has a relatively low specific capacity (372mAh g -1 ) hinders the further development of graphite materials in lithium-ion batteries.

[0006] In view of this, the present disclosure is proposed.

[0007] Summary of the Invention

[0008] The present invention aims to provide a high lattice spacing molybdenum disulfide material, a preparation method thereof, a negative electrode and a battery.

[0009] The present disclosure is achieved as follows:

[0010] In a first aspect, the present disclosure provides a method for preparing a high lattice spacing molybdenum disulfide material, comprising:

[0011] A composite solution containing a sulfur source, a molybdenum source and an inducing metal ion is allowed to react at a temperature of 230 to 270° C., and a solid-liquid mixture is obtained after the reaction is completed;

[0012] Separating the solid matter from the solid-liquid mixture to obtain a high lattice spacing molybdenum disulfide material;

[0013] The inducing metal ion is at least one of germanium ion, iron ion, gallium ion, nickel ion and manganese ion;

[0014] The molar ratio of the inducing metal ion to the molybdenum element is 1.0-2.0:1.0.

[0015] In an optional embodiment, the composite solution is kept warm for a reaction time of 10 to 12 hours.

[0016] In an optional embodiment, the sulfur source is selected from at least one of thiourea, acetylthiourea and thioacetamide.

[0017] In an optional embodiment, the molybdenum source is selected from at least one of ammonium molybdate tetrahydrate and sodium molybdate.

[0018] In an optional embodiment, the step of preparing a composite solution is further included before the heat preservation reaction. The preparation method of the composite solution includes:

[0019] uniformly mixing the molybdenum source and the inducing metal salt solution to obtain an intermediate mixed solution;

[0020] The sulfur source is added to the intermediate mixed solution and mixed thoroughly to obtain a composite solution.

[0021] In an optional embodiment, the temperature of the intermediate mixed solution is increased to 50-80° C. before adding the sulfur source to the intermediate mixed solution.

[0022] In an optional embodiment, the inducing metal salt solution is obtained by dissolving an inducing metal source in a hydrochloric acid solution, and the inducing metal source includes at least one of germanium dioxide, ferric chloride, gallium powder, nickel powder and manganese powder.

[0023] In an optional embodiment, the concentration of the hydrochloric acid solution is 0.5 to 1.5 mol / L.

[0024] In an optional embodiment, the ratio of the inducing metal source to the hydrochloric acid solution is 0.1-1.0 g:30 mL.

[0025] In an optional embodiment, the inducing metal salt solution is prepared by adding an inducing metal source to a hydrochloric acid solution and stirring for 2 to 5 hours.

[0026] In an optional embodiment, the molybdenum source and the inducing metal salt solution are mixed uniformly by:

[0027] Add the molybdenum source to the inducing metal salt solution at a temperature of 20 to 40° C. and stir for 3 to 5 hours.

[0028] In an optional embodiment, the method for separating solid matter from a solid-liquid mixture comprises:

[0029] The solid-liquid mixture is subjected to solid-liquid separation, and the solid matter is then dried.

[0030] In an optional embodiment, the method of solid-liquid separation is filtration or centrifugation.

[0031] In an optional embodiment, the drying temperature is 80-120° C., and the drying time is 10-14 hours.

[0032] In a second aspect, the present disclosure provides a high lattice spacing molybdenum disulfide material, which is prepared using the preparation method of any of the aforementioned embodiments.

[0033] In a third aspect, the present disclosure provides a negative electrode, which is made of the high lattice spacing molybdenum disulfide material as described in the above embodiment.

[0034] In a fourth aspect, the present disclosure provides a battery comprising the negative electrode according to the aforementioned embodiment.

[0035] The present disclosure has the following beneficial effects:

[0036] The preparation method provided by the present disclosure can induce metal ions to expand the lattice spacing of molybdenum disulfide in the reaction. By reacting sulfur, molybdenum and inducing metal ions at a temperature of 200-280°C through a hydrothermal reaction, a molybdenum disulfide material with a high lattice spacing can be generated. Compared with the method of preparing molybdenum sulfide negative electrode material by sintering, the lattice spacing of the product obtained by this method is larger and can reach greater than 0.8nm, or even exceed 0.9nm. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present disclosure and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0038] FIG1 is a low-magnification SEM image of the material obtained in Example 1;

[0039] FIG2 is a high-magnification SEM image of the material obtained in Example 1;

[0040] FIG3 is a low-magnification TEM image of the material obtained in Example 1;

[0041] FIG4 is a high-magnification TEM image of the material obtained in Example 1;

[0042] FIG5 is an XRD pattern of the material obtained in Example 1;

[0043] FIG6 is a charge-discharge cycle curve of the material prepared in Example 1 under low rate conditions;

[0044] FIG7 is a charge-discharge cycle curve of the negative electrode material prepared in Example 1 under high rate conditions. DETAILED DESCRIPTION

[0045] To make the purpose, technical solutions, and advantages of the embodiments of the present disclosure more clear, the technical solutions in the embodiments of the present disclosure are described clearly and completely below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer were followed. Reagents or instruments used where the manufacturer is not specified are conventional products that can be purchased commercially.

[0046] The features and performance of the present disclosure are further described in detail below with reference to the embodiments.

[0047] The present disclosure provides a method for preparing a high lattice spacing molybdenum disulfide material, comprising:

[0048] The composite solution containing the sulfur source, the molybdenum source and the inducing metal ions is subjected to a reaction at a temperature of 200 to 280° C. (e.g., 200° C., 230° C., 250° C. or 280° C.) to obtain a solid-liquid mixture after the reaction is completed;

[0049] Separating the solid matter from the solid-liquid mixture to obtain a high lattice spacing molybdenum disulfide material;

[0050] The inducing metal ion is at least one of germanium ion, iron ion, gallium ion, nickel ion and manganese ion;

[0051] The molar ratio of the inducing metal ion to the molybdenum element is 1.0 to 2.0:1.0 (for example, 1:1, 1.2:1, 1.5:1, 1.8:1 or 2:1).

[0052] The preparation method provided in the embodiment of the present disclosure plays a role in promoting phase change in the reaction by inducing metal ions. By reacting sulfur, molybdenum and inducing metal ions at a temperature of 200-280°C for 10-12 hours through a hydrothermal reaction, a molybdenum disulfide material with a high lattice spacing can be generated. Compared with the method of preparing manganese sulfide negative electrode materials by sintering, the lattice spacing of the product obtained by this method is larger and can reach greater than 0.8 or even exceed 0.9 nm.

[0053] The preparation method provided in the embodiment of the present disclosure provides a molybdenum sulfide negative electrode material having a flower-like structure, which can expand the contact area between the material and the electrolyte, allowing it to undergo more lithium insertion and removal reactions; this material can alleviate the volume change rate of lithium ions during the lithium insertion and removal process, reduce the pulverization of the material and the formation of solid-electrolyte interface (SEI) film, thereby reducing the loss of irreversible cycle capacity of lithium ions; the metallic properties exhibited by this high lattice spacing can greatly reduce the resistance during the lithium ion insertion and removal process, and can significantly increase the ion migration rate of the material, thereby improving the kinetic performance of the battery; this material can be applied to lithium-ion batteries to significantly improve the material's cycle performance and rate performance, and is extremely effective in fast charging applications.

[0054] Specifically, the preparation method is:

[0055] S1. Preparation of inducing metal salt solution

[0056] The inducing metal source is dissolved in the acid solution, and the solution is stirred thoroughly to obtain an inducing metal salt solution.

[0057] Optionally, the inducing metal source includes at least one of germanium dioxide, ferric chloride, gallium powder, nickel powder and manganese powder;

[0058] Optionally, the acid solution is preferably a hydrochloric acid solution, because the hydrochloric acid solution is relatively stable under high temperature hydrothermal conditions and does not produce other by-products, thereby affecting the final formation of the product; further, the concentration of the hydrochloric acid solution is 0.5-1.5 mol / L (e.g., 0.5 mol / L, 1 mol / L or 1.5 mol / L);

[0059] Optionally, when hydrochloric acid solution is selected as the acid solution for dissolving the inducing metal source, the feeding ratio of the inducing metal source and the hydrochloric acid solution is 0.1-1.0 g:30 mL (for example, 0.1 g / 30 mL, for example, 0.5 g / 30 mL or 1 g / 30 mL); further, the stirring time after the two are mixed is 2-5 h (for example, 2 h, 3 h or 5 h).

[0060] S2. Preparation of intermediate mixed solution

[0061] At 20-40° C. (eg, 20° C., 30° C., or 40° C.), a molybdenum source is added to the inducing metal salt solution, and the mixture is stirred and mixed thoroughly to obtain an intermediate mixed solution.

[0062] Optionally, the molybdenum source is selected from at least one of ammonium molybdate tetrahydrate and sodium molybdate.

[0063] Optionally, after the molybdenum source and the inducing metal salt solution are mixed, the stirring time is 3 to 5 hours (eg, 3 hours, 4 hours or 5 hours).

[0064] S3. Preparation of composite solution

[0065] Add the sulfur source to the intermediate mixed solution to fully dissolve the sulfur source and mix evenly.

[0066] Furthermore, in order to ensure that the sulfur source can be quickly dissolved and the two are mixed with each other, the specific method of this step is: raising the temperature of the intermediate mixed solution to 50-80°C (for example, 50°C, 60°C, 70°C or 80°C), adding the sulfur source thereto after heating, and keeping the temperature and stirring continuously for 3-5h (for example, 3h, 4h or 5h) to obtain a composite solution.

[0067] Optionally, the sulfur source is selected from at least one of thiourea, acetylthiourea and thioacetamide.

[0068] The feeding amount of the sulfur source and the molybdenum source can be determined according to the stoichiometric ratio of the reaction to generate manganese sulfide. Either of them can be excessive, and the target product can be obtained in excess. The disadvantage is that there may be a waste of raw materials.

[0069] S4. Hydrothermal reaction

[0070] The composite solution is placed in a reactor, the temperature of the reactor is controlled to be 200-280° C. (for example, 230° C., 240° C., 250° C., 260° C. or 270° C.), and the reaction is carried out at this temperature for 10-12 hours (for example, 10 hours, 11 hours or 12 hours). After the reaction is completed, a solid-liquid mixture is obtained.

[0071] S5. Obtain finished product

[0072] After the solid-liquid mixture obtained in the previous step is cooled, the solid matter in the solid-liquid mixture is separated therefrom to obtain a high lattice spacing molybdenum disulfide material.

[0073] Specifically, the method for separating solid matter from a solid-liquid mixture includes: performing solid-liquid separation on the solid-liquid mixture, and then drying the solid matter.

[0074] Optionally, the solid-liquid separation method is filtration or centrifugation;

[0075] Optionally, the drying temperature is 80-120° C. (eg, 80° C., 100° C., or 120° C.), and the drying time is 10-14 h (eg, 10 h, 12 h, or 14 h).

[0076] The embodiments of the present disclosure also provide a high lattice spacing molybdenum disulfide material, which is prepared using the preparation method provided in the embodiments of the present disclosure.

[0077] An embodiment of the present disclosure also provides a negative electrode, which is made using the high lattice spacing molybdenum disulfide material provided by the present disclosure.

[0078] The embodiments of the present disclosure also provide a lithium-ion battery, comprising the negative electrode provided by the embodiments of the present disclosure.

[0079] Example 1

[0080] (a): 0.126g of ferric chloride (0.001mol Fe) was placed in 30mL of 1mol / L -1 Dissolve in aqueous hydrochloric acid solution and stir for 4 hours to obtain an inducing metal salt solution;

[0081] (b) At 40° C., 0.185 g of ammonium molybdate tetrahydrate (0.00105 mol Mo) was added to the inducing metal salt solution and stirred for 4 hours to obtain an intermediate mixed solution.

[0082] (c) The temperature of the intermediate mixed solution was raised to 70°C, 2 g of thiourea (0.026 mol S) was added thereto, and stirring was continued for 4 hours to obtain a composite solution;

[0083] (d) placing the composite solution into a reactor and maintaining the temperature at 250° C. for 10 hours for hydrothermal reaction, and obtaining a solid-liquid mixture after the reaction is completed;

[0084] (e): After cooling, the obtained solid-liquid mixture is filtered, and the filtered solid is placed in an oven at 100° C. and dried for 12 hours to obtain a high lattice spacing molybdenum disulfide material.

[0085] Example 2

[0086] This embodiment is substantially the same as embodiment 1, except that 0.126 g of ferric chloride is replaced with 0.104 g of germanium dioxide.

[0087] Example 3

[0088] This embodiment is substantially the same as embodiment 1, except that 0.126 g of ferric chloride is replaced with 0.069 g of gallium powder.

[0089] Example 4

[0090] This embodiment is substantially the same as embodiment 1, except that 0.126 g of ferric chloride is replaced with 0.197 g of nickel powder.

[0091] Example 5

[0092] This embodiment is substantially the same as embodiment 1, except that 0.126 g of ferric chloride is replaced with 0.055 g of manganese powder.

[0093] Example 6

[0094] This embodiment is substantially the same as embodiment 1, except that ammonium molybdate tetrahydrate is replaced by sodium molybdate in an equal molar amount of the molybdenum element; and thiourea is replaced by thioacetamide in an equal molar amount of the sulfur element.

[0095] Example 7

[0096] This embodiment is basically the same as embodiment 1, except that the hydrothermal reaction temperature is 200°C.

[0097] Example 8

[0098] This embodiment is basically the same as embodiment 1, except that the hydrothermal reaction temperature is 280°C.

[0099] Example 9

[0100] This embodiment is substantially the same as embodiment 1, except that the amount of ferric chloride added is 0.063 g, i.e., 0.0015 mol Fe.

[0101] Example 10

[0102] This embodiment is substantially the same as embodiment 1, except that the amount of ferric chloride added is 0.252 g, i.e., 0.002 mol Fe.

[0103] Comparative Example 1

[0104] This comparative example is basically the same as Example 1, except that the hydrothermal reaction temperature is 180°C.

[0105] Comparative Example 2

[0106] This comparative example is basically the same as Example 1, except that the hydrothermal reaction temperature is 300°C.

[0107] Comparative Example 3

[0108] This comparative example is substantially the same as Example 1, except that the amount of ferric chloride added is 0.0063 g, i.e., 0.0001 mol Fe.

[0109] Comparative Example 4

[0110] This comparative example is substantially the same as Example 1, except that the amount of ferric chloride added is 0.378 g, i.e., 0.003 mol Fe.

[0111] Comparative Example 5

[0112] The amount of molybdenum, sulfur and inducing metal ions used in this comparative example is the same as that in Example 1, except that the preparation method is different. Specifically:

[0113] (1) Add 0.273 g of MoCl5, 2.0 g of thiourea, and 0.162 g of anhydrous FeCl3 to 50 mL of ethanol and stir to mix well to obtain solution A;

[0114] (2) Solution A was magnetically stirred in air for 2 days to obtain a uniform brown gel;

[0115] (3) The brown gel and the flask were transferred to a vacuum drying oven and dried continuously at 100°C for 2 h to form a brown powder.

[0116] (4) The powder obtained in step (3) was then scraped out and ground, and then transferred into a tube furnace for high-temperature sintering under an Ar inert atmosphere at a temperature of 600° C. for 3 h to prepare a transition metal-doped sodium molybdenum disulfide battery negative electrode material.

[0117] Comparative Example 6

[0118] This comparative example provides an artificial graphite particle negative electrode material.

[0119] Experimental Example 1

[0120] The lattice spacing of Examples 1 to 10 and Comparative Examples 1 to 5 was measured. The lattice spacing of the above examples and comparative examples is recorded in Table 1. The test method is high-magnification transmission electron microscopy measurement.

[0121] Table 1 Statistics of lattice spacing of various embodiments and comparative examples

[0122] It can be seen from the above table that the high lattice spacing molybdenum disulfide materials prepared in various embodiments of the present application have a large lattice spacing, and the spacing values ​​are all above 0.8 nm.

[0123] Comparing Comparative Examples 1 and 2 with Examples 7 and 8, it can be seen that the negative electrode materials prepared in Comparative Examples 1 and 2 have a smaller lattice spacing, and the hydrothermal reaction temperatures of Comparative Examples 1 and 2 are not within the range required by this application. Therefore, if the hydrothermal reaction temperature is not within the range required by this application, the lattice spacing of the obtained molybdenum sulfide negative electrode material is not large enough;

[0124] Comparing Comparative Examples 3 and 4 with Examples 9 and 10, it can be seen that the negative electrode materials prepared in Comparative Examples 3 and 4 have a smaller lattice spacing, and the inducing metal ions added in Comparative Examples 3 and 4 are not within the range required by this application. It can be seen that if the amount of inducing metal ions is not within the range required by this application, the lattice spacing of the obtained molybdenum sulfide negative electrode material is not large enough;

[0125] Comparing Example 1 with Comparative Example 5, the lattice spacing of the material prepared in Example 1 is significantly larger than that in Comparative Example 5, which shows that the hydrothermal reaction provided by the present disclosure for preparing the molybdenum sulfide negative electrode material can produce a negative electrode material with a larger lattice spacing compared to the existing method of preparing the gel and then sintering.

[0126] Experimental Example 2

[0127] The SEM images of Example 1 were taken as shown in Figures 1-2.

[0128] Figures 1 and 2 are low-rate SEM and high-rate SEM images of the negative electrode material prepared in Example 1, respectively. It can be seen from the figures that the prepared negative electrode material has a flower-like structure. The nanoflower structure can improve the permeability of the electrolyte in the electrode material, improve the contact between the electrode and the electrolyte, and thus improve the reaction activity of the electrode and the charge and discharge efficiency of the battery. It can also buffer the volume change caused by the insertion and removal of lithium ions to a certain extent, reduce internal stress, and is expected to improve the cycle stability of the material and prevent the peeling of the active material.

[0129] Figures 3 and 4 are low-rate TEM and high-rate TEM images of the negative electrode material obtained in Example 1, respectively. It can be seen from the figures that the obtained negative electrode material has a flower-like structure, and it can be seen that the lattice spacing of the obtained negative electrode material can reach 0.9 nm. A larger lattice spacing usually means that the path for lithium ions to migrate in the lattice is wider, which may reduce the resistance during the migration of lithium ions and improve the migration performance of lithium ions. A larger lattice spacing can also better accommodate the insertion / extraction of lithium ions, which may reduce the volume expansion and contraction caused by the entry and exit of lithium ions into and out of the lattice, thereby improving the structural stability and cycle stability of the electrode material. Under certain circumstances, a larger lattice spacing may reduce the energy barrier for the migration of lithium ions in the lattice, reduce energy loss and polarization during the charge and discharge process, and thus improve the energy efficiency of the battery.

[0130] FIG5 is an XRD pattern of the negative electrode material prepared in Example 1. Due to the leftward shift of the molybdenum sulfide (002) crystal plane, according to the Bragg equation 2dsin(θ)=λ, it can be calculated that the interlayer spacing of the negative electrode material prepared in Example 1 is 0.9 nm, which further confirms the results of the TEM test.

[0131] Figure 6 shows the low rate (0.1 A g) of the negative electrode material prepared in Example 1. -1 ) under the conditions of charge and discharge cycle curve, it can be seen that after 200 cycles, the reversible charge and discharge capacity can reach 1800mAh g -1 .

[0132] FIG7 is a high rate (50A g) graph of the negative electrode material prepared in Example 1. -1 ) under the conditions of charge and discharge cycle curve, it can be seen that after 10,000 cycles, the reversible charge and discharge capacity can reach 200 mAh g -1 .

[0133] Experimental Example 3

[0134] Using metallic lithium as the counter electrode, the negative electrode materials prepared or provided in the above embodiments and comparative examples were respectively made into half-cells. The preparation of the negative electrode sheet was as follows: the negative electrode material, polyvinylidene fluoride, and acetylene black were mixed uniformly in a mass ratio of 8:1:1 to form an electrode slurry, which was then coated on a copper foil current collector and dried using a pressure of 2MPa / cm 2 Press and cut with pressure.

[0135] The electrochemical performance of the half-cells prepared in each example and comparative example was tested using a constant current charge-discharge test. The test results are recorded in Table 2.

[0136] Table 2 Electrochemical properties of batteries prepared in various embodiments and comparative examples

[0137] It can be seen from the above table that the high lattice spacing molybdenum disulfide materials prepared in various embodiments of the present disclosure all have good electrochemical properties.

[0138] Comparing Comparative Examples 1 and 2 with Examples 7 and 8, it can be seen that the electrochemical performance of the batteries assembled with the negative electrode materials prepared in Comparative Examples 1 and 2 is poor. This shows that if the hydrothermal reaction temperature is not within the range required by this application, the electrochemical performance of the obtained molybdenum sulfide negative electrode material is not good enough;

[0139] Comparing Comparative Examples 3 and 4 with Examples 9 and 10, it can be seen that the electrochemical performance of the batteries assembled with the negative electrode materials prepared in Comparative Examples 3 and 4 is poor. This shows that if the amount of inducing metal ions is not within the range required by this application, the electrochemical performance of the obtained molybdenum sulfide negative electrode material is not good enough;

[0140] Comparing Example 1 with Comparative Example 5, the electrochemical properties of the battery assembled from the material prepared in Example 1 are significantly better than those of Comparative Example 5, which indicates that the molybdenum sulfide negative electrode material prepared by the hydrothermal reaction provided by the present disclosure has better electrochemical performance than the negative electrode material prepared by the existing method of preparing the gel and then sintering.

[0141] Comparing Example 1 with Comparative Example 6, the battery assembled with the negative electrode material prepared in Example 1 has significantly better electrochemical performance, indicating that the high lattice spacing molybdenum disulfide material prepared in the present disclosure has better performance than artificial graphite.

[0142] In summary, the preparation method provided in the embodiment of the present disclosure reacts sulfur, molybdenum and inducing metal ions at a temperature of 200-280°C for 10-12 hours through a hydrothermal reaction, which can generate a molybdenum disulfide material with a high lattice spacing, and the lattice spacing can reach greater than 0.8nm, or even exceed 0.9nm.

[0143] The molybdenum sulfide negative electrode material prepared by this preparation method has the following advantages:

[0144] 1. It has a flower-like structure, which can expand the contact area between the material and the electrolyte, allowing it to undergo more lithium insertion reactions;

[0145] 2. The nanoflower-like structure can improve the penetration of the electrolyte into the electrode material, enhance the contact between the electrode and the electrolyte, and thus increase the reaction activity of the electrode and improve the charge and discharge efficiency of the battery;

[0146] 3. This material can alleviate the volume change rate of lithium ions during the process of lithium insertion and extraction, reduce the pulverization of the material and the formation of solid-electrolyte interface (SEI) film, thereby reducing the loss of irreversible cycle capacity of lithium ions;

[0147] 4. The metallic properties exhibited by this high lattice spacing can greatly reduce the resistance during lithium ion insertion and extraction, and can significantly increase the ion migration rate of the material and improve the kinetic performance of the battery;

[0148] 5. Under certain circumstances, a larger lattice spacing may reduce the energy barrier for lithium ion migration in the lattice, reduce energy loss and polarization during charging and discharging, and thus improve the energy efficiency of the battery;

[0149] 6. This material can be used in lithium-ion batteries to significantly improve its cycle performance and rate performance, and is extremely effective in fast charging applications.

[0150] The above are merely preferred embodiments of the present disclosure and are not intended to limit the present disclosure. Those skilled in the art will readily appreciate that various modifications and variations of the present disclosure are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present disclosure shall be included within the scope of protection of the present disclosure. Industrial Applicability

[0151] The present disclosure provides a high-lattice-spacing molybdenum disulfide material, a preparation method thereof, a negative electrode, and a battery. The disclosed preparation method for the high-lattice-spacing molybdenum disulfide material comprises: subjecting a composite solution containing a sulfur source, a molybdenum source, and an inducing metal ion to a reaction at a temperature of 200 to 280°C, obtaining a solid-liquid mixture after the reaction; separating the solid matter from the solid-liquid mixture to obtain the high-lattice-spacing molybdenum disulfide material; the inducing metal ion is at least one of germanium ions, iron ions, gallium ions, nickel ions, and manganese ions. The disclosed negative electrode material is prepared using the above-mentioned preparation method. The disclosed negative electrode is prepared using the above-mentioned negative electrode material. The disclosed lithium-ion battery includes the above-mentioned negative electrode. The high-lattice-spacing molybdenum disulfide material prepared by the preparation method provided in the present disclosure has a large lattice spacing, and when made into a negative electrode and assembled into a battery, it has excellent electrochemical performance.

[0152] Furthermore, it is understood that the high lattice spacing molybdenum disulfide materials, preparation methods, negative electrodes, and batteries disclosed herein are reproducible and can be used in a variety of industrial applications. For example, the high lattice spacing molybdenum disulfide materials, preparation methods, negative electrodes, and batteries disclosed herein can be used in the field of battery materials technology.

Claims

1. A method for preparing a high lattice spacing molybdenum disulfide material, characterized in that: include: A composite solution containing a sulfur source, a molybdenum source and an inducing metal ion is subjected to a reaction at a temperature of 200 to 280° C., and a solid-liquid mixture is obtained after the reaction is completed. Separating the solid matter from the solid-liquid mixture to obtain a high lattice spacing molybdenum disulfide material; The inducing metal ion is at least one of germanium ion, iron ion, gallium ion, nickel ion and manganese ion; The molar ratio of the inducing metal ion to the molybdenum element is 1.0-2.0:1.

0.

2. The preparation method according to claim 1, characterized in that: Also includes at least one of the following features (1) to (3); (1) The sulfur source is selected from at least one of thiourea, acetylthiourea and thioacetamide; (2) The molybdenum source is selected from at least one of ammonium molybdate tetrahydrate and sodium molybdate; (3) The composite solution is kept warm for a reaction time of 10 to 12 hours.

3. The preparation method according to claim 1, characterized in that: Before the heat preservation reaction, the composite solution is prepared. The preparation method of the composite solution includes: The molybdenum source and the inducing metal salt solution are uniformly mixed to obtain an intermediate mixed solution; The temperature of the intermediate mixed solution is raised to 50-80° C., and a sulfur source is added to the intermediate mixed solution and mixed thoroughly to obtain the composite solution.

4. The preparation method according to claim 3, characterized in that: The inducing metal salt solution is obtained by dissolving an inducing metal source in a hydrochloric acid solution, and the inducing metal source includes at least one of germanium dioxide, ferric chloride, gallium powder, nickel powder and manganese powder.

5. The preparation method according to claim 4, characterized in that: Also includes at least one of the following features (1) to (4); (1) The concentration of the hydrochloric acid solution is 0.5 to 1.5 mol / L; (2) The ratio of the inducing metal source to the hydrochloric acid solution is 1.0-2.0 g:20 mL; (3) The preparation method of the inducing metal salt solution is: adding the inducing metal source to the hydrochloric acid solution and stirring for 2 to 5 hours; (4) The molybdenum source and the inducing metal salt solution are mixed uniformly by adding the molybdenum source to the inducing metal salt solution at a temperature of 20 to 40° C. and stirring for 3 to 5 hours.

6. The preparation method according to claim 1, characterized in that: The method for separating the solid matter in the solid-liquid mixture comprises: The solid-liquid mixture is subjected to solid-liquid separation, and then the solid matter is dried.

7. The preparation method according to claim 6, characterized in that: Also includes at least one of the following features (1) and (2); (1) The method of solid-liquid separation is filtration or centrifugation; (2) Drying temperature is 80-120°C and time is 10-14 hours.

8. A high lattice spacing molybdenum disulfide material, characterized in that: The method is as described in any one of claims 1 to 7.

9. A negative electrode, characterized in that It is made from the high lattice spacing molybdenum disulfide material as claimed in claim 8.

10. A lithium ion battery, characterized in that: Comprising the negative electrode as claimed in claim 9.

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