Process for the preparation of silicon monoxide-carbon composite materials with three-dimensionally ordered macroporous structure and use thereof

Abstract

The application is a preparation method and application of a silicon monoxide-carbon composite material with a three-dimensional ordered macroporous structure. The method uses organosilane as a silicon source, and the organosilane has an organic unit. After experiencing sol-gel and heat treatment, a uniform carbon doping is realized in the final product 3DOM SiO x The structure is combined with chemical vapor deposition to perform uniform carbon coating. The obtained product has a structure similar to a "honeycomb" and a regular ordered macropore. The preparation process is simple, and the product has high repeatability, high capacity, coulomb efficiency and stability. When used as an electrode material of a lithium ion battery, the honeycomb 3DOM structure and the synergistic effect of the carbon combination make the product have excellent electrochemical performance, and show great potential and application value in promoting three-dimensional nanostructure engineering.

Description

Technical Field

[0001] This invention belongs to the fields of nanomaterials and electrochemical energy storage, and specifically relates to a method for preparing a three-dimensional ordered macroporous silicon suboxide-carbon composite material (hereinafter referred to as 3DOM-SC@C) as a negative electrode material for lithium-ion batteries. Background Technology

[0002] Lithium-ion batteries (LIBs) have become the most promising energy storage system among many rechargeable batteries due to their high energy density and high operating voltage. However, the limited capacity (372 mAh / g) of commercial graphite anodes in LIBs cannot meet the growing demand for high energy density in energy storage devices. Therefore, there is an urgent need to develop high-performance novel LIB anode materials (Lee SM, Kim J, Moon J, et al. A cooperative biphasic MoO2). x –MoP x promoter enables a fast-charginglithium-ion battery[J].Nature Communications,2021,12(1):39.).

[0003] silicon suboxide (SiO) x SiO₂ (0 < x ≤ 2) has become a candidate anode material for next-generation high-energy-density LIBs due to its high capacity (~2000 mAh / g). However, during charge-discharge cycling, SiO₂... x It will still expand (~200%) and contract, leading to pulverization and collapse of the electrode material; in addition, its low electronic conductivity and low coulombic efficiency caused by numerous irreversible reactions during lithiation / delithiation processes limit the potential of SiO2. x Practical Applications in Lithium Storage (Ouyang Q, Li G, Zhang X, et al. Towards high-capacity lithium ion batteries: constructing hollow-structured SiO2) x -based nanocube anode via a sequential coating strategy[J].ChemicalEngineering Journal,2023,460,141762.).

[0004] In recent years, numerous studies have shown that constructing nanostructures and combining them with carbon is one of the effective methods to solve the aforementioned problems. In other words, nanostructures reduce the transport paths of ions and electrons to the nanoscale, and their large specific surface area promotes sufficient contact between the electrode and electrolyte, facilitating the complete lithiation process; carbon coating and carbon doping can significantly enhance conductivity, providing a fast pathway for electron and ion transport, while reducing the SiO2 content. x The volume change. The above methods are expected to improve the SiO2 content. x Electrochemical reaction kinetics with Li to obtain high-performance anode materials (Lui G, Li G, Wang X, et al. Flexible, three-dimensional ordered macroporous TiO2 electrode with enhanced electrode-electrolyte interaction in high-power Li-ion batteries[J]. Nano Energy, 2016, 24, 72-77; Li Z, Zhao H, Lv P, et al. Watermelon-like structured SiO2). x -TiO2@Cnanocomposite as a high-performance lithium-ion battery anode[J]. Advanced Functional Materials, 2018, 28, 1605711.).

[0005] However, carbon coating and carbon doping have limited effectiveness in improving electrochemical performance, potentially necessitating the introduction of nanostructures. Currently, 0D, 1D, and 2D nanostructures have been successfully fabricated, effectively enhancing the electrochemical reaction rate of materials. Their large specific surface area provides numerous active sites, exhibiting excellent ion / electron transport kinetics and enhancing lithium storage capacity. Furthermore, electrochemical activity is significantly improved with further reduction in particle size. However, excessively cutting particles into smaller sizes often leads to a substantial increase in energy consumption. In addition, 0D, 1D, and 2D materials tend to accumulate during long-term cycling, resulting in the following problems: (1) hindering mass transfer within the electrode; (2) reducing the contact area between the electrolyte and the electrode, hindering complete lithiation of the active material; (3) their large specific surface area causes more irreversible reactions during cycling, leading to reduced coulombic efficiency. The aforementioned methods and material systems are insufficient for achieving SiO2. xSatisfactory kinetics of the electrochemical reaction with Li. Therefore, combining higher-dimensional nanostructures with carbon may be an effective way to break through the bottleneck. In short, there is an urgent need to develop an effective strategy for synthesizing carbon-coated 3D nanostructure materials and using them to study the electrochemical performance of LIBs anodes, in order to solve their high expansion and low conductivity problems, thereby developing lithium-ion batteries with high energy density and high cycle stability (Wang R, Wang J, Chen S, et al. Toward mechanically stable silicon-based anodes using Si / SiO). x @C hierarchical structures with well-controlled internal buffer voids[J].ACS Applied Materials&Interfaces,2018,10,41422-41430;Ding Y,Wang C,Zheng R,et al.Three-dimensionally orderedmacroporous materials for photo / electrocatalytic sustainable energyconversion,solar cell and energy storage[J].EnergyChem,2022,4,100081.).

[0006] The three-dimensional ordered macroporous (3DOM) structure provides a solution to the above problems. Its advantages are as follows: (1) The three-dimensional open framework provides a convenient way for the efficient transport and diffusion of electrolyte and lithium ions; (2) The 3DOM architecture can also provide sufficient active area to improve the utilization efficiency of electrode materials; (3) The robust and interconnected mesh structure helps to alleviate the volume expansion during lithium insertion and extraction, thereby avoiding mechanical failure and achieving long-term cycle performance.

[0007] Silicon-based materials can also draw on this structure. However, current technologies use tetraethyl orthosilicate as the silicon source and synthesize pure silicon dioxide with a 3DOM structure after a sol-gel process. However, due to the insulating properties of silica, it is difficult to achieve high electrochemical activity when used as an electrode (Jiang Y, Wang Y, Wang H, et al. Facile immobilization of enzyme on three dimensionally ordered macroporous silica via a biomimetic coating[J]. New Journal of Chemistry, 2015, 39(2): 978-984; Han W, Wu S, Dong F, et al. A confined growth strategy to construct 3DOM SiO2 nanooreactor in-situ embedded Co3O4 nanoparticles catalyst for the catalytic combustion of VOCs: Superior H2O and SO2 resistance[J]. Nano Research, 2023: 1-14.). Achieving high conductivity often requires bonding with carbon, but carbon doping in the dense Si-O-Si structure of silica is extremely difficult. Therefore, doping needs to be carried out in the initial stage of material synthesis, that is, before Si-O-Si bonds are formed. Summary of the Invention

[0008] The purpose of this invention is to address the shortcomings of current technologies by proposing a method for preparing and applying a three-dimensional ordered macroporous structure of silica-carbon composite material. This method uses organosilanes as the silicon source, instead of traditional tetraethyl orthosilicate. The organosilanes contain organic units, and after undergoing sol-gel and heat treatment, the final product is 3DOMSiO. x Uniform carbon doping is achieved in the process; this structure is combined with chemical vapor deposition to achieve uniform carbon coating; the resulting product has a honeycomb-like structure and well-ordered macropores. The preparation process of this invention is simple and highly reproducible, and it possesses advantages such as high capacity, coulombic efficiency, and stability. When used as an electrode material for lithium-ion batteries, the synergistic effect of its honeycomb 3DOM structure and carbon bonding gives it excellent electrochemical performance, demonstrating great potential and application value in promoting three-dimensional nanostructure engineering.

[0009] The technical solution of this invention is:

[0010] A method for preparing a silica-carbon composite material with a three-dimensional ordered macroporous structure, the method comprising the following steps:

[0011] (1) The colloidal crystal template (CLPS CCTs) composed of cross-linked polystyrene microspheres is vacuum treated. The catalyst and organosilane are dissolved in ethanol and quickly injected into the treated template. After soaking for 0.1 to 4 hours, the excess liquid is removed and the template is allowed to stand at 10 to 70°C for 0.1 to 30 hours. After drying, a composite material filled with polysilsesquioxane CLPS CCTs is obtained, namely polysilsesquioxane / CLPS.

[0012] The volume ratio of ethanol, catalyst, and organosilane is 0.1–8:0.1–8:1.

[0013] The organosilane is one or more of a siloxane or a chlorosilane;

[0014] The catalyst is ammonia, nitric acid, sulfuric acid, hydrochloric acid, acetic acid, or sodium hydroxide solution;

[0015] (2) Pyrolyze polysilsesquioxane / CLPS in an inert atmosphere at 350-1200℃ for 0.1-20 hours to obtain 3DOM-SC powder; wherein the inert gas is one or both of nitrogen and argon.

[0016] (3) 3DOM-SC powder was subjected to chemical vapor deposition at 350-1200℃ for 0.1-48 hours in a mixed atmosphere to finally obtain a silicon suboxide-carbon composite material with a three-dimensional ordered macroporous structure, namely 3DOM-SC@C;

[0017] Wherein, the mixed atmosphere is a mixture of gas A and gas B; gas A is one or both of nitrogen and argon; gas B is one or more of methane, ethylene, and acetylene; and the volume fraction of gas B is 1-72%.

[0018] The organosilanes mentioned are specifically one or more of vinyltriethoxysilane, 3-aminopropyltriethoxysilane, 3-mercaptopropyltriethoxysilane, methyltrichlorosilane, 3-mercaptopropyltrimethoxysilane, vinyltrimethoxysilane, and trimethylchlorosilane.

[0019] The aforementioned silicon suboxide-carbon composite material with a three-dimensional ordered macroporous structure possesses a three-dimensional ordered macroporous structure with pore sizes ranging from 200 to 500 nm. Regular "window-like" structures exist between the macropores, and the framework is composed of nano-SiO₂. x It consists of a C / C complex and is coated with a carbon coating on its surface.

[0020] The silicon suboxide-carbon composite material with a three-dimensional ordered macroporous structure prepared by the method is used as a negative electrode material for lithium-ion batteries.

[0021] The application of the aforementioned 3DOM-SC@C with three-dimensional ordered macroporous carbon-coated honeycomb structure is characterized by the following lithium-ion battery structure: using a button cell (model CR2430, CR2016 or CR2032), assembled in the order of negative electrode shell, spring sheet, gasket, negative electrode sheet, separator, positive electrode sheet, and positive electrode shell, and filled with an appropriate amount of electrolyte;

[0022] The loading per unit area of ​​the electrode is 1.0–2.0 mg / cm². -2 The negative electrode is the working electrode; the positive electrode is a lithium sheet; the working electrode is obtained by mixing the obtained nanoparticles, acetylene black or Super P, sodium alginate or carboxymethyl cellulose in a mass ratio of 75:10:15 into a slurry, coating it on copper foil, drying it and cutting it into sheets.

[0023] The application of the carbon-coated honeycomb 3DOM-SC@C with three-dimensional ordered macropores, the diaphragm model is Celgard2400;

[0024] The electrolyte is obtained by dissolving lithium hexafluorophosphate in ethylene carbonate, dimethyl carbonate and ethyl methyl carbonate in equal volume ratios, with a concentration of 0.5 to 2.5 mol / L.

[0025] The essential features of this invention are:

[0026] (1) The honeycomb-shaped three-dimensional ordered macroporous material 3DOM-SC@C of the present invention is the first in the silicon-based field to simultaneously achieve doping and coating of silicon suboxide and carbon at the three-dimensional nanoscale; while the existing reports are all based on the synthesis of pure silicon dioxide of 3DOM, and it is very difficult to achieve uniform carbon doping with nanoscale on this basis.

[0027] (2) The pore size of the synthesized honeycomb structure can be precisely adjusted. By using templates of different sizes (50-5000nm), products with different pore sizes can be obtained. Furthermore, when this uniquely structured material is used as a battery, its performance is far superior to that of ordinary bulk non-porous silicon suboxide materials.

[0028] The beneficial effects of this invention are as follows:

[0029] Using polystyrene colloidal crystals as a template, a honeycomb-like three-dimensional ordered macroporous structure was constructed, pioneering a new approach to SiO2 microstructures. x Nanoscale carbon doping and uniform carbon coating were achieved on a three-dimensional ordered macroporous structure. This structure greatly enhances the SiO₂... xThe material exhibits structural stability and possesses the unique advantages of three-dimensional ordered macropores: large specific surface area, large pore size, and interconnected internal regions, effectively enhancing electrolyte transport within the electrode material. Thanks to the synergistic effect of carbon doping, encapsulation, and the honeycomb structure, the reversible capacity of the honeycomb 3DOM-SC@C reaches 930 mAh / g, almost three times that of currently commercial graphite anodes (372 mAh / g), meeting the needs for building next-generation lithium-ion batteries. Furthermore, even after 100 cycles, it still demonstrates a high specific capacity of 721 mAh / g, twice that of graphite anodes. This confirms that the product obtained through this method can effectively cope with significant volume expansion and low conductivity, maintaining structural integrity and promoting efficient electron and ion transport. Attached Figure Description

[0030] To illustrate the embodiments of the present invention in more detail, the accompanying drawings used in the embodiments are briefly described below:

[0031] Figure 1 The flowchart shows the preparation process of 3DOM-SC@C.

[0032] Figure 2 Electron microscope images of each stage in the preparation process of 3DOM-SC@C, where, Figure 2 a is a scanning electron microscope (SEM) image of the CLPS CCTs in Example 1; Figure 2 b is a SEM image of polysilsesquioxane / CLPS in Example 1; Figure 2 c is a 3DOM-SC SEM image, with the inset being a digital image of a real-world cell;

[0033] Figure 3 Here is an electron microscope image of 3DOM-SC@C, in which, Figure 3 a is a SEM image of the honeycomb-shaped 3DOM-SC@C in Example 1. Figure 3 b is the element distribution diagram of the honeycomb-shaped 3DOM-SC@C in Example 1;

[0034] Figure 4 This is a particle size distribution diagram of CLPS CCTs in Example 1;

[0035] Figure 5 The cycling performance of the honeycomb 3DOM-SC@C in Example 1; Detailed Implementation

[0036] The present invention will be further described below through specific embodiments, but the scope of protection of the present invention is not limited to the following embodiments.

[0037] The colloidal crystal templates (CLPS CCTs) composed of regularly arranged cross-linked polystyrene microspheres are known materials and are obtained through typical methods: free radical polymerization, centrifugal sedimentation, and drying (Zhao H, Hu Z, Liu J, et al. Blue-edge slow photons promoting visible-light hydrogen production on gradient ternary 3DOM TiO2-Au-CdS photonic crystals[J]. Nano Energy, 2018, 47: 266-274.).

[0038] Example 1:

[0039] (1) Vacuum treatment of CLPS CCTs (-0.1MPa for 30 minutes), dissolve ammonia (25wt%, 100g) and vinyltrimethoxysilane (100g) in ethanol (100g) and quickly inject the liquid into the template so that the liquid completely covers the template. After soaking for 4 hours, pour out the excess liquid and let it stand at 40°C for 15 hours to heat dry it to obtain polysilsesquioxane / CLPS.

[0040] (2) Pyrolysis of polysilsesquioxane / CLPS at 900℃ for 4 hours yielded a black powder of 3DOM-SC.

[0041] (3) The black powder was placed in a tube furnace and chemical vapor deposition was carried out at 900°C for 1 hour. The gas atmosphere was a mixture of argon and acetylene (volume ratio 90:10) to finally obtain 3DOM-SC@C material.

[0042] Taking the honeycomb-shaped 3DOM-SC@C material obtained in this embodiment as an example. Figure 1 The flowchart of the synthesis process is shown; Figure 2 a shows SEM images of CLPS CCTs, with microspheres having a particle size of approximately 250 nm; Figure 2 b is the product polysilsesquioxane / CLPS after the template is filled with polysilsesquioxane. It can be clearly seen that the gaps in the template are filled with polysilsesquioxane. Figure 2 c is a honeycomb 3DOM-SC material, and it can be found that a three-dimensional ordered macroporous structure has been successfully prepared, and its morphology is very similar to that of a real honeycomb.

[0043] Figure 3 SEM images and element distribution maps of the honeycomb-shaped 3DOM-SC@C are shown. Figure 3 This confirms that the honeycomb structure still has an ordered macroporous morphology and ultrathin pore walls (~14nm); Figure 2b shows the distribution of Si, O, and C elements. It can be seen that the distribution of each element is very uniform. In addition, the dense distribution of carbon elements also confirms the successful coating of carbon.

[0044] Figure 4 The particle size distribution of the CLPS CCTs template is shown, confirming that the template has a narrow particle size distribution with an average size of 253.9 nm. The honeycomb 3DOM-SC@C prepared in this example is assembled into a coin cell, and its electrochemical performance is tested.

[0045] The coin cell is assembled in the following order: negative electrode shell, spring plate, gasket, negative electrode plate, separator, positive electrode plate, and positive electrode shell, and filled with an appropriate amount of electrolyte; the coin cell model is CR2032; the electrode plate load per unit area is 1.5 mg / cm². -2 The negative electrode is the working electrode; the positive electrode is a lithium sheet; the working electrode is obtained by mixing the obtained nanoparticles, Super P, and carboxymethyl cellulose in a mass ratio of 75:10:15 to form a slurry, coating it on copper foil, drying it, and cutting it into sheets; the electrolyte is obtained by dissolving lithium hexafluorophosphate in equal volume ratios of ethyl methyl carbonate, dimethyl carbonate, and ethylene carbonate, with a concentration of 1.0 mol / L.

[0046] Figure 5 For the range of 0.01-3.0V (vs. Li / Li) + Under the voltage window, the current density is 0.1Ag. -1 Constant current charge-discharge tests conducted using the LAND CT-2001A battery testing system showed that the reversible capacity of the honeycomb 3DOM-SC@C was 930 mAh / g, and it still exhibited a high specific capacity (approximately 721 mAh / g) even after 100 cycles.

[0047] The reversible capacity of the honeycomb 3DOM-SC@C reaches 930mAh / g, which is almost three times the capacity of the current commercial graphite anode (372mAh / g), meeting the needs of building the next generation of new lithium-ion batteries.

[0048] Example 2:

[0049] (1) Vacuum treatment of CLPS CCTs (-0.1MPa for 30 minutes), dissolve ammonia (100g), 3-mercaptopropyltriethoxysilane (50g) and vinyltriethoxysilane (50g) in ethanol (100g) and quickly inject the liquid into the template so that the liquid completely covers the template. After soaking for 4 hours, pour out the excess liquid and let it stand at 55°C for 4 hours to heat dry, to obtain polysilsesquioxane / CLPS.

[0050] (2) Pyrolysis of polysilsesquioxane / CLPS at 700℃ for 3 hours yields 3DOM-SC.

[0051] (3) The black powder was placed in a tube furnace and chemical vapor deposition was carried out at 800°C for 4 hours. The gas atmosphere was a mixture of argon and methane (volume ratio 75:25) to finally obtain 3DOM-SC@C material.

[0052] Example 3:

[0053] (1) Vacuum treatment of CLPS CCTs (-0.1MPa for 30 minutes) was performed. Sodium hydroxide solution (15wt.%, 30g), 3-aminopropyltriethoxysilane (25g), vinyltrimethoxysilane (25g), 3-mercaptopropyltriethoxysilane (25g), and vinyltriethoxysilane (25g) were dissolved in ethanol (20g) and quickly injected into the template so that the liquid completely covered the template. After soaking for 4 hours, the excess liquid was poured out and the template was allowed to stand at 25°C for 24 hours to dry, thus obtaining polysilsesquioxane / CLPS.

[0054] (2) Pyrolysis of polysilsesquioxane / CLPS at 850℃ for 4 hours yielded 3DOM-SC.

[0055] (3) The black powder was placed in a tube furnace and chemical vapor deposition was carried out at 850°C for 2.5 hours. The gas atmosphere was a mixture of nitrogen and acetylene (volume ratio 50:50) to finally obtain 3DOM-SC@C material.

[0056] Example 4:

[0057] (1) Vacuum treatment of CLPS CCTs (-0.1MPa for 30 minutes), dissolve acetic acid solution (15wt.%, 30g) and 3-mercaptopropyltriethoxysilane (100g) in ethanol (20g) and quickly inject the solution into the template so that the liquid completely covers the template. After soaking for 4 hours, pour out the excess liquid and let it stand at 25°C for 24 hours to dry, thus obtaining polysilsesquioxane / CLPS.

[0058] (2) Pyrolysis of polysilsesquioxane / CLPS at 700℃ for 4 hours yields 3DOM-SC.

[0059] (3) The black powder was placed in a tube furnace and chemical vapor deposition was carried out at 850°C for 2.5 hours. The gas atmosphere was a mixture of nitrogen and acetylene (volume ratio 50:50) to finally obtain 3DOM-SC@C material.

[0060] Matters not covered in this invention are common knowledge.

Claims

1. A method for preparing a silica-carbon composite material with a three-dimensional ordered macroporous structure, characterized in that the method comprises the following steps: (1) The colloidal crystal template (CLPS CCTs) composed of cross-linked polystyrene microspheres is vacuum treated. The catalyst and organosilane are dissolved in ethanol and then injected into the treated template. After soaking for 0.1 to 4 hours, the excess liquid is removed and the template is allowed to stand at 10 to 70°C for 0.1 to 30 hours. After drying, a composite material filled with polysilsesquioxane CLPS CCTs is obtained, namely polysilsesquioxane / CLPS. in, The volume ratio of ethanol, catalyst, and organosilane is 0.1–8:0.1–8:1; The organosilane is one or more of a siloxane or a chlorosilane; The catalyst is ammonia, nitric acid, sulfuric acid, hydrochloric acid, acetic acid, or sodium hydroxide solution; (2) Pyrolyze polysilsesquioxane / CLPS in an inert atmosphere at 350-1200℃ for 0.1-20 hours to obtain 3DOM-SC powder; (3) 3DOM-SC powder was subjected to chemical vapor deposition at 350-1200℃ for 0.1-48 hours in a mixed atmosphere to finally obtain a silicon suboxide-carbon composite material with a three-dimensional ordered macroporous structure, namely 3DOM-SC@C; The mixed atmosphere is a mixture of gas A and gas B; gas A is one or both of nitrogen and argon; gas B is one or more of methane, ethylene, and acetylene; and the volume fraction of gas B is 1-72%.

2. The method for preparing the silica-carbon composite material with a three-dimensional ordered macroporous structure as described in claim 1, characterized in that the organosilane is specifically one or more of vinyltriethoxysilane, 3-aminopropyltriethoxysilane, 3-mercaptopropyltriethoxysilane, methyltrichlorosilane, 3-mercaptopropyltrimethoxysilane, vinyltrimethoxysilane, and trimethylchlorosilane.

3. The method for preparing the silica-carbon composite material with a three-dimensional ordered macroporous structure as described in claim 1, characterized in that: The inert gas is one or both of nitrogen and argon.

4. The method for preparing the silicon suboxide-carbon composite material with a three-dimensional ordered macroporous structure as described in claim 1, characterized in that the composite material has a three-dimensional ordered macroporous structure, the pore size of the macropores is 200-500 nm, there are regular "windows" between the macropores, and the framework is composed of nano-SiO₂. x It consists of a C / C complex and is coated with a carbon coating on its surface.

5. The application of the silicon suboxide-carbon composite material with a three-dimensional ordered macroporous structure prepared by the method of claim 1, characterized in that it is used as a negative electrode material for lithium-ion batteries.

6. The application as described in claim 5, Its characteristic is the structure of the lithium-ion battery: it adopts a button cell, which is assembled in the order of negative electrode shell, spring sheet, gasket, negative electrode sheet, separator, positive electrode sheet, and positive electrode shell, and is filled with electrolyte; The loading per unit area of ​​the electrode is 1.0–2.0 mg / cm². -2 The negative electrode is the working electrode; the positive electrode is a lithium sheet; the working electrode is obtained by mixing the obtained nanoparticles, acetylene black or Super P, sodium alginate or carboxymethyl cellulose in a mass ratio of 75:10:15 into a slurry, coating it on copper foil, drying it and cutting it into sheets. The diaphragm model is Celgard 2400; The electrolyte is obtained by dissolving lithium hexafluorophosphate in ethylene carbonate, dimethyl carbonate and ethyl methyl carbonate in equal volume ratios, with a concentration of 0.5 to 2.5 mol / L.

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