High-performance layered SiOx based on interlayer embedding method as well as preparation method and application of high-performance layered SiOx

Abstract

The invention discloses high-performance layered SiOx based on an interlayer embedding method and a preparation method and application thereof. The invention belongs to the field of lithium ion battery negative electrode materials. The invention aims to provide high-performance layered SiOx based on an interlayer embedding method as well as a preparation method and application of the high-performance layered SiOx. According to the preparation method, small organic molecules are embedded between layers of siloxy alkene by adopting an interlayer embedding method, and the purposes of regulating and controlling the oxygen content in the layered SiOx material and generating a carbon layer in situ to inhibit interlayer grain growth and heteroatom doping are achieved by adjusting the variety and the content of embedded substances. The layered SiOx material provided by the invention has good electrochemical performance, and has relatively high battery specific capacity when being used as a negative electrode of a lithium ion battery.

Description

Technical Field

[0001] The present invention belongs to the field of lithium ion battery negative electrode materials, and specifically relates to a high-performance layered SiO x and its preparation method and application. Background Art

[0002] As energy storage devices, the performance of lithium-ion batteries plays a crucial role in the development of key industries such as electric vehicles, consumer electronics, and energy storage systems. The performance of anode materials, core components of lithium-ion batteries, directly impacts the overall performance of the battery. While the widely used graphite anode material has mature manufacturing processes and low costs, its energy density is approaching its theoretical limit, making it difficult to meet the growing market demand for high-energy-density batteries.

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

[0004] Layered SiO x The material stands out for its unique structural design, which can effectively alleviate the volume expansion problem of silicon during the cycle and ensure that the battery maintains good cycle performance. However, it cannot be ignored that SiO x Too high oxygen content in the layered SiO will have a negative impact on its lithium storage capacity. x The oxygen content of materials has become a key issue in promoting their practical applications. Furthermore, element doping can effectively improve electrochemical properties such as conductivity. Efficient and controllable element doping is crucial for improving the performance of lithium-ion batteries. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a high-performance layered SiO x The invention also provides a preparation method and application thereof. It adopts the interlayer embedding method to embed organic small molecules between the siloxane layers, and adjusts the type and content of the embedded substances to achieve the purpose of regulating the layered SiO x The oxygen content in the material, the in-situ generation of carbon layer to inhibit interlayer grain growth and heteroatom doping. The layered SiO x The material has good electrochemical properties and has a high battery specific capacity when used as the negative electrode of lithium-ion batteries.

[0006] The technical solutions of the present invention are as follows:

[0007] One of the purposes of the present invention is to provide a high performance layered SiO x The preparation method is carried out according to the following steps:

[0008] S1: Dispersing the layered siloxane material in a solvent, then adding an organic small molecule material, ultrasonically treating, and hydrothermally reacting under inert gas protection. After the reaction is completed, solid-liquid separation is performed to remove the solid phase, wash, and dry the solid phase to obtain a siloxane material with organic small molecules embedded between the layers;

[0009] S2: The siloxane material with small organic molecules embedded between the layers is placed in an inert gas for heat treatment to obtain a high-performance layered SiO x .

[0010] Further defined, the high performance layered SiO based on the interlayer embedding method of the present invention x Preparation method: Preparation of layered siloxene material in S1: Concentrated acid and silicon metal compound are mixed and stirred for a period of time, followed by suction filtration, washing, and drying to obtain a layered siloxene material.

[0011] Further limiting, in the preparation of the layered siloxane material: 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.

[0012] It is further defined that, in the preparation of the layered siloxane material, the concentration of the concentrated acid is 0.1 to 25 mol / L.

[0013] It is further defined that the preparation of layered silicene materials is: 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, tantalum silicide, chromium silicide, manganese silicide, lithium silicide, and sodium silicide.

[0014] It is further defined that in the preparation of the layered siloxane material, the ratio of the silicon metal compound to the concentrated acid is 1 g: (10-100) mL.

[0015] Further limiting the preparation of the layered siloxane material: stirring for 0.5 to 24 hours.

[0016] Further defined, 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, ether, ethyl acetate, ethylene glycol, isopropanol, N,N-dimethylformamide, dimethyl sulfoxide, tetrahydrofuran, acetonitrile, acetone, dichloromethane, and N-methylpyrrolidone.

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

[0018] Further defined, 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 1 g: (10-200) mL.

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

[0020] Further defined, 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 defined, 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°C and the time is 0.5-24h.

[0022] Further defined, 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 defined, 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 defined, 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°C and the time is 0.5-24h.

[0025] The second object of the present invention is to provide a high performance layered SiO x .

[0026] The third object of the present invention is to provide a high performance layered SiO x Used as battery negative electrode active material.

[0027] The fourth object of the present invention is to provide a negative electrode plate, wherein the negative electrode plate is made of the high performance layered SiOx , binder and conductive agent.

[0028] A fifth object of the present invention is to provide an application of the above-mentioned negative electrode plate in a lithium-ion battery.

[0029] Compared with the prior art, the present invention has the following advantages:

[0030] (1) The present invention uses an interlayer embedding method to embed small organic molecules between siloxane layers. A high-temperature heat treatment process triggers the reaction between the interlayer organic small molecules and the oxygen-containing functional groups in the siloxane skeleton, achieving directional regulation of the intrinsic oxygen content of the material. In this process, the in-situ generated nanocarbon layer effectively inhibits the growth of interlayer grains. Simultaneously introduced heteroatom doping can significantly improve the conductivity of the material.

[0031] (2) The present invention can quantitatively adjust the embedding ratio of organic small molecules to form layered SiO x The oxygen content of the material.

[0032] (3) The present invention can realize layered SiO by regulating the types of organic small molecules. x Multi-element controllable doping of materials.

[0033] (4) High-performance layered SiO prepared by the present invention x Materials have made significant progress in improving the electrochemical performance of lithium-ion batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 The high performance layered SiO prepared in Example 1 x SEM images of the materials;

[0035] Figure 2 The high performance layered SiO prepared in Example 1 x XPS graph of the material;

[0036] Figure 3 The high performance layered SiO prepared in Example 1 x The first charge and discharge curve of the material;

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

[0038] Figure 5 The high performance layered SiO prepared in Example 3 x Cycling performance diagram of the material at a current density of 0.5 A / g. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

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

[0041] As used in the following examples, the terms "comprising," "including," "having," "containing," or any other variations thereof, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises the listed elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

[0042] When amount, concentration or other value or parameter are represented with the range of scope, preferred range or a series of upper preferred value and lower preferred value limit, this should be understood as specifically disclosing all ranges formed by any pairing of any range upper limit or preferred value and any range lower limit or preferred value, and no matter whether this scope is disclosed separately.For example, when disclosing scope "1 to 5", described scope should be interpreted as including scope "1 to 4", "1 to 3", "1 to 2", "1 to 2 and 4 to 5", "1 to 3 and 5" etc.When numerical range is described in this article, unless otherwise stated, otherwise this scope is intended to include its end value and all integers and fractions within the scope.In this application specification and claims, range limitation can be combined and / or interchanged, and if these ranges are not otherwise stated, include all subranges contained therein.

[0043] The indefinite articles "a" and "an" before the elements or components of the present invention do not limit the quantity requirement (i.e. the number of times they appear). Therefore, "a" or "an" should be interpreted as including one or at least one, and elements or components in the singular also include plural forms, unless the quantity clearly refers to only the singular form.

[0044] The term "one embodiment" or "embodiment" of the present invention refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in various places throughout this specification does not necessarily refer to the same embodiment, nor does it necessarily refer to a separate or selective embodiment that is mutually exclusive of other embodiments.

[0045] The endpoints of the ranges and any values disclosed in the present 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 endpoints of each range, the endpoints of each range and individual point values, and the individual point values can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be considered to be specifically disclosed herein.

[0046] Example 1

[0047] This embodiment provides a method for preparing high-performance layered SiO x The material method comprises the following steps:

[0048] (1) Add 10 g of iron silicide to 100 mL of 2 mol / L sulfuric acid, mix well, stir for 12 h, wash with deionized water three times, and dry in vacuo at 80 ° C for 10 h to obtain a layered siloxane material;

[0049] (2) Add 0.5 g of the layered siloxane material obtained in step (1) to 20 mL of N,N-dimethylformamide, add 0.5 g of thiophene after uniform dispersion, and ultrasonically treat for 3 hours. Then transfer it to a high-pressure reactor, fill it with nitrogen and expel the air. After sealing, heat it to 100°C and keep it warm for 5 hours, wash it with deionized water 3 times, and vacuum dry it at 80°C for 10 hours to obtain a siloxane material with organic small molecules embedded between the layers;

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

[0051] The SEM of the high performance layered SiOx material obtained in Example 1 is as follows Figure 1 As shown in the figure, it can be seen that this SiO x The material is micron-sized particles with a layered stacking structure, with a large number of gaps between the layers.

[0052] The XPS spectrum of Si 2p of the high performance layered SiOx material obtained in Example 1 is as follows: Figure 2 As shown, according to the peak fitting results, it is composed of Si 0 、Si + and Si 4+ Composition, SiO was calculated based on the peak area ratio x The x value in is 1.29.

[0053] The electrochemical performance of the obtained silicon-based composite negative electrode material was tested by button cells. xThe material is the active material, PAA is used as the binder, and the conductive agent Super P is added in a mass ratio of active material: PAA: Super P = 8:1:1. The mixture is then thoroughly stirred to form a negative electrode slurry. The slurry is then evenly coated on copper foil and baked in an oven at 80°C for 10 hours. After removal, it is rolled and pressed to form the negative electrode sheet.

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

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

[0056] The electrochemical test showed that the charge cut-off voltage was 1.50V and the discharge cut-off voltage was 0.01V.

[0057] Example 2

[0058] This embodiment provides a method for preparing high-performance layered SiO x The material method comprises the following steps:

[0059] (1) Add 2 g of nickel silicide to 100 mL of 10 mol / L nitric acid, mix well, stir for 24 h, wash with deionized water three times, and dry in vacuo at 80 ° C for 10 h to obtain a layered siloxane material;

[0060] (2) Add 1 g of the layered siloxane material obtained in step (1) to 20 mL of water, add 0.2 g of cysteine after uniform dispersion, and ultrasonically treat for 2 h. Then transfer it to a high-pressure reactor, fill it with nitrogen and expel the air. After sealing, heat it to 80°C and keep it warm for 1 h, wash it with deionized water 3 times, and vacuum dry it at 80°C for 10 h to obtain a siloxane material with organic small molecules embedded between the layers;

[0061] (3) The siloxane material with organic small molecules embedded in the interlayer obtained in step (2) is placed in a tube furnace, and the temperature is raised to 450°C at a rate of 5°C / min under an argon atmosphere, and the temperature is kept constant for 1 hour. After naturally cooling to room temperature, a high-performance layered SiO x .

[0062] The prepared layered SiO x The materials are used to make negative electrode materials for lithium-ion batteries, and the batteries are tested for charge and discharge.

[0063] Other unmentioned places are the same as those in Example 1.

[0064] Example 3

[0065] This embodiment provides a method for preparing high-performance layered SiO x The material method comprises the following steps:

[0066] (1) Add 2 g of calcium silicide to 100 mL of 10 mol / L hydrochloric acid, mix well, stir for 12 h, wash with deionized water three times, and vacuum dry at 80 ° C for 10 h to obtain a layered siloxane material;

[0067] (2) Add 1 g of the layered siloxane material obtained in step (1) to 50 mL of isopropanol, add 0.5 g of aniline after uniform dispersion, and ultrasonically treat for 5 h. Then transfer it to a high-pressure reactor, fill it with argon and expel the air. After sealing, heat it to 80°C and keep it warm for 12 h, wash it with deionized water 3 times, and vacuum dry it at 80°C for 10 h to obtain a siloxane material with organic small molecules embedded between the layers;

[0068] (3) The siloxane material with interlayer embedded organic small molecules obtained in step (2) is placed in a tube furnace, and heated to 500°C at a rate of 5°C / min under a nitrogen atmosphere, and kept at this temperature for 1 hour. After naturally cooling to room temperature, a high-performance layered SiO x .

[0069] The prepared layered SiO x The materials are used to make negative electrode materials for lithium-ion batteries, and the batteries are tested for charge and discharge.

[0070] Other unmentioned places are the same as those in Example 1.

[0071] Comparative Example 1

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

[0073] (1) 1 g of calcium silicide was added to 50 mL of 12 mol / L hydrochloric acid, mixed evenly, stirred for 10 h, washed with deionized water three times, and dried in vacuo at 80 ° C for 10 h to obtain a layered siloxane material;

[0074] (2) The layered siloxane material obtained in step (1) was placed in a tube furnace, heated to 450°C at a rate of 5°C / min under a nitrogen atmosphere, and kept at this temperature for 2 hours. After cooling naturally to room temperature, a layered SiO x Material.

[0075] The prepared layered SiO x The materials are used to make negative electrode materials for lithium-ion batteries, and the batteries are tested for charge and discharge.

[0076] Other unmentioned places are the same as those in Example 1.

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

[0078] Table 1

[0079] Sample Description First cycle charge capacity (mAh / g) First-cycle coulombic efficiency (%) 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 foregoing are merely preferred embodiments of the present invention. These embodiments are all different implementations based on the overall concept of the present invention. The scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope 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 based on the scope of protection of the claims.

Claims

1. A high-performance layered SiO based on interlayer embedding method x The preparation method is characterized in that The method: S1: Dispersing the layered siloxane material in a solvent, then adding an organic small molecule material, ultrasonically treating, and hydrothermally reacting under inert gas protection. After the reaction is completed, solid-liquid separation is performed to remove the solid phase, wash, and dry the solid phase to obtain a siloxane material with organic small molecules embedded between the layers; S2: The siloxane material with small organic molecules embedded between the layers is placed in an inert gas for heat treatment to obtain a high-performance layered SiO x .

2. The method according to claim 1, characterized in that Preparation of the layered siloxene material in S1: Concentrated acid and a silicon metal compound are mixed and stirred for a period of time, followed by suction filtration, washing, and drying to obtain a layered siloxene 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 to 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, tantalum silicide, chromium silicide, manganese silicide, lithium silicide, and sodium silicide; the ratio of the silicon metal compound to the concentrated acid is 1 g: (10 to 100) mL, and stirring is performed for 0.5 to 24 hours.

4. The method according to claim 1, wherein The solvent in S1 is one or more of water, methanol, ethanol, ether, ethyl acetate, ethylene glycol, isopropanol, N,N-dimethylformamide, dimethyl sulfoxide, tetrahydrofuran, acetonitrile, acetone, dichloromethane, and N-methylpyrrolidone, and the organic small molecule is one or more of urea, melamine, thiourea, dopamine, aniline, ethylenediamine, arginine, glutamine, cysteine, thiophene, pyrrole, thiazole, imidazole, pyridine, pyrazole, and carbazole.

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

6. The method according to claim 1, characterized in that The inert gas in S1 and S2 is argon or nitrogen, the heat treatment temperature in S2 is 150-1000°C, and the time is 0.5-24h.

7. High-performance layered SiO prepared by the method according to any one of claims 1 to 6 x .

8. The high performance layered SiO according to claim 7 x Used as battery negative electrode active material.

9. A negative electrode plate, characterized in that: The negative electrode sheet is made of the high performance layered SiO x , binder and conductive agent.

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

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