A method for preparing and applying lithium-ion battery anode material; lithium-ion battery

Abstract

This invention provides a method for preparing a lithium-ion battery anode material and its application in lithium-ion batteries. Using MMT as a template, vinyltriethoxysilane (VTES) as the silicon source and resorcinol as the carbon source, the invention prepares MMT@SiO through a sol-gel method, followed by oxidative polymerization and high-temperature calcination. x / C composite material. The introduction of MMT enhances the interfacial bonding with the carbon layer. Its natural layered structure can alleviate the volume expansion stress of the electrode material, and its high specific surface area can adsorb lithium ions and improve conductivity, effectively improving SiO2. x Electrochemical performance of / C materials. After 500 cycles at 2.0 A / g, MMT@SiO x / C has a capacity retention rate as high as 92.36%, which is far higher than that of SiO. x / C capacity retention rate (73.51%).

Description

Technical Field

[0001] The present invention relates to the technical field of lithium-ion batteries, and particularly to a preparation method and application of a lithium-ion battery anode material, and a lithium-ion battery. Background Art

[0002] With the global energy structure transformation towards cleaner and lower-carbon, lithium-ion batteries, as the core components of electric vehicles and renewable energy storage systems, have an increasingly urgent demand for electrode materials with high energy density and long cycle life. Silicon-based anode materials are regarded as a key direction to break through the existing technical bottlenecks because their theoretical specific capacity (4200 mAh / g) far exceeds that of traditional graphite (372 mAh / g). SiO x (silicon monoxide, 0 < x < 2) is an important component of silicon-based materials. Although its theoretical specific capacity (1200 - 1500 mAh / g) is lower than that of elemental silicon, it is still much higher than traditional anode materials. Compared with elemental silicon, SiO x has a lower volume expansion rate (about 100 - 200%), which not only reduces the mechanical stress of the electrode material and significantly improves the cycle stability. SiO x achieves a good balance among specific capacity, volume expansion and cycle stability, and is a highly potential anode material with high energy density. At the same time, SiO x has a relatively low synthesis cost and wide sources, making it widely used in high-energy-density lithium-ion batteries in fields such as consumer electronics and electric vehicles.

[0003] Researchers have also studied its disadvantages and proposed some improvement methods. Among them, materials with special structures are designed to relieve volume changes to improve mechanical properties and electrochemical properties. For example, materials with a nano structure improve mechanical properties; composites are formed with materials having high mechanical strength (such as polymers, metals) to enhance their toughness. At the same time, by element doping or compounding with conductive materials, its conductivity can be enhanced. Currently, carbon nanotubes, metal oxides, etc. are usually used to modify SiO x materials; for example, the prior art discloses a Co nanoparticle-modified SiO x / C composite material with stable high capacity, in which sub-nanoscale SiO x clusters are uniformly dispersed in the in-situ formed carbon matrix.

[0004] However, when using carbon nanotubes, metal oxides, etc. for modification, on the one hand, the raw material costs of carbon nanotubes, metal oxides, etc. are relatively high, and the electrochemical performance improvement of the modified SiO x materials is limited; based on this, it is necessary to make improvements. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method for preparing lithium-ion battery anode materials and their applications in lithium-ion batteries. Compared to modified materials such as carbon nanotubes and metal oxides, montmorillonite (MMT), as a natural mineral, is abundant and inexpensive. This invention uses MMT as a template, vinyltriethoxysilane (VTES) as the silicon source, and resorcinol as the carbon source, and prepares MMT@SiOx / C composite materials through sol-gel method, oxidative polymerization, and high-temperature calcination. The introduction of MMT enhances the interfacial bonding with the carbon layer; its natural layered structure can alleviate the volume expansion stress of the electrode material; its high specific surface area can adsorb lithium ions and improve conductivity, effectively improving SiO2 performance. x Electrochemical performance of / C materials. After 500 cycles at 2.0 A / g, MMT@SiO x / C has a capacity retention rate as high as 92.36%, which is far higher than that of SiO. x / C capacity retention rate (73.51%).

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a method for preparing a lithium-ion battery anode material, comprising the following steps:

[0008] Resorcinol was dissolved in an aqueous ethanol solution, ammonia was added, and the mixture was stirred. Formaldehyde and vinyltriethoxysilane were then added and the mixture was stirred to react, yielding the first precursor.

[0009] The first precursor was calcined under an inert atmosphere to obtain SiO. x / C material;

[0010] Hydrogen-based bentonite was dispersed in water to obtain a suspension;

[0011] Hexadecyltrimethylammonium bromide was added to the suspension, stirred, and subjected to a hydrothermal reaction to obtain a solid product.

[0012] The solid product was dispersed in an aqueous ethanol solution, resorcinol was added and stirred to dissolve it, then ammonia was added and stirred, then formaldehyde and vinyltriethoxysilane were added and stirred to react, thus obtaining the second precursor.

[0013] The second precursor was calcined under an inert atmosphere to obtain MMT@SiO. x / C composite material, which is the lithium battery anode material.

[0014] Preferably, the first precursor is calcined at 700–900°C for 3–4 hours under an inert atmosphere to obtain SiO. x / C material.

[0015] The second precursor was calcined at 700–900 °C for 3–4 h under an inert atmosphere to obtain MMT@SiO. x / C composite material.

[0016] Preferably, the preparation method of the hydrogen-based bentonite includes the following steps:

[0017] Sodium-based bentonite was soaked in sulfuric acid to allow H+ to dissolve. + with Na + An ion exchange reaction occurs, resulting in hydrogen-based bentonite.

[0018] Preferably, resorcinol is dissolved in an ethanol aqueous solution, ammonia is added, and the mixture is stirred for 0.5 to 1 hour. Then, formaldehyde and vinyltriethoxysilane are added, and the mixture is stirred and reacted for 24 to 30 hours to obtain the first precursor.

[0019] The mass-to-volume ratio of resorcinol, aqueous ethanol solution, ammonia, formaldehyde, and vinyltriethoxysilane is (0.1–0.2) g:(28–40) mL:(0.3–0.4) mL:(0.14–0.16) mL:(1–2) mL.

[0020] The mass fraction of the ammonia solution is 25-26%.

[0021] The formaldehyde is an aqueous solution of formaldehyde with a mass fraction of 37-40%;

[0022] The volume ratio of ethanol to water in the ethanol-water solution is (20-25):(8-15).

[0023] Preferably, cetyltrimethylammonium bromide is added to the suspension, stirred, and subjected to a hydrothermal reaction to obtain a solid product, wherein the hydrothermal reaction temperature is 120-130°C and the time is 1-2 hours.

[0024] Preferably, in the step of dispersing hydrogen-based bentonite in water to obtain a suspension; adding hexadecyltrimethylammonium bromide to the suspension, stirring, and then carrying out a hydrothermal reaction to obtain a solid product; dispersing the solid product in an ethanol aqueous solution, adding resorcinol and stirring to dissolve it, then adding ammonia and stirring, then adding formaldehyde and vinyltriethoxysilane and stirring to react to obtain the second precursor, the mass-volume ratio of hydrogen-based bentonite, water, hexadecyltrimethylammonium bromide, ethanol aqueous solution, resorcinol, ammonia, formaldehyde, and vinyltriethoxysilane is (0.1-0.2) g:(20-25) g:(0.01-0.02) g:(28-40) mL:(0.1-0.2) g:(0.3-0.4) mL:(0.14-0.16) mL:(1-2) mL;

[0025] The mass fraction of the ammonia solution is 25-26%.

[0026] The formaldehyde is an aqueous solution of formaldehyde with a mass fraction of 37-40%;

[0027] The volume ratio of ethanol to water in the ethanol-water solution is (20-25):(8-15).

[0028] Preferably, the soaking time is 24–30 hours;

[0029] The sulfuric acid has a mass fraction of 18-25%;

[0030] The mass-to-volume ratio of sodium-based bentonite to sulfuric acid is (0.3–0.4) g:(10–15) mL.

[0031] Secondly, the present invention also provides a lithium battery anode material, characterized in that it is prepared by the aforementioned preparation method.

[0032] Thirdly, the present invention also provides an application of the aforementioned lithium battery anode material in the preparation of lithium batteries.

[0033] Fourthly, the present invention also provides a lithium-ion battery, including a negative electrode, wherein the negative electrode includes a negative electrode current collector and a negative electrode slurry coated on the negative electrode current collector;

[0034] The negative electrode slurry includes a binder, a conductive agent, a solvent, and is prepared by the aforementioned preparation method to obtain a lithium-ion battery negative electrode material or the aforementioned lithium-ion battery negative electrode material.

[0035] Fifthly, the present invention also provides a lithium-ion battery, including a positive electrode, wherein the positive electrode is the positive electrode of the lithium-ion battery.

[0036] The preparation method and application of the lithium-ion battery anode material of the present invention, and the lithium-ion battery thereof, have the following advantages compared with the prior art:

[0037] 1. The method for preparing the lithium-ion battery anode material of the present invention uses MMT as a template, vinyltriethoxysilane (VTES) as a silicon source and resorcinol as a carbon source, and prepares MMT@SiO through sol-gel method, oxidative polymerization and high-temperature calcination. x / C composite material. The introduction of MMT enhances the interfacial bonding with the carbon layer. Its natural layered structure can alleviate the volume expansion stress of the electrode material, and its high specific surface area can adsorb lithium ions and improve conductivity, effectively improving SiO2. x Electrochemical performance of / C materials. After 500 cycles at 2.0 A / g, MMT@SiO x / C has a capacity retention rate as high as 92.36%, which is far higher than that of SiO. x / C capacity retention rate (73.51%). Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 The SiO prepared in Examples 1-3 x / C、MMT@SiO x XRD pattern of / C;

[0040] Figure 2 The MMT@SiO prepared in Examples 1-3 x / C Charge and discharge curves after assembly into a battery;

[0041] Figure 3 HMMT, NaMMT, and MMT@SiO in Example 2 x XRD pattern, adsorption-desorption isotherm, and XPS spectrum of / C-800;

[0042] Figure 4 SiO in Example 2 x / C-800, HMMT and MMT@SiO x Topographical features of the C-800;

[0043] Figure 5 SiO in Example 2 x / C-800 and MMT@SiO x Electrochemical performance of / C-800 after being assembled into a battery. Detailed Implementation

[0044] To facilitate understanding of the present invention, a more comprehensive description of the invention will be provided below in conjunction with specific embodiments. Preferred embodiments of the invention are given in the specific embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention.

[0045] The description order of the following embodiments does not limit the preferred order of the embodiments. Additionally, in the description of this application, the term "comprising" means "including but not limited to". The various embodiments of the present invention may exist in the form of a range; it should be understood that the description in the form of a range is only for convenience and conciseness, and should not be construed as a rigid limitation on the scope of the present invention; therefore, it should be considered that the described range description has specifically disclosed all possible sub-ranges and individual values within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and individual numbers within the range, such as 1, 2, 3, 4, 5, and 6, which applies regardless of the range. Additionally, whenever a numerical range is indicated herein, it means including any cited number (fraction or integer) within the indicated range.

[0046] The present invention provides a method for preparing a lithium-ion battery anode material, comprising the following steps:

[0047] S1. Dissolve resorcinol in an ethanol aqueous solution, add ammonia water, stir, then add formaldehyde and vinyltriethoxysilane, and stir and react to obtain a first precursor;

[0048] S2. Calcinate the precursor under an inert atmosphere to obtain SiO x / C material (0 < x < 2, for example, x = 1.57);

[0049] S3. Disperse amino bentonite in water to obtain a suspension;

[0050] S4. Add cetyltrimethylammonium bromide to the suspension, stir, and then carry out a hydrothermal reaction to obtain a solid product;

[0051] S5. Disperse the solid product in an ethanol aqueous solution, add resorcinol and stir to dissolve it, then add ammonia water, stir, then add formaldehyde and vinyltriethoxysilane, and stir and react to obtain a second precursor;

[0052] Calcinate the second precursor under an inert atmosphere to obtain MMT@SiO x / C composite material, which is the lithium-ion battery anode material.

[0053] In some embodiments, the first precursor is calcined under an inert atmosphere at 700 - 900 °C for 3 - 4 h to obtain SiO x / C material.

[0054] In some embodiments, the second precursor is calcined under an inert atmosphere at 700 - 900 °C for 3 - 4 h to obtain MMT@SiO x / C composite material.

[0055] In some embodiments, the inert atmosphere includes, but is not limited to, at least one of nitrogen, helium, neon, and argon.

[0056] In some embodiments, the preparation method of hydrogen-based bentonite (HMMT) includes the following steps:

[0057] Sodium-based bentonite (NaMMT) was soaked in sulfuric acid to allow H2O to form. + with Na + An ion exchange reaction occurs, resulting in hydrogen-based bentonite.

[0058] Specifically, sodium-based bentonite (NaMMT) is soaked in sulfuric acid, during which time the H+ in the solution... + Together with Na in NaMMT + An ion exchange reaction occurs, gradually opening up the tightly packed interlayer structure of montmorillonite (MMT) and increasing the interlayer spacing. After soaking, the mixture is centrifuged and washed with deionized water until neutral to thoroughly remove residual sulfuric acid and other impurities. Finally, the solid is dried to obtain hydrogen-based bentonite.

[0059] In some embodiments, cetyltrimethylammonium bromide is added to the suspension, and after stirring, a hydrothermal reaction is carried out, wherein the hydrothermal reaction temperature is 120-130°C and the time is 1-2 hours.

[0060] In some embodiments, resorcinol is dissolved in an aqueous ethanol solution, ammonia is added, and the mixture is stirred for 0.5 to 1 hour. Then, formaldehyde and vinyltriethoxysilane are added, and the mixture is stirred and reacted for 24 to 30 hours to obtain the first precursor.

[0061] The mass-to-volume ratio of resorcinol, aqueous ethanol solution, ammonia, formaldehyde, and vinyltriethoxysilane is (0.1–0.2) g:(28–40) mL:(0.3–0.4) mL:(0.14–0.16) mL:(1–2) mL;

[0062] The mass fraction of ammonia in the solution is 25-26%.

[0063] Formaldehyde is an aqueous solution with a mass fraction of 37-40%.

[0064] The volume ratio of ethanol to water in the ethanol-water solution is (20-25):(8-15).

[0065] In some embodiments, hydrogen-based bentonite is dispersed in water to obtain a suspension; hexadecyltrimethylammonium bromide is added to the suspension, and after stirring for 1-2 hours, a hydrothermal reaction is carried out to obtain a solid product;

[0066] The mass-to-volume ratio of hydrogen-based bentonite, water, and hexadecyltrimethylammonium bromide is (0.1–0.2) g: (20–25) mL: (0.01–0.02) g.

[0067] In some embodiments, hydrogen-based bentonite is dispersed in water to obtain a suspension; hexadecyltrimethylammonium bromide is added to the suspension, stirred, and subjected to a hydrothermal reaction to obtain a solid product; the solid product is dispersed in an ethanol aqueous solution, resorcinol is added and stirred to dissolve it, then ammonia is added and stirred, then formaldehyde and vinyltriethoxysilane are added and stirred to react to obtain the second precursor. In this step, the mass-volume ratio of hydrogen-based bentonite, water, hexadecyltrimethylammonium bromide, ethanol aqueous solution, resorcinol, ammonia, formaldehyde, and vinyltriethoxysilane is (0.1-0.2) g:(20-25) g:(0.01-0.02) g:(28-40) mL:(0.1-0.2) g:(0.3-0.4) mL:(0.14-0.16) mL:(1-2) mL;

[0068] The mass fraction of ammonia in the solution is 25-26%.

[0069] Formaldehyde is an aqueous solution with a mass fraction of 37-40%.

[0070] The volume ratio of ethanol to water in an aqueous ethanol solution is (20-25):(8-15).

[0071] In some embodiments, the soaking time is 24–30 hours;

[0072] The mass fraction of sulfuric acid is 18-25%;

[0073] The mass-to-volume ratio of sodium-based bentonite to sulfuric acid is (0.3–0.4) g:(10–15) mL.

[0074] In some embodiments, the preparation method of lithium battery anode material includes the following steps:

[0075] S1, SiO xPreparation of / C: 0.1g of resorcinol was accurately weighed using a high-precision balance and slowly added to a pre-prepared aqueous solution of 20mL deionized water and 8mL anhydrous ethanol. The mixture was stirred until the resorcinol was fully dissolved. Then, 0.3mL of 25% ammonia solution was added and stirred for 1 hour. Next, 0.14mL of formaldehyde (specifically a 37-40% formaldehyde aqueous solution) and 1mL of vinyltriethoxysilane were slowly added sequentially, and the mixture was stirred continuously for 24 hours to ensure complete reaction. After centrifugation and drying, the precursor was obtained and placed in a vacuum tube furnace. Under argon protection, the temperature was increased at 3℃ / min, and calcined at 700, 800, and 900℃ for 3 hours respectively. This successfully prepared SiO2. x / C-700, SiO x / C-800 and SiO x / C-900 Three target products;

[0076] S2. Preparation of hydrogen-based bentonite (HMMT): Accurately weigh 0.3g of sodium-based bentonite (NaMMT) and soak it in an 18% (w / w) sulfuric acid (H2SO4) solution for 24 hours. During this period, the H2O in the solution... + Together with Na in NaMMT + An ion exchange reaction occurs, gradually opening up the tightly stacked interlayer structure of MMT and increasing the interlayer spacing. After soaking, the mixture is centrifuged and washed with deionized water until neutral to thoroughly remove residual sulfuric acid and other impurities. Finally, the solid is dried to obtain hydrogen-based bentonite.

[0077] S3, MMT@SiO x Preparation of / C: Weigh 0.1 g HMMT and ultrasonically disperse it in 20 mL of deionized water to form a stable suspension. Then, add 0.01 g cetyltrimethylammonium bromide (CTAB) to the suspension and stir continuously for 1 h. Subsequently, the suspension was transferred to a reaction vessel and subjected to a hydrothermal reaction at 120°C for 12 hours. After the hydrothermal reaction, the product was centrifuged to obtain a solid product. The solid product was then redispersed in a pre-prepared aqueous solution of 20 mL deionized water and 8 mL anhydrous ethanol, and 0.1 g resorcinol was added. The mixture was stirred until the resorcinol was fully dissolved, and then 0.3 mL of 25% ammonia solution was added and stirred for 1 hour. Next, 0.14 mL of formaldehyde (specifically, a 37-40% formaldehyde aqueous solution) and 1 mL of vinyltriethoxysilane were slowly added sequentially, and the mixture was stirred continuously for 24 hours to ensure a complete reaction. After centrifugation and drying, the precursor was obtained and placed in a vacuum tube furnace. Under argon protection, the precursor was calcined at 700, 800, and 900°C for 3 hours at a heating rate of 3°C / min. This successfully prepared MMT@SiOx / C-700、MMT@SiO x / C-800 and MMT@SiO x The three target products, C-900, yield the lithium battery anode material.

[0078] Compared to modified materials such as carbon nanotubes and metal oxides, montmorillonite (MMT), as a natural mineral, is abundant, inexpensive, and easy to prepare. This invention uses MMT as a template, vinyltriethoxysilane (VTES) as the silicon source, and resorcinol as the carbon source, to prepare MMT@SiO through a sol-gel method, followed by oxidative polymerization and high-temperature calcination. x / C composite material. The introduction of MMT enhances the interfacial bonding with the carbon layer. Its natural layered structure can alleviate the volume expansion stress of the electrode material, and its high specific surface area can adsorb lithium ions and improve conductivity, effectively improving SiO2. x Electrochemical performance of / C materials. After 500 cycles at 2.0 A / g, MMT@SiO x / C has a capacity retention rate as high as 92.36%, which is far higher than that of SiO. x / C capacity retention rate (73.51%)

[0079] Based on the same inventive concept, the present invention also provides a lithium battery anode material, which is prepared by the above-described preparation method.

[0080] Based on the same inventive concept, the present invention also provides an application of the above-mentioned lithium battery anode material in the preparation of lithium batteries.

[0081] Based on the same inventive concept, the present invention also provides a lithium-ion battery, including a negative electrode, the negative electrode including a negative electrode current collector and a negative electrode slurry coated on the negative electrode current collector;

[0082] The negative electrode slurry includes a binder, a conductive agent, a solvent, and is prepared by the above-mentioned preparation method to obtain a lithium battery negative electrode material or the above-mentioned lithium battery negative electrode material.

[0083] Specifically, the aforementioned lithium-ion battery anode material is used as the anode active material. The lithium-ion battery anode material, Super P (Super P is conductive carbon black, used as a conductive agent), and CMC (sodium carboxymethyl cellulose, used as a binder) are mixed in a mass ratio of 7:2:1. Then, deionized water is added as a solvent, and the mixture is stirred in a mixer until it becomes a slurry to obtain the anode slurry. The slurry is then uniformly coated onto copper foil, and after vacuum drying and stamping, the corresponding anode sheet is obtained. The mass-volume ratio of the lithium-ion battery anode material to water is 0.1 g:(0.1~0.15) mL.

[0084] Specifically, the lithium-ion battery of the present invention also includes a separator and an electrolyte. The separator can be a Celgard 2400 type PP separator, and the electrolyte is a 1 mol / L LiPF6 electrolyte. Specifically, a mixed solution of ethylene carbonate (EC), ethyl methyl carbonate (EMC) and diethyl carbonate (DEC) in a volume ratio of 1:1:1 is selected as the solvent, and lithium hexafluorophosphate (LiPF6) is selected as the solute to prepare an electrolyte with a concentration of 1 mol / L.

[0085] The following detailed embodiments further illustrate the preparation method and application of the lithium-ion battery anode material of the present invention, and its application in lithium-ion batteries. This section further explains the content of the present invention in conjunction with specific embodiments, but should not be construed as limiting the present invention. Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in the art.

[0086] In the following examples, sodium-based bentonite was purchased from Maclean Biotechnology Co., Ltd., CAS: 85049-30-5.

[0087] Example 1

[0088] This embodiment provides a method for preparing a lithium-ion battery anode material, including the following steps:

[0089] S1, SiO x Preparation of / C: 0.1 g of resorcinol was accurately weighed using a high-precision balance and slowly added to a pre-prepared mixed solution of 20 mL deionized water and 8 mL anhydrous ethanol. The mixture was stirred until the resorcinol was fully dissolved. Then, 0.3 mL of 25% ammonia solution was added and stirred for 1 h. Next, 0.14 mL of formaldehyde (specifically a 37% formaldehyde aqueous solution) and 1 mL of vinyltriethoxysilane (VTES) were slowly added sequentially, and the mixture was stirred continuously for 24 h to ensure complete reaction. After centrifugation and drying, the first precursor was obtained and placed in a vacuum tube furnace. Under argon protection, the temperature was increased to 700 °C at a rate of 3 °C / min and calcined for 3 h to obtain SiO₂. x / C-700 material;

[0090] S2. Preparation of hydrogen-based bentonite (HMMT): Accurately weigh 0.3g of sodium-based bentonite (NaMMT) and soak it in a 18% sulfuric acid (H2SO4) solution for 24h. After soaking, centrifuge the mixture and wash it with deionized water until neutral to completely remove residual sulfuric acid and other impurities. Finally, dry the solid to obtain hydrogen-based bentonite (HMMT).

[0091] S3, MMT@SiO xPreparation of / C: 0.1 g of hydrogen-based bentonite (HMMT) was weighed and ultrasonically dispersed in 20 mL of deionized water to form a stable suspension. Then, 0.01 g of hexadecyltrimethylammonium bromide (CTAB) was added to the suspension, and the mixture was stirred continuously for 1 h. The suspension was then transferred to a reaction vessel and subjected to a hydrothermal reaction at 120 °C for 12 h. After the hydrothermal reaction was completed, the product was centrifuged to obtain a solid product.

[0092] S4. The solid product was dispersed in an ethanol-water solution of 20 mL deionized water and 8 mL anhydrous ethanol. 0.1 g of resorcinol was added and stirred until fully dissolved. Then, 0.3 mL of 25% ammonia solution was added and stirred for 1 h. Next, 0.14 mL of formaldehyde (specifically, a 37% formaldehyde aqueous solution) and 1 mL of vinyltriethoxysilane (VTES) were slowly added sequentially, and stirring was continued for 24 h to ensure complete reaction. After centrifugation and drying, the second precursor was obtained and placed in a vacuum tube furnace. Under argon protection, the temperature was increased to 700 °C at a rate of 3 °C / min and calcined for 3 h, successfully preparing MMT@SiO. x / C-700, thus obtaining the lithium battery anode material MMT@SiO x / C-700.

[0093] This embodiment also provides a lithium-ion battery that uses the MMT@SiO lithium-ion battery anode material from Embodiment 1. x The C-700 assembly is specifically designed to produce a lithium-ion battery including a negative electrode. The negative electrode is prepared by using the lithium-ion battery negative electrode material MMT@SiO2 prepared in Example 1. x C-700, Super P, and CMC are mixed in a mass ratio of 7:2:1, and then deionized water is added as a solvent. The mixture is stirred in a mixer until it becomes a slurry to obtain a negative electrode slurry. The slurry is then evenly coated onto copper foil, and after vacuum drying and stamping, the corresponding negative electrode sheet is obtained. The mass-volume ratio of lithium battery negative electrode material to water is 0.1g:0.12mL.

[0094] The aforementioned lithium-ion battery also includes a positive electrode (specifically a lithium sheet), a separator, and an electrolyte; the separator is a Celgard 2400 type PP separator, and the electrolyte is a 1 mol / L LiPF6 electrolyte. Specifically, a mixed solution of ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) in a volume ratio of 1:1:1 is selected as the solvent, and lithium hexafluorophosphate (LiPF6) is selected as the solute to prepare an electrolyte with a concentration of 1 mol / L.

[0095] The lithium-ion battery uses a CR2025 battery case as the outer shell. The negative electrode, positive electrode (specifically lithium sheet), separator, electrolyte, and outer shell are assembled into a button cell in a glove box, and then the corresponding electrochemical tests are performed.

[0096] Example 2

[0097] This embodiment provides a method for preparing a lithium-ion battery anode material, similar to Embodiment 1, except that in step S1, the temperature is increased to 800°C at a rate of 3°C / min and calcined for 3 hours to obtain SiO2. x / C-800 material; In step S4, the temperature is increased to 800℃ at a rate of 3℃ / min and calcined for 3h. All other process parameters are the same as in Example 1, and the lithium battery anode material MMT@SiO is finally prepared. x / C-800.

[0098] This embodiment also provides a lithium-ion battery, which is the same as in Embodiment 1, except that it uses the lithium battery anode material MMT@SiO from Embodiment 2. x The assembly of / C-800 is the same as in Example 1.

[0099] Example 3

[0100] This embodiment provides a method for preparing a lithium-ion battery anode material, similar to Embodiment 1, except that in step S1, the temperature is increased to 900°C at a rate of 3°C / min and calcined for 3 hours to obtain SiO2. x / C-900 material; In step S4, the temperature is increased to 900℃ at a rate of 3℃ / min and calcined for 3h. The remaining process parameters are the same as in Example 1, and the lithium battery anode material MMT@SiO is finally prepared. x / C-900.

[0101] This embodiment also provides a lithium-ion battery, which is the same as in Embodiment 1, except that it uses the lithium battery anode material MMT@SiO from Embodiment 3. x The assembly of / C-900 is the same as in Example 1.

[0102] Performance testing

[0103] XRD analysis of HMMT and SiO at different temperatures x / C、MMT@SiO x Characterization analysis was performed on / C, and the results are as follows: Figure 1 As shown. Specifically, Figure 1 In Example 1, 'a' represents HMMT and MMT@SiO2 prepared in Example 1. x / C-700, MMT@SiO prepared in Example 2 x / C-800 and MMT@SiO prepared in Example 3x XRD pattern of / C-900; Figure 1 b represents the SiO2 prepared in Examples 1-3. x / C-700, SiO x / C-800 and SiO x XRD pattern of / C-900; Figure 1 c to d represent the SiO₂ prepared in Example 1, respectively. x / C-700、MMT@SiO x / C-700, SiO2 prepared in Example 2 x / C-800、MMT@SiO x / C-800, SiO2 prepared in Example 3 x / C-900 and MMT@SiO x XRD pattern of / C-900.

[0104] from Figure 1 As can be seen from a, HMMT exhibits a (011) diffraction peak specific to SiO2 at 26.7°. From... Figure 1 As can be seen from b, SiO x / C-700, SiO x / C-800 and SiO x A comparison of the XRD patterns of / C-900 reveals that amorphous SiO2 appears at 22.3° and 43.6°, respectively. x The broad peaks of amorphous carbon indicate that SiO2 prepared at 700, 800, and 900 °C... x / C exhibits amorphous characteristics. Further comparison... Figure 1 SiO at different temperatures in c to e x / C and MMT@SiO x The XRD pattern of / C showed that amorphous SiO2 was observed. x And the peaks of amorphous carbon. Furthermore, in comparison... Figure 1 In the middle a, characteristic diffraction peaks of (011) were also observed. These characteristics fully demonstrate that MMT@SiO x / C material was successfully prepared.

[0105] Figure 2 The charge-discharge curves of batteries assembled from different materials are shown in detail. Figure 2 In the example 'a', SiO2 was prepared in Examples 1-3. x / C-700、MMT@SiO x / C-700, SiO x / C-800、MMT@SiO x / C-800, SiO x / C-900 and MMT@SiOx / C-900 initial charge-discharge curve after being assembled into a battery; Figure 2 b to e are SiO2 prepared in Examples 1 to 3. x / C-700、MMT@SiO x / C-700, SiO x Cycle performance curves of batteries assembled from / C-800, MMT@SiOx / C-800, SiOx / C-900 and MMT@SiOx / C-900.

[0106] right Figure 2 The curve shown in Figure a is analyzed, and the specific data are summarized in Table 1 below. The analysis results show that, under different temperature conditions, compared to SiO₂… x / C material, MMT@SiO prepared using MMT as a template x / C materials exhibit superior performance. MMT@SiO x The initial charge and discharge capacities of / C were improved, and the introduction of MMT effectively improved the SiO2 content. x / C material's ICE (first coulomb efficiency).

[0107] Table 1 - MMT@SiO at different temperatures in Examples 1-3 x / C and SiO x Initial charge / discharge results of the battery assembled in / C

[0108]

[0109]

[0110] Figure 2 Images b to d show the SiO₂ in Examples 1 to 3. x / C and MMT@SiO x Cyclic performance curves of / C material at 700℃, 800℃, and 900℃ under calcination conditions at 0.5 A / g. Data show that, at all test temperatures, MMT@SiO prepared by the MMT template method exhibits superior performance. x The cycling performance of C materials is significantly better than that of SiO. x / C material, confirming that the introduction of MMT improves SiO x Cyclic performance of / C. Comparison of MMT@SiO at different temperatures. x / C material's cycle performance, such as Figure 2 As shown in Figure e, the sample exhibited the best cycling performance at 800℃. Based on this, 800℃ was determined as the optimal calcination temperature, and SiO2 was selected. x / C-800 and MMT@SiO x / C-800 will undergo subsequent system testing to deeply analyze the impact of MMT on SiO x Mechanism for improving the properties of / C materials.

[0111] For NaMMT, HMMT and MMT@SiO in Example 2 x Characterization was performed at -800°C to determine SiO₂. x The growth pattern of / C on the MMT template, and the results are as follows Figure 3 As shown.

[0112] Specifically, Figure 3 In this context, 'a' represents HMMT, NaMMT, and MMT@SiO. x XRD patterns of / C-800, b represents HMMT, NaMMT, and MMT@SiO x / C-800 adsorption-desorption isotherm, where c represents HMMT, NaMMT, and MMT@SiO x / C-800 pore size distribution, d is SiO x / C-800 and MMT@SiO x XPS spectrum of / C-800 (d is C1s spectrum and e is Si 2p spectrum).

[0113] Specifically, Figure 3 In this context, 'a' represents HMMT, NaMMT, and MMT@SiO. x XRD pattern of / C-80. According to the Bragg equation:

[0114] 2d sinθ=nλ;

[0115] Where λ is the incident X-ray wavelength, which is 0.15418 nm (Cu Kα), and θ is the angle between the X-ray and the sample plane. Comparing the XRD patterns of NaMMT and HMMT, it was found that after acidification, the diffraction peak of a certain crystal plane of NaMMT shifted to the left from 7.10° to 5.78°, and the interlayer spacing d increased from 1.2440 nm to 1.5278 nm. This phenomenon is attributed to the change in H... + Ion exchange Na + Subsequently, the interlayer molecular forces increase, triggering an interlayer hydration expansion effect. Further analysis using the BET and BJH methods revealed changes in the specific surface area and evolution of the pore structure of the material, such as... Figure 3 As shown in Figures b and c, the specific surface area of ​​NaMMT was found to be 44.2 m². 2 / g, with an average pore width of 8.9nm; after acidification treatment, the specific surface area of ​​HMMT increased to 76.7m². 2 / g, with the average pore width reduced to 5.7 nm. This result indicates that the acidification process, by disrupting interlayer ionic bonds, promotes the opening of the interlayer structure of the MMT, forming a more abundant porosity. This structure transforms into subsequent SiO₂...x The in-situ growth of / C material provides an ideal template environment.

[0116] Comparison of MMT@SiO x XRD patterns of / -800 and HMMT show that MMT@SiO x The disappearance of the / C-800 diffraction peaks at 5–8° indicates that the interlayer spacing has shrunk from 1.5278 nm in HMMT to an amorphous structure, and the interlayer structure has been disrupted. This result shows that SiO x / C grows within the interlayer structure of MMT. Similarly, comparing the adsorption-desorption isotherms and pore size distribution curves of the two, HMMT exhibits a typical type IV adsorption-desorption isotherm, with a significant hysteresis loop in the P / P0 range of 0.45-1.0, indicating the presence of a large number of mesoporous structures. MMT@SiO... x The isotherm at -800°C transforms into Type I, and the hysteresis loop disappears completely, indicating that the pore structure on the MMT template can serve as a SiO2 substrate. x / C growth site. MMT@SiO x The specific surface area and pore width of / -800 are 84.2m. 2 / g and 2.5nm, the specific surface area increases and the pore width decreases, indicating that SiO2 x The in-situ growth of / C disrupts the original interlayer structure of MMT while constructing a more stable pore network.

[0117] Figure 3 d to e represent SiO₂ x / C-800 and MMT@SiO x XPS spectra of / C-800. In the C1s spectrum, characteristic peaks were observed at CC (284.8 eV), CO (285.8 eV), and C=O (289.5 eV). In the Si 2p spectrum, characteristic peaks were observed at SiC. 2+ (102.5eV), Si 3+ (103.2eV) and Si 4+ The characteristic peak (104.0 eV) was observed. Based on the area of ​​Si in each valence state in the Si 2p spectrum, the average valence state of Si and the unknown quantity x in the chemical formula can be calculated. The specific results are shown in Table 2.

[0118] Table 2 - SiO x / C-800 and MMT@SiO x XPS results for / C-800

[0119] sample <![CDATA[Si 2+ Content (%) <![CDATA[Si 3+ Content (%) <![CDATA[Si 4+ Content (%) Si average valence O content (x) <![CDATA[MMT@SiO x / C-800]]> 21.05 44.98 33.97 3.13 1.57 <![CDATA[SiO x / C-800]]> 16.50 54.46 29.04 3.13 1.57

[0120] As can be seen from Table 2, in SiO x / C-800 and MMT@SiO x In / C-800, the average valence state of Si is 3.13, and the unknown quantity x is 1.57. It is worth noting that although both SiO... x They exist in the same form, both being SiO 1.57 However, the content of Si in different valence states varies.

[0121] The SiO2 in Example 2 was characterized using SEM technology. x / C-800, HMMT and MMT@SiO x The morphological characteristics of / C-800 are as follows: Figure 4 As shown.

[0122] Specifically, Figure 4 In the middle, a and d are SiO x SEM images of / C-800 at different magnifications, b and e are SEM images of HMMT, c and f are SEM images of MMT@SiO x SEM image of / C-800.

[0123] from Figure 4 It can be clearly seen from a and d that SiO x The C-800 material mainly exhibits a microsphere morphology with a particle size of approximately 400–500 nm. Figure 4 Figures b and e clearly demonstrate that HMMT exhibits a layered structure, and this structure is precisely SiO2. x Template for C material growth. Further observation. Figure 4 In c and f, it can be observed that the layered structure of the MMT template has been altered by SiO. x / C material filling. However, in Figure 4 The areas marked by the red dashed lines in c and f show the filled MMT@SiO x In the / C-800 material, some MMT structures remain exposed. These exposed areas can serve as contact points with the electrolyte, which is beneficial for Li + The rapid reposting. Meanwhile, compared to the smooth surface of HMMT, MMT@SiO... x The surface of / C-800 is relatively rough and contains many tiny microspheres; this difference fully demonstrates that SiO x / C material was successfully grown on the MMT template.

[0124] Figure 5 SiO in Example 2 x / C-800 and MMT@SiO x The electrochemical performance of the C-800 assembled into a battery, specifically, at 0.5 A / g ( Figure 5 a), 1.0A / g ( Figure 5 (b) 2.0A / g Figure 5 c), 5.0A / g ( Figure 5 Cyclic performance and rate performance under (d) Figure 5 In the middle, e specifically refers to the rate performance at 0.1 A / g, 0.2 A / g, 0.5 A / g, 1.0 A / g, 2.0 A / g, 5.0 A / g, and 10 A / g.

[0125] from Figure 5 As can be clearly observed in a to c, at 0.5 A / g, 1.0 A / g, and 2.0 A / g, MMT@SiO x The cycle performance of batteries assembled with C-800 is superior to that of SiO. x / C-800 indicates that the introduction of MMT can improve SiO x The specific capacity of / C-800. In particular, after 500 cycles at 2.0 A / g, the MMT@SiO₂... x The C-800 assembled battery retains a capacity of up to 92.36%, while SiO2... x The capacity retention rate of the / C-800 assembly is only 73.51%, a significant difference. Furthermore, from... Figure 5 MMT@SiO can be observed in d. x / C-800 showed no capacity decay after 1500 cycles at 5.0 A / g. This phenomenon demonstrates that introducing MMT can improve the performance of SiO2. x / C-800's cycle stability. Additionally... Figure 5 The rate testing results of the middle e show that the introduction of MMT can improve SiO x / C-800's rate performance.

[0126] It is understood that the technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0127] The above are merely preferred embodiments of this application, and only specifically describe the technical principles of this application. These descriptions are only for explaining the principles of this application and should not be construed as limiting the scope of protection of this application in any way. Based on this explanation, any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application, as well as other specific embodiments of this application that can be conceived by those skilled in the art without creative effort, should be included within the scope of protection of this application.

Claims

1. A method for preparing a lithium anode material, characterized in that, Includes the following steps: Sodium bentonite is soaked in sulfuric acid to make H + Na + exchange reaction with Na The soaking time is 24-30h; the mass fraction of sulfuric acid is 18-25%; the mass-volume ratio of sodium bentonite to sulfuric acid is (0.3-0.4)g:(10-15)mL. Hydrogen-based bentonite was dispersed in water to obtain a suspension; Add hexadecyltrimethylammonium bromide to the suspension, stir, and carry out a hydrothermal reaction to obtain a solid product; the hydrothermal reaction temperature is 120~130℃ and the time is 1~2h. The solid product was dispersed in an aqueous ethanol solution, resorcinol was added and stirred to dissolve it, then ammonia was added and stirred, then formaldehyde and vinyltriethoxysilane were added and stirred to react, thus obtaining the second precursor. The mass-to-volume ratio of the hydrogen-based bentonite, water, hexadecyltrimethylammonium bromide, aqueous ethanol solution, resorcinol, ammonia, formaldehyde, and vinyltriethoxysilane is (0.1~0.2)g:(20~25)g:(0.01~0.02)g:(28~40)mL:(0.1~0.2)g:(0.3~0.4)mL:(0.14~0.16)mL:(1~2)mL; the mass fraction of the ammonia solution is 25~26%; and the formaldehyde solution is an aqueous formaldehyde solution with a mass fraction of 37~40%. The second precursor is calcined at 800°C for 3-4h under inert atmosphere to obtain MMT@SiO x / C composite material, i.e. a lithium negative electrode material.

2. The method for preparing the lithium-ion battery anode material as described in claim 1, characterized in that, The volume ratio of ethanol to water in the ethanol-water solution is (20~25):(8~15).

3. A lithium-ion battery anode material, characterized in that, It is prepared by any one of the preparation methods described in claims 1 to 2.

4. The application of the lithium battery anode material according to claim 3 in the preparation of lithium batteries.

5. A lithium-ion battery, characterized in that, Includes a negative electrode, wherein the negative electrode includes a negative electrode current collector and a negative electrode slurry coated on the negative electrode current collector; The negative electrode slurry comprises a binder, a conductive agent, a solvent, and is prepared by any of the preparation methods described in claims 1 to 2 to obtain a lithium-ion battery negative electrode material or the lithium-ion battery negative electrode material described in claim 3.

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