A high-performance layered SiO based on interlayer embedding method x Its preparation methods and applications

Abstract

A high-performance layered SiO based on interlayer embedding method x This invention relates to the field of lithium-ion battery anode materials, including their preparation methods and applications. The objective of this invention is to provide a high-performance layered SiO₂ based on an interlayer embedding method. x Its preparation method and applications are also described. The method employs interlayer intercalation to embed small organic molecules between layers of siloxane. By adjusting the type and content of the intercalated substances, the layered SiO₂ structure can be controlled. x The purpose of this invention is to reduce the oxygen content in the material, suppress interlayer grain growth, and prevent heteroatom doping through in-situ carbon layer formation. The layered SiO₂ provided by this invention... x The material exhibits excellent electrochemical properties and demonstrates high battery specific capacity when used as a negative electrode in lithium-ion batteries.

Description

Technical Field

[0001] This invention belongs to the field of lithium-ion battery anode materials, specifically relating to a high-performance layered SiO based on interlayer embedding method. x Its preparation methods and applications. Background Technology

[0002] As energy storage devices, lithium-ion batteries play a decisive role in the development of key industries such as electric vehicles, consumer electronics, and energy storage systems. The performance of the anode material, a core component of lithium-ion batteries, directly affects the overall performance of the battery. While the widely used graphite anode material boasts mature technology and low cost, its energy density is nearing its theoretical limit, making it difficult to meet the market's growing demand for high-energy-density batteries.

[0003] In stark contrast, silicon anode materials have become a popular choice for next-generation lithium-ion battery anode materials due to their significant advantages, including high theoretical specific capacity (up to 4200 mAh / g), low lithium deintercalation potential, and environmental friendliness. However, silicon-based materials undergo significant volume changes during the lithium insertion / extraction process in lithium-ion batteries. This drastic expansion effect leads to rapid capacity decay, severely limiting the widespread application of silicon-based materials in industrial fields.

[0004] Layered SiO x The material stands out due to its unique structural design, effectively mitigating the volume expansion problem of silicon during cycling and ensuring the battery maintains good cycle performance. However, the role of SiO₂ cannot be ignored. x Excessively high oxygen content in SiO₂ can negatively impact its lithium storage capacity. Therefore, how to precisely control the oxygen content of layered SiO₂ is crucial. x The oxygen content in materials has become a key issue driving their practical application. Meanwhile, elemental doping can effectively improve the electrochemical properties of materials, such as conductivity. How to perform efficient and controllable elemental doping is of great significance for improving the performance of lithium-ion batteries. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide a high-performance layered SiO based on the interlayer embedding method. x Its preparation method and applications are also described. The method employs interlayer intercalation to embed small organic molecules between layers of siloxane. By adjusting the type and content of the intercalated substances, the layered SiO₂ structure can be controlled. x The purpose of this invention is to reduce the oxygen content in the material, suppress interlayer grain growth, and prevent heteroatom doping through in-situ carbon layer formation. The layered SiO₂ provided by this invention... x The material exhibits excellent electrochemical properties and demonstrates high battery specific capacity when used as a negative electrode in lithium-ion batteries.

[0006] The technical solution of the present invention is as follows:

[0007] One of the objectives of this invention is to provide a high-performance layered SiO2 based on the interlayer embedding method. x The preparation method of [the substance] is carried out according to the following steps:

[0008] S1: Disperse the layered siloxane material in a solvent, then add organic small molecule material, sonicate, and then hydrothermally react under inert gas protection. After the reaction is completed, separate the solid and liquid phases, wash and dry to obtain the siloxane material with interlayer embedded organic small molecules.

[0009] S2: Heat-treating the interlayered siloxane material with intercalated organic small molecules in an inert gas to obtain high-performance layered SiO2. x .

[0010] Further specifying, the high-performance layered SiO based on the interlayer embedding method of the present invention x Preparation method: Preparation of layered siloxane material in S1: Mix concentrated acid and silicon metal compound and stir for a period of time, then filter, wash and dry to obtain layered siloxane material.

[0011] To further specify, the preparation of layered silicate materials involves using one or more of the following concentrated acids: hydrofluoric acid, nitric acid, sulfuric acid, sulfurous acid, hydrochloric acid, phosphoric acid, boric acid, oxalic acid, lactic acid, acetic acid, and citric acid.

[0012] Furthermore, the preparation of layered silicate materials is specified as follows: the concentration of concentrated acid is 0.1–25 mol / L.

[0013] Further specifying the preparation of layered siloxane materials: the silicon metal compound is one or more of the following: vanadium silicide, calcium silicide, titanium silicide, cobalt silicide, tantalum silicide, iron silicide, cerium silicide, niobium silicide, copper silicide, hafnium silicide, zirconium silicide, nickel silicide, tungsten silicide, molybdenum silicide, tantalum silicide, chromium silicide, manganese silicide, lithium silicide, and sodium silicide.

[0014] To further specify, the preparation of layered siloxane materials is as follows: the ratio of silicon metal compound to concentrated acid is 1g:(10~100)mL.

[0015] To further specify, the preparation of layered silicate materials involves stirring for 0.5–24 hours.

[0016] Further specifying, the high-performance layered SiO based on the interlayer embedding method of the present invention x Preparation method: The solvent in S1 is one or more of water, methanol, ethanol, diethyl ether, ethyl acetate, ethylene glycol, isopropanol, N,N-dimethylformamide, dimethyl sulfoxide, tetrahydrofuran, acetonitrile, acetone, dichloromethane, and N-methylpyrrolidone.

[0017] Further specifying, the high-performance layered SiO based on the interlayer embedding method of the present invention x Preparation method: The organic small molecules in S1 are one or more of urea, melamine, thiourea, dopamine, aniline, ethylenediamine, arginine, glutamine, cysteine, thiophene, pyrrole, thiazole, imidazole, pyridine, pyrazole, and carbazole.

[0018] Further specifying, the high-performance layered SiO based on the interlayer embedding method of the present invention x Preparation method: The ratio of layered siloxane material to solvent in S1 is 1g:(10~200)mL.

[0019] Further specifying, the high-performance layered SiO based on the interlayer embedding method of the present invention x Preparation method: The mass ratio of layered siloxane material to organic small molecule material in S1 is 1:(0.1~10).

[0020] Further specifying, the high-performance layered SiO based on the interlayer embedding method of the present invention x Preparation method: The ultrasonic treatment time in S1 is 0.5 to 24 hours.

[0021] Further specifying, the high-performance layered SiO based on the interlayer embedding method of the present invention x Preparation method: The hydrothermal reaction temperature in S1 is 40-100℃, and the time is 0.5-24h.

[0022] Further specifying, the high-performance layered SiO based on the interlayer embedding method of the present invention x Preparation method: The inert gas in S1 is argon or nitrogen.

[0023] Further specifying, the high-performance layered SiO based on the interlayer embedding method of the present invention x Preparation method: The inert gas in S2 is argon or nitrogen.

[0024] Further specifying, the high-performance layered SiO based on the interlayer embedding method of the present invention x Preparation method: The heat treatment temperature in S2 is 150-1000℃, and the time is 0.5-24h.

[0025] The second objective of this invention is to provide a high-performance layered SiO2 prepared by the above method. x .

[0026] The third objective of this invention is to provide a high-performance layered SiO2 prepared by the above method. x It is used as an active material for the negative electrode of batteries.

[0027] The fourth objective of this invention is to provide a negative electrode sheet, wherein the negative electrode sheet is composed of the aforementioned high-performance layered SiO₂.x It is prepared from binders and conductive agents.

[0028] The fifth objective of this invention is to provide an application of the above-mentioned negative electrode sheet in a lithium-ion battery.

[0029] The advantages of this invention compared to existing technologies are:

[0030] (1) This invention uses an interlayer embedding method to embed small organic molecules into the interlayer of siloxane. Through a high-temperature heat treatment process, the reaction between the interlayer organic molecules and the oxygen-containing functional groups in the siloxane framework is triggered, thereby achieving directional control of the intrinsic oxygen content of the material. In this process, the in-situ generated nano-carbon layer effectively inhibits the growth of interlayer grains. The synchronously introduced heteroatom doping can significantly improve the conductivity of the material.

[0031] (2) This invention can quantitatively regulate the layered SiO₂ structure by controlling the embedding ratio of small organic molecules. x Oxygen content of the material.

[0032] (3) This invention can achieve layered SiO2 by controlling the types of small organic molecules. x Multi-element controllable doping of materials.

[0033] (4) High-performance layered SiO2 prepared by the present invention x Materials have made significant progress in improving the electrochemical performance of lithium-ion batteries. Attached Figure Description

[0034] Figure 1 The high-performance layered SiO2 prepared in Example 1 x SEM images of the material;

[0035] Figure 2 The high-performance layered SiO2 prepared in Example 1 x XPS plot of the material;

[0036] Figure 3 The high-performance layered SiO2 prepared in Example 1 x The initial charge-discharge curve of the material;

[0037] Figure 4 The high-performance layered SiO2 prepared in Example 2 x Cyclic performance of the material at a current density of 0.5 A / g;

[0038] Figure 5 The high-performance layered SiO2 prepared in Example 3 x Cyclic performance of the material at a current density of 0.5 A / g. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0040] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, the materials, reagents, methods, and instruments used are all conventional materials, reagents, methods, and instruments in the art, and can be obtained commercially by those skilled in the art.

[0041] The terms “comprising,” “including,” “having,” “containing,” or any other variations thereof, as used in the following embodiments, are intended to cover a non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that includes the listed elements is not necessarily limited to those elements, but may include other elements not expressly listed or elements inherent to such a composition, step, method, article, or apparatus.

[0042] When a quantity, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pair of any upper or preferred value with any lower or preferred value, regardless of whether the range is disclosed individually. For example, when the range “1 to 5” is disclosed, the described range should be interpreted as including ranges “1 to 4”, “1 to 3”, “1 to 2”, “1 to 2 and 4 to 5”, “1 to 3 and 5”, etc. When numerical ranges are described herein, unless otherwise stated, the range is intended to include its endpoints and all integers and fractions within that range. In this specification and claims, range definitions may be combined and / or interchanged, unless otherwise stated, these ranges include all subranges contained therein.

[0043] The indefinite articles “a” and “an” preceding an element or component of this invention do not impose any limitation on the quantity (i.e., number of times) of the element or component. Therefore, “an” or “a” should be interpreted as including one or at least one, and the singular form of an element or component also includes the plural form, unless the quantity clearly refers only to the singular form.

[0044] In this invention, "an embodiment" or "embodiment" refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that excludes other embodiments.

[0045] The endpoints and any values ​​of the ranges disclosed in this invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0046] Example 1

[0047] This embodiment provides a method for preparing high-performance layered SiO2 using interlayer embedding. x The method for using materials includes the following steps:

[0048] (1) Add 10g of iron silicide to 100mL of sulfuric acid with a concentration of 2mol / L, mix evenly, stir and react for 12h, wash 3 times with deionized water, and vacuum dry at 80℃ for 10h to obtain layered siloxane material.

[0049] (2) Add 0.5g of the layered siloxane material obtained in step (1) to 20mL of N,N-dimethylformamide, disperse evenly, then add 0.5g of thiophene and sonicate for 3h. Then transfer to a high-pressure reactor, purge with nitrogen to remove air. After sealing, heat to 100℃ and keep warm for 5h, wash three times with deionized water, and vacuum dry at 80℃ for 10h to obtain siloxane material with interlayer embedded organic small molecules;

[0050] (3) The interlayer embedded organic small molecules of siloxene material obtained in step (2) are placed in a tube furnace, heated to 600°C at a heating rate of 5°C / min under an argon atmosphere, and kept at a constant temperature for 3 hours. After natural cooling to room temperature, high-performance layered SiOx material can be obtained.

[0051] SEM images of the high-performance layered SiOx material obtained in Example 1 are shown below. Figure 1 As shown in the figure, this SiO x The material consists of micron-sized particles with a layered stacked structure, and there are a large number of voids between the layers.

[0052] The XPS spectrum of Si 2p in the high-performance layered SiOx material obtained in Example 1 is shown below. Figure 2 As shown, the peak fitting results indicate that it is composed of Si 0 Si + and Si 4+ Composition, SiO2 was calculated based on peak area ratio. x The value of x in the equation is 1.29.

[0053] The electrochemical performance of the silicon-based composite anode material obtained by testing coin cells was compared with that of the layered SiO2 prepared in Example 1. xThe material is an active substance, with PAA as a binder and conductive agent Super P added in a mass ratio of active substance:PAA:super P = 8:1:1. The mixture is then thoroughly stirred to form a negative electrode slurry. This slurry is then evenly coated onto copper foil, placed in an oven at 80℃ for 10 hours, and finally rolled and pressed to obtain the negative electrode sheet.

[0054] The prepared negative electrode sheet was used as the negative electrode of the lithium-ion battery. The positive electrode material was lithium metal. The separator was a polypropylene microporous membrane. The electrolyte was a 1 mol / L LiPF6 EC+DEC (volume ratio 1:1) solution. The coin cell was assembled in a glove box filled with argon atmosphere and the coin cell was subjected to charge-discharge cycle test.

[0055] The battery was first activated for 3 cycles at a current density of 0.1 A / g, and then subsequent tests were conducted at a current density of 0.5 A / g.

[0056] The electrochemical test showed that the charging cutoff voltage was 1.50V and the discharging cutoff voltage was 0.01V.

[0057] Example 2

[0058] This embodiment provides a method for preparing high-performance layered SiO2 using interlayer embedding. x The method for using materials includes the following steps:

[0059] (1) Add 2g of nickel silicide to 100mL of 10mol / L nitric acid, mix evenly, stir and react for 24h, wash 3 times with deionized water, and dry under vacuum at 80℃ for 10h to obtain layered siloxane material.

[0060] (2) Add 1g of the layered siloxane material obtained in step (1) to 20mL of water, disperse evenly, add 0.2g of cysteine, and sonicate for 2h. Then transfer to a high-pressure reactor, purge with nitrogen to remove air. After sealing, heat to 80℃ and keep warm for 1h, wash 3 times with deionized water, and vacuum dry at 80℃ for 10h to obtain siloxane material with interlayer embedded organic small molecules;

[0061] (3) The interlayered organic small molecule-embedded siloxane material obtained in step (2) is placed in a tube furnace and heated to 450°C at a heating rate of 5°C / min under an argon atmosphere, and held at that temperature for 1 hour. After naturally cooling to room temperature, high-performance layered SiO2 can be obtained. x .

[0062] The prepared layered SiO x The materials were used to fabricate the negative electrode material for lithium-ion batteries, and the batteries were then subjected to charge and discharge tests.

[0063] Other areas not mentioned are the same as in Example 1.

[0064] Example 3

[0065] This embodiment provides a method for preparing high-performance layered SiO2 using interlayer embedding. x The method for using materials includes the following steps:

[0066] (1) Add 2g of calcium silicide to 100mL of 10mol / L hydrochloric acid, mix evenly, stir and react for 12h, wash 3 times with deionized water, and vacuum dry at 80℃ for 10h to obtain layered siloxane material.

[0067] (2) Add 1g of the layered siloxane material obtained in step (1) to 50mL of isopropanol, disperse evenly, then add 0.5g of aniline and sonicate for 5h. Then transfer to a high-pressure reactor, purge with argon gas to remove air. After sealing, heat to 80℃ and keep warm for 12h, wash three times with deionized water, and vacuum dry at 80℃ for 10h to obtain siloxane material with interlayer embedded organic small molecules;

[0068] (3) The interlayered organic small molecule-embedded siloxane material obtained in step (2) is placed in a tube furnace and heated to 500°C at a heating rate of 5°C / min under a nitrogen atmosphere, and held at that temperature for 1 hour. After naturally cooling to room temperature, high-performance layered SiO2 can be obtained. x .

[0069] The prepared layered SiO x The materials were used to fabricate the negative electrode material for lithium-ion batteries, and the batteries were then subjected to charge and discharge tests.

[0070] Other areas not mentioned are the same as in Example 1.

[0071] Comparative Example 1

[0072] This comparative example provides a method for preparing layered SiOx material, including the following steps:

[0073] (1) Add 1g of calcium silicide to 50mL of 12mol / L hydrochloric acid, mix evenly, stir and react for 10h, wash 3 times with deionized water, and vacuum dry at 80℃ for 10h to obtain layered siloxane material.

[0074] (2) The layered silicate material obtained in step (1) is placed in a tube furnace and heated to 450°C at a rate of 5°C / min under a nitrogen atmosphere, and held at that temperature for 2 hours. After naturally cooling to room temperature, layered SiO2 can be obtained. x Material.

[0075] The prepared layered SiO x The materials were used to fabricate the negative electrode material for lithium-ion batteries, and the batteries were then subjected to charge and discharge tests.

[0076] Other areas not mentioned are the same as in Example 1.

[0077] The layered SiO prepared in Examples 1-3 x The layered SiOx material prepared in Comparative Example 1 was used as the negative electrode material to assemble lithium-ion coin cells, and constant current charge-discharge tests were conducted. The results are shown in [Figure 1]. Figure 3-5 And Table 1.

[0078] Table 1

[0079] Example 1 1213.24 56.97 Example 2 1045.37 55.29 Example 3 1330.78 61.61 Comparative Example 1 833.22 48.68

[0080] The above description is merely a preferred embodiment of the present invention. These specific embodiments are different implementations based on the overall concept of the present invention, and the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A layered SiO based on interlayer embedding method x The preparation method of the [method] is characterized by, The method described: S1: Disperse layered siloxane material in a solvent, then add small organic molecules, sonicate, and then hydrothermally react under inert gas protection. After the reaction, separate the solid and liquid phases, wash, and dry to obtain siloxane material with interlayer embedded small organic molecules. The small organic molecules are one or more of urea, melamine, thiourea, dopamine, aniline, ethylenediamine, arginine, glutamine, cysteine, thiophene, pyrrole, thiazole, imidazole, pyridine, pyrazole, and carbazole. S2: The interlayered siloxane material with embedded organic small molecules is heat-treated in an inert gas at a temperature of 450~1000℃ for 0.5~24h to obtain layered SiO2. x .

2. The method according to claim 1, characterized in that, Preparation of layered siloxane material in S1: Concentrated acid and silicon metal compound were mixed and stirred for a period of time, then filtered, washed and dried to obtain layered siloxane material.

3. The method according to claim 2, characterized in that, The concentrated acid is one or more of hydrofluoric acid, nitric acid, sulfuric acid, sulfurous acid, hydrochloric acid, phosphoric acid, boric acid, oxalic acid, lactic acid, acetic acid, and citric acid, with a concentration of 0.1~25 mol / L. The silicon metal compound is one or more of vanadium silicide, calcium silicide, titanium silicide, cobalt silicide, tantalum silicide, iron silicide, cerium silicide, niobium silicide, copper silicide, hafnium silicide, zirconium silicide, nickel silicide, tungsten silicide, molybdenum silicide, chromium silicide, manganese silicide, lithium silicide, and sodium silicide. The ratio of silicon metal compound to concentrated acid is 1 g:(10~100) mL. Stir for 0.5~24 h.

4. The method according to claim 1, characterized in that, The solvent in S1 is one or more of the following: water, methanol, ethanol, diethyl ether, ethyl acetate, ethylene glycol, isopropanol, N,N-dimethylformamide, dimethyl sulfoxide, tetrahydrofuran, acetonitrile, acetone, dichloromethane, and N-methylpyrrolidone.

5. The method according to claim 1, characterized in that, The ratio of layered siloxane material to solvent in S1 is 1g:(10~200)mL, the mass ratio of layered siloxane material to organic small molecule material is 1:(0.1~10), the ultrasonic treatment time is 0.5~24h, the hydrothermal reaction temperature is 40~100℃, and the time is 0.5~24h.

6. The method according to claim 1, characterized in that, The inert gas in S1 and S2 is argon or nitrogen.

7. Layered SiO₂ prepared by the method according to any one of claims 1-6 x .

8. The layered SiO as described in claim 7 x It is used as an active material for the negative electrode of batteries.

9. A negative electrode sheet, characterized in that, The negative electrode sheet is made of layered SiO as described in claim 7. x It is prepared from binders and conductive agents.

10. The application of the negative electrode sheet according to claim 9 in a lithium-ion battery.

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