Silicon-carbon composite material, preparation method thereof, negative electrode sheet, electrochemical energy storage device and electric device

Abstract

This application relates to the field of electrochemical energy storage, disclosing a silicon-carbon composite material, its preparation method, a negative electrode sheet, an electrochemical energy storage device, and an electrical device. This application prepares microspherical silicon-carbon composite materials through Michael addition of amino-organosilanes with α-β-unsaturated compounds, Schiff base aldehyde-amine condensation reaction with organic aldehydes, and high-temperature calcination. The silicon-carbon composite material can adjust the content of elements such as Si, O, C, N, and Li by adjusting the types and proportions of reactants. The preparation process is simple, and the material exhibits good stability. When used as a silicon negative electrode material, it does not easily expand during battery cycling, exhibiting excellent characteristics such as high capacity, long cycle life, and low expansion, effectively solving problems such as volume expansion and poor cycle performance during battery charge-discharge cycles.

Description

Technical Field

[0001] This application relates to the field of electrochemical energy storage, and in particular to a silicon-carbon composite material and its preparation method, as well as a negative electrode sheet, an electrochemical energy storage device, and an electrical device. Background Technology

[0002] In recent years, to meet the ever-increasing demands for driving range in electric vehicles, improving battery energy density has become a hot topic. Graphite, a commercially available anode material for lithium-ion batteries, has a theoretical capacity of 372 mAh / g. Silicon materials, with their significant advantages such as high energy density, suitable potential, low cost, abundant resources, and environmental friendliness, have attracted close attention and are very promising to replace carbon materials as the anode material for the next generation of high-energy-density lithium-ion batteries.

[0003] However, silicon typically undergoes a huge volume change (300–400%) during lithium insertion / extraction, leading to the pulverization of active materials and unrestricted growth of the solid electrolyte interface (SEI). The emergence of silicon-carbon materials has effectively alleviated this problem. The carbon framework structure can effectively stabilize the overall structure, mitigate the volume change of silicon in electrochemical reactions, and combine the high conductivity of carbon materials with the high capacity and low potential of silicon-based materials.

[0004] To combine the properties of graphite and silicon, the industry has developed silicon-carbon composite materials. Currently, the most widely accepted practical silicon-carbon composite materials are secondary particles formed by granulation of nano-silicon, graphite, and carbon. For example, patent CN110400927B invented a silicon-carbon composite material containing porous carbon, with an overall core-shell structure. The inner layer consists of nano-silicon, graphite, and porous carbon, while the outer layer is carbon-coated. The porous carbon precursor is added in liquid phase, and the porous structure formed after carbonization is internal, providing limited space for silicon volume changes. Patent CN110828811A discloses a spherical silicon suboxide-graphite composite anode material for lithium-ion batteries and its preparation method. The silicon suboxide raw material and natural graphite raw material are ball-milled separately, then mixed with organic carbon sources such as pitch and spray-dried. However, this method results in materials with low controllability of composition and structure, and the composite effect is not ideal. The preliminary research patent CN 114057178A provides a method for preparing and applying nanocomposite carbon spheres, which in situ composites a large number of groups formed by elements such as Si, O, C, and N, and has a porous structure with a large specific surface area and pore volume. However, it still has the problem of poor cycle performance, and there is an urgent need to further improve it. Summary of the Invention

[0005] In view of this, the purpose of this application is to provide a silicon-carbon composite material and a method for preparing the same, so that the prepared silicon-carbon composite material can suppress the volume expansion of electrochemical energy storage devices and improve their cycle and rate performance.

[0006] Another objective of this application is to provide a negative electrode sheet, an electrochemical energy storage device, and an electrical device based on the silicon-carbon composite material described in this application.

[0007] To achieve all or part of the above objectives, as a first aspect of this application, a method for preparing a silicon-carbon composite material is provided, comprising:

[0008] Amino organosiloxanes and α-β unsaturated compounds undergo a Michael addition reaction to obtain the Michael addition reaction product;

[0009] Amino organosiloxanes and organic aldehydes undergo Schiff base aldehyde-amine condensation reaction to obtain Schiff base aldehyde-amine condensation reaction products.

[0010] The Michael addition reaction product and the Schiff base aldehyde amine condensation reaction product were subjected to hydrolysis to synthesize a silicon-carbon composite material precursor.

[0011] The silicon-carbon composite material precursor is calcined at high temperature in a protective gas atmosphere to obtain the silicon-carbon composite material.

[0012] Optionally, the amino organosiloxane includes one or more of the following: compounds with the structure shown in Formula 1, N-[3-(trimethoxysilyl)propyl]ethylenediamine, 2,2,4,4,6,6-hexamethylcyclotrisilazane, octamethylcyclotetrasilazane, and octaaminopropyl cage-like polysilsesquioxane.

[0013]

[0014] R1, R2, and R3 are each independently selected from -CH3 and C1-C. 10 The alkoxy groups are alkoxy groups, and at least two of R1, R2, and R3 are alkoxy groups; a is an integer from 0 to 10.

[0015] Optionally, the α-β unsaturated compound has the structure shown in Formula 3:

[0016]

[0017] R4 is selected from -CONH2, -C≡N, and -COO-(CH2). b -CH3、-COO - Li + -CONH-C(CH3)2-CH2SO3 - Li + b is an integer between 0 and 10;

[0018] The organic aldehyde has the structure shown in Formula 4:

[0019]

[0020] R5 is selected from -H, -(CH2). c CHO, -COCH3, phenyl, or phenyl with one or more hydroxyl groups arbitrarily substituted, where c is an integer from 0 to 10.

[0021] Optionally, the hydrolysis reaction may further include the addition of a non-amino organosiloxane. More preferably, the non-amino organosiloxane comprises one or more of tetramethoxysilane, tetraethoxysilane, β-cyanoethyltriethoxysilane, methyltrimethoxysilane, benzyltriethoxysilane, vinyltrimethoxysilane, and γ-cyanoethyltriethoxysilane.

[0022] Optionally, the high-temperature calcination temperature is 400–1100°C.

[0023] As a second aspect of this application, a silicon-carbon composite material prepared by the preparation method described in this application is provided.

[0024] As a third aspect of this application, a negative electrode sheet is provided, comprising a current collector and a negative electrode active material coated on at least one surface of the current collector; the negative electrode active material comprises the silicon-carbon composite material described in this application or comprises a silicon-carbon composite material prepared by the preparation method described in this application.

[0025] As a fourth aspect of this application, an electrochemical energy storage device is provided, including the negative electrode sheet described in this application.

[0026] As a fifth aspect of this application, an electrical device is provided, including the electrochemical energy storage device described in this application.

[0027] This application describes the preparation of microspherical silicon-carbon composite materials via Michael addition of amino-organosilanes with α-β-unsaturated compounds, Schiff base aldehyde-amine condensation reaction with organic aldehydes, and high-temperature calcination. The content of elements such as Si, O, C, N, and Li in the silicon-carbon composite material can be adjusted by regulating the types and proportions of reactants. The preparation process is simple, and the material exhibits good stability. When used as a silicon anode material, it does not easily expand during battery cycling, demonstrating excellent characteristics such as high capacity, long cycle life, and low expansion, effectively solving problems such as volume expansion and poor cycle performance during battery charge-discharge cycles. Attached Figure Description

[0028] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute an undue limitation of this application.

[0029] Figure 1 and Figure 2The diagram shown is a schematic representation of the reaction principle of the preparation method of this application. This indicates that the repeating units formed by -Si-O-Si- bonds in the silicon-carbon composite precursor are only present in... Figure 1 and Figure 2 This meaning is present in the formula, and in other structural formulas it indicates the position of the substituent bond breakage;

[0030] Figures 3-10 The diagram shows the long cycle curves for Examples 1, 5, 6, 7, 8, 10, 13 and Comparative Example 1;

[0031] Figure 11 The results shown are the rate performance test results for Examples 1, 8, 18, and Comparative Example 1.

[0032] Figure 12 The impedance curves of Example 1 and Comparative Example 1 are shown below.

[0033] Figure 13 The image shown is a SEM image of Examples 1-4;

[0034] Figure 14 The images shown are SEM images of Examples 5-8;

[0035] Figure 15 The images shown are SEM images of Examples 9-11 and Example 18;

[0036] Figure 16 The Raman curves of Example 1 and Comparative Example 1 are shown. Detailed Implementation

[0037] This application discloses a silicon-carbon composite material and its preparation method, as well as a negative electrode sheet, an electrochemical energy storage device, and an electrical device. Those skilled in the art can refer to the content of this application and appropriately modify the process parameters to achieve the desired results. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included in this application. The products and processes described in this application have been described through preferred embodiments. Those skilled in the art can obviously modify or appropriately change and combine the products and processes described herein without departing from the content, spirit, and scope of this application to realize and apply the technology of this application. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0038] It should be noted that, in this document, relational terms such as "first" and "second," "step 1" and "step 2," and "(1)" and "(2)" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. Moreover, the embodiments and features described in this application can be combined with each other without conflict.

[0039] In the first aspect of this application, a method for preparing a silicon-carbon composite material is provided, comprising:

[0040] Amino organosiloxanes and α-β unsaturated compounds undergo a Michael addition reaction to obtain the Michael addition reaction product;

[0041] Amino organosiloxanes and organic aldehydes undergo Schiff base aldehyde-amine condensation reaction to obtain Schiff base aldehyde-amine condensation reaction products.

[0042] The Michael addition reaction product and the Schiff base aldehyde amine condensation reaction product were subjected to hydrolysis to synthesize a silicon-carbon composite material precursor.

[0043] The silicon-carbon composite material precursor is calcined at high temperature in a protective gas atmosphere to obtain the silicon-carbon composite material.

[0044] In some embodiments of this application, the aminoorganosiloxane includes one or more of the following: compounds with the structure shown in Formula 1, N-[3-(trimethoxysilyl)propyl]ethylenediamine, 2,2,4,4,6,6-hexamethylcyclotrisilazane, octamethylcyclotetrasilazane, and octaaminopropylcage polysilsesquioxane.

[0045]

[0046] R1, R2, and R3 are each independently selected from -CH3 and C1-C. 10The alkoxy group is preferably a straight-chain alkoxy group, and at least two of R1, R2, and R3 are alkoxy groups; a is an integer from 0 to 10. In some other embodiments of this application, R1, R2, and R3 are each independently selected from -CH3, C1-C5 straight-chain alkoxy groups, such as -OCH3, -OCH2CH3, etc.; a is an integer from 1 to 5, such as 1, 2, 3, 4, or 5.

[0047] In other embodiments of this application, the aminoorganosiloxane comprises one or more compounds with the structure shown in Formula 2:

[0048]

[0049] Among them, the compounds with the structure shown in Formula 2 include, but are not limited to, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane and 3-aminopropylmethyldiethoxysilane;

[0050] In some embodiments of this application, the α-β unsaturated compound has the structure shown in Formula 3:

[0051]

[0052] R4 is selected from -CONH2, -C≡N, and -COO-(CH2). b -CH3、-COO - Li + -CONH-C(CH3)2-CH2SO3 - Li + b is an integer from 0 to 10, more preferably an integer from 0 to 5, such as 0, 1, 2, 3, 4, 5. In some other embodiments of this application, the α-β unsaturated compound includes, but is not limited to, one or more of acrylonitrile, methyl acrylate, ethyl acrylate, acrylamide, lithium 2-acrylamido-2-methylpropanesulfonate, and lithium acrylate.

[0053] In some embodiments of this application, the organic aldehyde has the structure shown in Formula 4:

[0054]

[0055] R5 is selected from -H, -(CH2). c CHO, -COCH3, phenyl, or phenyl with one or more hydroxyl groups arbitrarily substituted, where c is an integer from 0 to 10, more preferably an integer from 0 to 5, such as 0, 1, 2, 3, 4, 5.

[0056] In other embodiments of this application, R5 may be specifically selected from -(CH2)3CHO, -(CH2)4CHO, -CHO, etc.; the phenyl group with one or more hydroxyl groups arbitrarily substituted is preferably a phenyl group with one hydroxyl group arbitrarily substituted, for example, it may be specifically selected from any of the following structures:

[0057]

[0058] In other embodiments of this application, the organic aldehydes include, but are not limited to, formaldehyde, glutaraldehyde, glyoxal, acetone aldehyde, adipaldehyde, and salicylaldehyde, or two or more of these.

[0059] In certain embodiments of this application, taking compounds with structures shown in Formulas 2, 3, and 4 as examples, the reaction route for preparing carbon-silicon composite materials in this application is shown below. Figure 1 and Figure 2 .

[0060] Figure 1 The diagram shows the reaction route for synthesizing the precursor of silicon-carbon composite materials, where R6 and R7 are independently selected from -CH3 and -CH4, respectively. The This indicates that the silicon-carbon composite precursor consists of repeating units formed by -Si-O-Si- bonds. The entire silicon-carbon composite precursor is a three-dimensional network structure compound with repeating units formed by "...-Si-O-Si-..." bonds.

[0061] Figure 2 The image shows the silicon-carbon composite material formed after the precursor is sintered at high temperature. During the high-temperature sintering process, the precursor undergoes decomposition, and various bonds recombine and connect, forming a composite material as shown in the image. Figure 2 The three-dimensional mesh material shown has a large silicon-carbon composite structure, therefore... Figure 2 The diagram shown is a partial schematic and is intended to illustrate the reaction principle. It does not impose any limitations on the silicon-carbon composite material structure of this application.

[0062] In some embodiments of this application, the Michael addition reaction conditions include a reaction temperature of 20–30°C and a reaction time of 1.5–12 h. In other embodiments of this application, the amount of the amino-organosilane can be higher than that of the α-β unsaturated compound during the Michael reaction, which facilitates the subsequent direct addition of an organic aldehyde to carry out the Schiff base aldehyde-amine condensation reaction and hydrolysis reaction. In other embodiments of this application, the molar ratio of the amino-organosilane, the α-β unsaturated compound, and the organic aldehyde is 1:(0.1–0.9):(0.9–0.1).

[0063] In some embodiments of this application, the Schiff base aldehyde-amine condensation reaction conditions include a reaction temperature of 20–50°C and a reaction time of 4–24 h. After the reaction is completed, the prepared silicon-oxygen-carbon-nitrogen precursor can be separated and dried by filtration, centrifugation, or spray drying.

[0064] This application introduces carbon-containing compounds in situ through Michael addition, thereby increasing the carbon content of the composite material. To avoid reducing the silicon content, in some embodiments of this application, a non-amino organosiloxane is added during the hydrolysis reaction. In other embodiments of this application, the non-amino organosiloxane includes one or more of tetramethoxysilane, tetraethoxysilane, β-cyanoethyltriethoxysilane, methyltrimethoxysilane, benzyltriethoxysilane, vinyltrimethoxysilane, and γ-cyanoethyltriethoxysilane.

[0065] In some embodiments of this application, the high-temperature calcination temperature is 400–1100°C, and the protective gas includes nitrogen and inert gas. In other embodiments of this application, the high-temperature calcination is divided into two stages: the first stage is calcination at 400–800°C for 1–5 hours, and the second stage is calcination at 800–1100°C for 1–5 hours, with the calcination temperature of the second stage being higher than that of the first stage; for example, calcination at 400°C for 1 hour and calcination at 1100°C for 3 hours.

[0066] In a second aspect of this application, a silicon-carbon composite material prepared by the preparation method described in this application is provided.

[0067] In some embodiments of this application, the silicon-carbon composite material is spherical particles with a particle size of 50 nm to 9 μm, and is composed of Si, O, C and N elements. The proportion of silicon atoms is 7.18% to 14.2%, the proportion of oxygen atoms is 37.3% to 53.5%, the proportion of carbon atoms is 29.2% to 48.3%, and the proportion of nitrogen atoms is 1.16% to 8.35%.

[0068] In a third aspect of this application, a negative electrode sheet is provided, comprising a current collector and a negative electrode active material coated on at least one surface of the current collector; the negative electrode active material comprises the silicon-carbon composite material described in this application or comprises a silicon-carbon composite material prepared by the preparation method described in this application.

[0069] In some embodiments of this application, the negative electrode active material includes the silicon carbide composite material, a conductive agent, and a binder; wherein the mass content of the silicon carbide composite material is 80-90%, the mass content of the conductive agent is 5-10%, and the mass content of the binder is 5-10%. In other embodiments of this application, the conductive agent includes at least one of conductive carbon black, acetylene black, Ketjen black, conductive graphite, and graphene; the binder includes at least one of polyacrylate, polyimide, polyamide, polyamide-imide, polyvinylidene fluoride, styrene-butadiene rubber, sodium alginate, polyvinyl alcohol, polytetrafluoroethylene, polyacrylonitrile, sodium carboxymethyl cellulose, potassium carboxymethyl cellulose, sodium hydroxymethyl cellulose, potassium hydroxymethyl cellulose, and lithium polyacrylate. The current collector can be a highly conductive metal foil, such as copper foil or aluminum foil.

[0070] In some embodiments of this application, a method for preparing the above-mentioned negative electrode sheet is also provided, comprising: mixing the negative electrode active material with a solvent to form a negative electrode slurry, coating it on at least one surface of a current collector to form a functional layer, and obtaining the negative electrode sheet after drying, rolling / cold pressing, or other treatments. The solid content of the negative electrode slurry may be selected as 9-30%, the solvent may be water or other conventional solvents in the art, and the coating thickness of the negative electrode slurry on the current collector (i.e., the thickness before drying, rolling / cold pressing) may be 50-200 μm.

[0071] In a fourth aspect of this application, an electrochemical energy storage device is provided, including the negative electrode sheet described in this application. The electrochemical energy storage device can be a secondary battery, and more particularly, a lithium-ion battery. In some embodiments of this application, the electrochemical energy storage device is a lithium-ion coin cell battery.

[0072] In some embodiments of this application, the electrochemical energy storage device further includes components such as a positive electrode, a separator, and an electrolyte. The electrolyte may be a liquid electrolyte (also known as an electrolyte solution).

[0073] In some embodiments of this application, the liquid electrolyte comprises an organic solvent and an electrolyte lithium salt, and additives may be added as needed; wherein, the organic solvent comprises at least one of fluoroethylene carbonate (FEC), ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), dimethyl carbonate (DMC), propylene carbonate (PCA), and ethyl propionate (EP); more specifically, the organic solvent is any three, further selected from EC, DMC, and any other, with a volume ratio preferably of 1:1:1, such as a mixed solvent of EC+DMC+EMC, a mixed solvent of EC+DMC+FEC, or a mixed solvent of EC+DMC+DEC.

[0074] In some embodiments of this application, the electrolyte lithium salt includes at least one of organic lithium salts and inorganic lithium salts, specifically including at least one of lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium difluorophosphate (LiPO2F2), lithium bis(trifluoromethanesulfonyl)imide LiN(CF3SO2)2 (LiTFSI), lithium bis(fluorosulfonyl)imide Li(N(SO2F)2) (LiFSI), lithium bis(oxalateborate)borate LiB(C2O4)2 (LiBOB), and lithium difluorooxalateborate LiBF2(C2O4) (LiDFOB).

[0075] In some embodiments of this application, the additive includes at least one of crown ether compounds, boron-based compounds, inorganic nano-oxides, carbonate compounds, and amide compounds. For example, it may include at least one of 12-crown-4 ether, boron-based anion acceptor tris(pentafluorophenyl)borane (TFPB), tris(pentafluorophenyl)borate, vinylene carbonate (VC), acetamide and its derivatives.

[0076] In some embodiments of this application, the content of lithium salt in the liquid electrolyte is 0.5 to 1.5 mol / L, for example 0.7 mol / L, 0.9 mol / L, 1.1 mol / L, or 1.3 mol / L.

[0077] In a fifth aspect of this application, an electrical device is provided, including the electrochemical energy storage device described in this application. It can be various electrical devices driven by the electrochemical energy storage device, including but not limited to electric bicycles, electric cars, balance scooters, flatbed trucks, aircraft, lighting equipment, household appliances, etc.

[0078] In the comparative experiments provided in this application, unless otherwise specified, all experimental conditions and materials remain consistent to ensure comparability. Furthermore, all materials used in this application are commercially available.

[0079] The following provides a further description of a silicon-carbon composite material, its preparation method, a negative electrode sheet, an electrochemical energy storage device, and an electrical device provided in this application.

[0080] Example 1:

[0081] (1) Prepare the reaction raw materials: 7.735g of 3-aminopropyltriethoxysilane, 1.42g of 37% formaldehyde aqueous solution, 0.455g of polyvinylpyrrolidone, 0.9275g of acrylonitrile, and 700ml of water for later use. The molar ratio of 3-aminopropyltriethoxysilane:acrylonitrile:formaldehyde is 1:0.5:0.5.

[0082] (2) Preparation of SiOCN precursor: In step one, polyvinylpyrrolidone was added to 700 ml of deionized water and stirred to dissolve. Then, 37% aqueous formaldehyde solution was added. 3-aminopropyltriethoxysilane was mixed with acrylonitrile and stirred for 90 min. Then, it was slowly added dropwise to the aqueous formaldehyde solution. The mixture was heated and stirred at 50°C for 5 hours. The solid was obtained by filtration. The precursor was washed twice with water and ethanol respectively and then dried in an oven at 60°C for 24 h.

[0083] (3) Preparation of SiOCN: Under argon protection, the dried precursor was placed in an alumina crucible and calcined in a tube furnace at 400℃ for 1 h and 1100℃ for 3 h, with a calcination heating rate of 3℃ / min, to obtain the material APTES-0.5ACN-0.5HCHO, which was then ground. SEM images are shown below. Figure 13 .

[0084] (4) Conductivity measurement: After the prepared silicon-oxygen-carbon-nitrogen powder was made into a solid disc under a tablet press, the conductivity was measured to be 0.694 mS / cm using a four-probe instrument.

[0085] (5) The material was subjected to EDS elemental analysis, where (C: 48.29, N: 1.16, O: 37.35, Si: 12.8).

[0086] (6) BET test: The prepared silicon-oxygen-carbon-nitrogen powder was degassed at 300℃ for 5 hours, followed by nitrogen adsorption-desorption. The specific surface area of ​​the material was measured to be 33.401 m². 2 / g, pore volume is 0.037cm³ 3 / g, with a pore diameter of 2.438nm.

[0087] Example 2:

[0088] (1) Prepare the reaction raw materials: 4.42g of 3-aminopropyltriethoxysilane, 2g of 50% glutaraldehyde aqueous solution, 0.26g of polyvinylpyrrolidone, 0.53g of acrylonitrile, and 400ml of water for later use. The molar ratio of 3-aminopropyltriethoxysilane:acrylonitrile:glutaraldehyde is 1:0.5:0.5.

[0089] (2) Preparation of SiOCN precursor: In step one, polyvinylpyrrolidone was added to 400 ml of deionized water and stirred to dissolve. Then, 50% aqueous solution of glutaraldehyde was added. 3-aminopropyltriethoxysilane was mixed with acrylonitrile and stirred for 90 min. Then, it was slowly added dropwise to formaldehyde aqueous solution. The mixture was heated and stirred at 50 °C for 5 hours. The solid was obtained by centrifugation. The precursor was obtained by washing with water and ethanol twice. The precursor was then dried in an oven at 60 °C for 24 h.

[0090] (3) Preparation of SiOCN: Under argon protection, the dried precursor was placed in an alumina crucible and calcined in a tube furnace at 400℃ for 1 h and 1100℃ for 3 h, with a calcination heating rate of 3℃ / min, to obtain material APTES-0.5ACN-0.5GA, which was then ground. SEM images are shown below. Figure 13 .

[0091] (4) Conductivity measurement: After the prepared silicon-oxygen-carbon-nitrogen powder was made into a solid disc under a tablet press, the conductivity was measured to be 0.699 mS / cm using a four-probe instrument.

[0092] (5) The material was subjected to EDS elemental analysis, where (C: 42.72, N: 5.35, O: 40.59, Si: 11.35).

[0093] Example 3:

[0094] (1) Prepare the reaction raw materials: 4.42g of 3-aminopropyltriethoxysilane, 0.81g of 37% formaldehyde aqueous solution, 0.26g of polyvinylpyrrolidone, 1g of ethyl acrylate, and 400ml of water. The molar ratio of 3-aminopropyltriethoxysilane: ethyl acrylate: formaldehyde is 1:0.5:0.5.

[0095] (2) Preparation of SiOCN precursor: In step one, polyvinylpyrrolidone was added to 400 ml of deionized water and stirred to dissolve. Then, 37% formaldehyde aqueous solution was added. 3-aminopropyltriethoxysilane was mixed with ethyl acrylate and stirred for 6 h. Then, it was slowly added dropwise to the formaldehyde aqueous solution. The mixture was heated and stirred at 50 °C for 12 h. The solid was obtained by centrifugation. The precursor was obtained by washing with water and ethanol twice. The precursor was then dried in an oven at 60 °C for 24 h.

[0096] (3) Preparation of SiOCN: Under argon protection, the dried precursor was placed in an alumina crucible and calcined in a tube furnace at 400℃ for 1 h and 1100℃ for 3 h, with a calcination heating rate of 3℃ / min, to obtain the material APTES-0.5EA-0.5HCHO, which was then ground. SEM images are shown below. Figure 13 .

[0097] (4) Conductivity measurement: After the prepared silicon-oxygen-carbon-nitrogen powder was made into a solid disc under a tablet press, the conductivity of the material was measured by a four-probe instrument and found to be lower than the instrument's measurement range.

[0098] Example 4:

[0099] (1) Prepare the reaction raw materials: 4.42g of 3-aminopropyltriethoxysilane, 0.81g of 37% formaldehyde aqueous solution, 0.26g of polyvinylpyrrolidone, 0.71g of acrylamide, and 400ml of water for later use. The molar ratio of 3-aminopropyltriethoxysilane:acrylamide:formaldehyde is 1:0.5:0.5.

[0100] (2) Preparation of SiOCN precursor: In step one, polyvinylpyrrolidone was added to 400 ml of deionized water and stirred to dissolve. Then, 37% aqueous formaldehyde solution was added. 3-aminopropyltriethoxysilane was mixed with acrylamide and stirred for 6 h. Then, it was slowly added dropwise to the aqueous formaldehyde solution. The mixture was heated and stirred at 50 °C for 12 h. The solid was obtained by centrifugation. The precursor was obtained by washing with water and ethanol twice. The precursor was then dried in an oven at 60 °C for 24 h.

[0101] (3) Preparation of SiOCN: Under argon protection, the dried precursor was placed in an alumina crucible and calcined in a tube furnace at 400℃ for 1 h and 1100℃ for 3 h, with a calcination heating rate of 3℃ / min, to obtain material APTES-0.5AM-0.5HCHO, which was then ground. SEM images are shown below. Figure 13 .

[0102] (4) Conductivity measurement: After the prepared silicon-oxygen-carbon-nitrogen powder was made into a solid disc under a tablet press, the conductivity was measured to be 0.463 mS / cm using a four-probe instrument.

[0103] Example 5:

[0104] (1) Prepare the reaction raw materials: 3.58g of 3-aminopropyltrimethoxysilane, 0.81g of 37% formaldehyde aqueous solution, 0.455g of polyvinylpyrrolidone, 0.53g of acrylonitrile, and 400ml of water. The molar ratio of 3-aminopropyltrimethoxysilane:acrylonitrile:formaldehyde is 1:0.5:0.5.

[0105] (2) Preparation of SiOCN precursor: In step one, polyvinylpyrrolidone was added to 400 ml of deionized water and stirred to dissolve. Then, 37% formaldehyde aqueous solution was added. 3-aminopropyltrimethoxysilane was mixed with acrylonitrile and stirred for 4 h. Then, it was slowly added dropwise to the formaldehyde aqueous solution. The mixture was heated and stirred at 50 °C for 12 h. The solid was obtained by filtration. The precursor was washed twice with water and ethanol respectively and then placed in an oven at 60 °C for 24 h to dry.

[0106] (3) Preparation of SiOCN: Under argon protection, the dried precursor was placed in an alumina crucible and calcined in a tube furnace at 400℃ for 1 h and 1100℃ for 3 h, with a calcination heating rate of 3℃ / min, to obtain the material APTMS-0.5ACN-0.5HCHO, which was then ground. SEM images are shown below. Figure 14 .

[0107] (4) Conductivity measurement: After the prepared silicon-oxygen-carbon-nitrogen powder was made into a solid disc under a tablet press, the conductivity was measured to be 57.1 mS / cm using a four-probe instrument.

[0108] (5) The material was subjected to EDS elemental analysis, where (C: 43.94, N: 8.35, O: 40.52, Si: 7.18).

[0109] Example 6:

[0110] (1) Prepare the reaction raw materials: 6.28g of 3-aminopropyltrimethoxysilane, 1.42g of 37% formaldehyde aqueous solution, 0.455g of polyvinylpyrrolidone, 1.75g ​​of ethyl acrylate, and 700ml of water. The molar ratio of 3-aminopropyltrimethoxysilane: ethyl acrylate: formaldehyde is 1:0.5:0.5.

[0111] (2) Preparation of SiOCN precursor: In step one, polyvinylpyrrolidone was added to 700 ml of deionized water and stirred to dissolve. Then, 37% aqueous formaldehyde solution was added. 3-aminopropyltrimethoxysilane was mixed with ethyl acrylate and stirred for 5 h. Then, it was slowly added dropwise to the aqueous formaldehyde solution. The mixture was heated and stirred at 50 °C for 12 h. The solid was obtained by centrifugation. The precursor was obtained by washing with water and ethanol twice. The precursor was then dried in an oven at 60 °C for 24 h.

[0112] (3) Preparation of SiOCN: Under argon protection, the dried precursor was placed in an alumina crucible and calcined in a tube furnace at 400℃ for 1 h and 1100℃ for 3 h, with a calcination heating rate of 3℃ / min, to obtain the material APTMS-0.5EA-0.5HCHO, which was then ground. SEM images are shown below. Figure 14 .

[0113] (4) Conductivity measurement: After the prepared silicon-oxygen-carbon-nitrogen powder was made into a solid disc under a tablet press, the conductivity was measured to be 2.99 mS / cm using a four-probe instrument.

[0114] (5) The material was subjected to EDS elemental analysis, where (C: 40.54, N: 3.01, O: 42.54, Si: 13.9).

[0115] Example 7:

[0116] (1) Prepare the reaction raw materials: 6.28g of 3-aminopropyltrimethoxysilane, 1.42g of 37% formaldehyde aqueous solution, 0.455g of polyvinylpyrrolidone, 1.24g of acrylamide, and 700ml of water for later use. The molar ratio of 3-aminopropyltrimethoxysilane:acrylamide:formaldehyde is 1:0.5:0.5.

[0117] (2) Preparation of SiOCN precursor: In step one, polyvinylpyrrolidone was added to 700 ml of deionized water and stirred to dissolve. Then, 37% aqueous formaldehyde solution was added. 3-aminopropyltrimethoxysilane was mixed with acrylamide and stirred for 12 h. Then, it was slowly added dropwise to the aqueous formaldehyde solution. The mixture was heated and stirred at 50 °C for 12 h. The solid was obtained by spray drying and then placed in an oven at 60 °C for 24 h.

[0118] (3) Preparation of SiOCN: Under argon protection, the dried precursor was placed in an alumina crucible and calcined in a tube furnace at 400℃ for 1 h and 1100℃ for 3 h, with a calcination heating rate of 3℃ / min, to obtain the material APTMS-0.5AM-0.5HCHO, which was then ground. SEM images are shown below. Figure 14 .

[0119] (4) Conductivity measurement: After the prepared silicon-oxygen-carbon-nitrogen powder was made into a solid disc under a tablet press, the conductivity was measured to be 164.5 mS / cm using a four-probe instrument.

[0120] (5) The material was subjected to EDS elemental analysis, in which (C: 42.42, N: 3.18, O: 41.94, Si: 12.46)

[0121] Example 8:

[0122] (1) Preparation of reaction raw materials: 6.7g of 3-aminopropylmethyldiethoxysilane, 1.42g of 37% formaldehyde aqueous solution, 0.455g of polyvinylpyrrolidone, 0.9275g of acrylonitrile, and 700ml of water. The molar ratio of 3-aminopropylmethyldiethoxysilane:acrylonitrile:formaldehyde is 1:0.5:0.5.

[0123] (2) Preparation of SiOCN precursor: In step one, polyvinylpyrrolidone was added to 700 ml of deionized water and stirred to dissolve. Then, 37% aqueous formaldehyde solution was added. 3-aminopropylmethyldiethoxysilane was mixed with acrylonitrile and stirred for 24 h. Then, it was slowly added dropwise to the aqueous formaldehyde solution. The mixture was heated and stirred at 50 °C for 12 h. The solid was obtained by centrifugation and dried in an oven at 60 °C for 24 h.

[0124] (3) Preparation of SiOCN: Under argon protection, the dried precursor was placed in an alumina crucible and calcined in a tube furnace at 400℃ for 1 h and 1100℃ for 3 h, with a calcination heating rate of 3℃ / min, to obtain the material APTMS-0.5AMPSLi-0.5HCHO, which was then ground. SEM images are shown below. Figure 14 .

[0125] (4) Electrical conductivity measurement: After the prepared silicon-oxygen-carbon-nitrogen powder was made into a solid disc under a tablet press, the electrical conductivity of the material was measured to be 0.301 mS / cm using a four-probe instrument.

[0126] (5) The material was subjected to EDS elemental analysis, where (C: 36.86, N: 5.37, O: 43.56, Si: 14.17).

[0127] Example 9:

[0128] (1) Prepare the reaction raw materials: 6.28g of 3-aminopropyltrimethoxysilane, 1.42g of 37% formaldehyde aqueous solution, 0.455g of polyvinylpyrrolidone, 1.365g of lithium acrylate, and 700ml of water for later use. The molar ratio of 3-aminopropyltrimethoxysilane: lithium acrylate: formaldehyde is 1:0.5:0.5.

[0129] (2) Preparation of SiOCN precursor: In step one, polyvinylpyrrolidone was added to 700ml of deionized water and stirred to dissolve. Then, 37% aqueous formaldehyde solution and lithium acrylate were added, followed by slow dropwise addition of 3-aminopropyltrimethoxysilane. The mixture was heated and stirred at 50℃ for 12 hours, and the solid was obtained by centrifugation. The solid was then placed in an oven at 60℃ and dried for 24 hours.

[0130] (3) Preparation of SiOCN: Under argon protection, the dried precursor was placed in an alumina crucible and calcined in a tube furnace at 400℃ for 1 h and 1100℃ for 3 h, with a calcination heating rate of 3℃ / min, to obtain the material APTMS-0.5AALi-0.5HCHO, which was then ground. SEM images are shown below. Figure 15 .

[0131] (4) Electrical conductivity measurement: After the prepared silicon-oxygen-carbon-nitrogen powder was made into a solid disc under a tablet press, the electrical conductivity of the material was measured to be 5.1 mS / cm using a four-probe instrument.

[0132] Example 10:

[0133] (1) Prepare the reaction raw materials: 6.28g of 3-aminopropyltrimethoxysilane, 1.42g of 37% formaldehyde aqueous solution, 0.455g of polyvinylpyrrolidone, 3.63g of 2-acrylamido-2-methylpropanesulfonic acid, 0.771g of LiOH·H2O powder, and 700ml of water. The molar ratio of 3-aminopropyltrimethoxysilane: 2-acrylamido-2-methylpropanesulfonic acid: formaldehyde is 1:0.5:0.5.

[0134] (2) Preparation of SiOCN precursor: In step one, polyvinylpyrrolidone was added to 700 ml of deionized water and stirred to dissolve. Then, 37% aqueous formaldehyde solution, 2-acrylamido-2-methylpropanesulfonic acid, LiOH·H2O powder and 3-aminopropyltrimethoxysilane were added. The mixture was heated and stirred at 50°C for 12 hours. The solid was obtained by centrifugation and dried in an oven at 60°C for 24 hours.

[0135] (3) Preparation of SiOCN: Under argon protection, the dried precursor was placed in an alumina crucible and calcined in a tube furnace at 400℃ for 1 h and 1100℃ for 3 h, with a calcination heating rate of 3℃ / min, to obtain the material APMDES-0.5ACN-0.5HCHO, which was then ground. SEM images are shown below. Figure 15 .

[0136] (4) Conductivity measurement: After the prepared silicon-oxygen-carbon-nitrogen powder was made into a solid disc under a tablet press, the conductivity of the material was measured by a four-probe instrument and found to be lower than the instrument's measurement range.

[0137] (5) BET test: The prepared silicon-oxygen-carbon-nitrogen powder was degassed at 300℃ for 5 hours, followed by nitrogen adsorption-desorption. The specific surface area of ​​the material was measured to be 55.35 m². 2 / g, pore volume is 0.095cm³ 3 / g, with a pore diameter of 4.15nm.

[0138] Example 11:

[0139] (1) Prepare the reaction raw materials: 6.7g of 3-aminopropylmethyldiethoxysilane, 1.42g of 37% formaldehyde aqueous solution, 0.455g of polyvinylpyrrolidone, 1.24g of acrylamide, and 700ml of water. The molar ratio of 3-aminopropylmethyldiethoxysilane:acrylamide:formaldehyde is 1:0.5:0.5.

[0140] (2) Preparation of SiOCN precursor: In step one, polyvinylpyrrolidone was added to 700 ml of deionized water and stirred to dissolve. Then, 37% aqueous formaldehyde solution was added. 3-aminopropylmethyldiethoxysilane was mixed with acrylamide and stirred for 24 h. Then, it was slowly added dropwise to the aqueous formaldehyde solution. The mixture was heated and stirred at 50 °C for 12 h. The solid was obtained by centrifugation and dried in an oven at 60 °C for 24 h.

[0141] (3) Preparation of SiOCN: Under argon protection, the dried precursor was placed in an alumina crucible and calcined in a tube furnace at 400℃ for 1 h and 1100℃ for 3 h, with a calcination heating rate of 3℃ / min, to obtain the material APMDES-0.5AM-0.5HCHO, which was then ground. SEM images are shown below. Figure 15 .

[0142] (4) Conductivity measurement: After the prepared silicon-oxygen-carbon-nitrogen powder was made into a solid disc under a tablet press, the conductivity of the material was measured by a four-probe instrument and found to be lower than the instrument's measurement range.

[0143] Example 12:

[0144] (1) Prepare the reaction raw materials: 6.28g of 3-aminopropyltrimethoxysilane, 1.14g of 37% formaldehyde aqueous solution, 0.455g of polyvinylpyrrolidone, 4.347g of 2-acrylamido-2-methylpropanesulfonic acid, 0.881g of LiOH·H2O powder, and 700ml of water. The molar ratio of 3-aminopropyltrimethoxysilane: 2-acrylamido-2-methylpropanesulfonic acid: formaldehyde is 1:0.6:0.4.

[0145] (2) Preparation of SiOCN precursor: In step one, polyvinylpyrrolidone was added to 700 ml of deionized water and stirred to dissolve. Then, 37% aqueous formaldehyde solution, 2-acrylamido-2-methylpropanesulfonic acid, LiOH·H2O powder and 3-aminopropyltrimethoxysilane were added. The mixture was heated and stirred at 50°C for 12 hours. The solid was obtained by centrifugation and dried in an oven at 60°C for 24 hours.

[0146] (3) Preparation of SiOCN: Under argon protection, the dried precursor was placed in a corundum crucible and calcined in a tube furnace at 400℃ for 1 h and 1100℃ for 3 h. The calcination heating rate was 3℃ / min. The material APTMS-0.6AMPSLi-0.4HCHO was obtained and ground.

[0147] (4) Conductivity measurement: After the prepared silicon-oxygen-carbon-nitrogen powder was made into a solid disc under a tablet press, the conductivity of the material was measured by a four-probe instrument and found to be lower than the instrument's measurement range.

[0148] Example 13:

[0149] (1) Prepare the reaction raw materials: 7.735g of 3-aminopropyltriethoxysilane, 2.27g of 37% formaldehyde aqueous solution, 0.455g of polyvinylpyrrolidone, 0.371g of acrylonitrile, and 700ml of water for later use. The molar ratio of 3-aminopropyltriethoxysilane:acrylonitrile:formaldehyde is 1:0.2:0.8.

[0150] (2) Preparation of SiOCN precursor: In step one, polyvinylpyrrolidone was added to 700 ml of deionized water and stirred to dissolve. Then, 37% aqueous formaldehyde solution was added. 3-aminopropyltriethoxysilane was mixed with acrylonitrile and stirred for 90 min. Then, it was slowly added dropwise to the aqueous formaldehyde solution. The mixture was heated and stirred at 50°C for 5 hours. The solid was obtained by filtration. The precursor was washed twice with water and ethanol respectively and then dried in an oven at 60°C for 24 h.

[0151] (3) Preparation of SiOCN: Under argon protection, the dried precursor was placed in a corundum crucible and calcined in a tube furnace at 400℃ for 1 h and 1100℃ for 3 h. The calcination heating rate was 3℃ / min. The material APTES-0.2ACN-0.8HCHO was obtained and ground.

[0152] (4) Conductivity measurement: After the prepared silicon-oxygen-carbon-nitrogen powder was made into a solid disc under a tablet press, the conductivity of the material was measured by a four-probe instrument and found to be lower than the instrument's measurement range.

[0153] Example 14:

[0154] (1) Preparation of reaction raw materials: 4.42g of 3-aminopropyltriethoxysilane, 0.86g of 37% formaldehyde aqueous solution, 0.26g of polyvinylpyrrolidone, 0.848g of acrylonitrile, and 400ml of water. The molar ratio of 3-aminopropyltriethoxysilane:acrylonitrile:formaldehyde is 1:0.8:0.2.

[0155] (2) Preparation of SiOCN precursor: In step one, polyvinylpyrrolidone was added to 400 ml of deionized water and stirred to dissolve. Then, 37% formaldehyde aqueous solution was added. 3-aminopropyltriethoxysilane was mixed with acrylonitrile and stirred for 90 min. Then, it was slowly added dropwise to the formaldehyde aqueous solution. The mixture was heated and stirred at 50 °C for 12 hours. The solid was obtained by centrifugation. The precursor was washed twice with water and ethanol respectively and then placed in an oven at 60 °C for 24 h to dry.

[0156] (3) Preparation of SiOCN: Under argon protection, the dried precursor was placed in a corundum crucible and calcined in a tube furnace at 400℃ for 1 h and 1100℃ for 3 h. The calcination heating rate was 3℃ / min. The material APTES-0.8ACN-0.2HCHO was obtained and ground.

[0157] (4) Electrical conductivity measurement: After the prepared silicon-oxygen-carbon-nitrogen powder was made into a solid disc under a tablet press, the electrical conductivity of the material was measured to be 40 mS / cm using a four-probe instrument.

[0158] Example 15:

[0159] (1) Preparation of reaction raw materials: 7.735g of 3-aminopropyltriethoxysilane, 2.55g of 37% formaldehyde aqueous solution, 0.455g of polyvinylpyrrolidone, 0.1855g of acrylonitrile, and 700ml of water. The molar ratio of 3-aminopropyltriethoxysilane:acrylonitrile:formaldehyde is 1:0.1:0.9.

[0160] (2) Preparation of SiOCN precursor: In step one, polyvinylpyrrolidone was added to 700 ml of deionized water and stirred to dissolve. Then, 37% aqueous formaldehyde solution was added. 3-aminopropyltriethoxysilane was mixed with acrylonitrile and stirred for 90 min. Then, it was slowly added dropwise to the aqueous formaldehyde solution. The mixture was heated and stirred at 50°C for 5 hours. The solid was obtained by filtration. The precursor was washed twice with water and ethanol respectively and then dried in an oven at 60°C for 24 h.

[0161] (3) Preparation of SiOCN: Under argon protection, the dried precursor was placed in a corundum crucible and calcined in a tube furnace at 400℃ for 1 h and 1100℃ for 3 h. The calcination heating rate was 3℃ / min. The material APTES-0.1ACN-0.9HCHO was obtained and ground.

[0162] (4) Conductivity measurement: After the prepared silicon-oxygen-carbon-nitrogen powder was made into a solid disc under a tablet press, the conductivity of the material was measured by a four-probe instrument and found to be lower than the instrument's measurement range.

[0163] Example 16:

[0164] (1) Prepare the reaction raw materials: 7.735g of 3-aminopropyltriethoxysilane, 1.42g of 37% formaldehyde aqueous solution, 0.455g of polyvinylpyrrolidone, 0.9275g of acrylonitrile, and 700ml of water for later use. The ratio of 3-aminopropyltriethoxysilane:acrylonitrile:formaldehyde:tetraethoxysilane is 1:0.5:0.5:1.

[0165] (2) Preparation of SiOCN precursor: In step one, polyvinylpyrrolidone was added to 700 ml of deionized water and stirred to dissolve. Then, 37% aqueous formaldehyde solution was added. 3-aminopropyltriethoxysilane and acrylonitrile were mixed and stirred for 90 min. Tetraethoxysilane was added and stirred evenly. The silane mixture was slowly added dropwise to the aqueous formaldehyde solution. The mixture was heated and stirred at 50 °C for 5 hours. The solid was obtained by filtration. The precursor was washed twice with water and ethanol respectively and then dried in an oven at 60 °C for 24 h.

[0166] (3) Preparation of SiOCN: Under argon protection, the dried precursor was placed in an alumina crucible and calcined in a tube furnace at 400℃ for 1 h and 1100℃ for 3 h, with a calcination heating rate of 3℃ / min, to obtain the material APTES-0.5ACN-0.5HCHO-TEOS, which was then ground. SEM images are shown below. Figure 15 .

[0167] (4) Conductivity measurement: After the prepared silicon-oxygen-carbon-nitrogen powder is made into a solid disc under a tablet press, the conductivity is measured by a four-probe instrument. The conductivity of the material measured by the four-probe instrument is lower than the instrument's measurement range.

[0168] (5) The material was subjected to EDS elemental analysis, where (C: 24.1, N: 2.14, O: 55.28, Si: 18.48).

[0169] Comparative Example 1:

[0170] (1) Prepare reaction raw materials: 7.735g of 3-aminopropyltriethoxysilane, 2.84g of 37% formaldehyde aqueous solution, 0.455g of polyvinylpyrrolidone, and 700ml of water for later use. The molar ratio of 3-aminopropyltriethoxysilane to formaldehyde is 1:1.

[0171] (2) Preparation of SiOCN precursor: In step one, polyvinylpyrrolidone was added to 700 ml of deionized water and stirred to dissolve. Then, 37% formaldehyde aqueous solution was added. 3-aminopropyltriethoxysilane was slowly added dropwise to the formaldehyde aqueous solution. The mixture was heated and stirred at 50°C for 5 hours. The solid was obtained by filtration. The precursor was obtained by washing with water and ethanol twice. The precursor was then dried in an oven at 60°C for 24 hours.

[0172] (3) Preparation of SiOCN: Under argon protection, the dried precursor was placed in a corundum crucible and calcined in a tube furnace at 400℃ for 3h, 550℃ for 1h, and 1100℃ for 3h. The calcination heating rate was 3℃ / min. The material APTES-HCHO was obtained and ground.

[0173] (4) Conductivity measurement: After the prepared silicon-oxygen-carbon-nitrogen powder was made into a solid disc under a tablet press, the conductivity of the material was measured by a four-probe instrument and found to be lower than the instrument's measurement range.

[0174] (5) The material was subjected to EDS elemental analysis, where (C: 29.21, N: 3.53, O: 53.52, Si: 13.73).

[0175] Comparative Example 2:

[0176] (1) Prepare the reaction raw materials: 2.21g of 3-aminopropyltriethoxysilane, 1.62g of 37% formaldehyde aqueous solution, 0.6g of polyvinylpyrrolidone, 2.08g of tetraethoxysilane, and 200ml of water. The molar ratio of 3-aminopropyltriethoxysilane to tetraethoxysilane to formaldehyde is 1:1.5:2.

[0177] (2) Preparation of SiOCN precursor: In step one, polyvinylpyrrolidone was added to 200 ml of deionized water and stirred to dissolve. Then, 3-aminopropyltriethoxysilane was added. A 37% aqueous solution of formaldehyde and a mixed solution of tetraethoxysilane and ethanol were added dropwise to the above solution. The mixture was stirred at room temperature for 12 hours and centrifuged to obtain a solid. The precursor was washed twice with water and ethanol respectively and then dried in an oven at 60°C for 24 hours.

[0178] (3) Preparation of SiOCN: Under argon protection, the dried precursor was placed in a corundum crucible and calcined in a tube furnace at 400℃ for 1 h and 1100℃ for 3 h. The calcination heating rate was 3℃ / min. The material APTES-1.5TEOS-2HCHO was obtained and ground.

[0179] (4) Conductivity measurement: After the prepared silicon-oxygen-carbon-nitrogen powder was made into a solid disc under a tablet press, the conductivity of the material was measured by a four-probe instrument and found to be lower than the instrument's measurement range.

[0180] Experimental example:

[0181] The silicon-carbon composite material obtained in the examples and comparative examples was slurried with conductive agent Super P and binder CMC and coated onto copper foil current collector to obtain a negative electrode sheet. It was then assembled with lithium foil counter electrode and LiPF6 / EC+DMC+FEC electrolyte to form a 2025 coin cell.

[0182] Button battery test conditions: Charge and discharge cutoff voltage is 0.01-3V. Record the first discharge capacity and charge capacity of the battery. First efficiency = (charge capacity / discharge capacity) × 100%. (Note: The definition of first efficiency is opposite for the positive and negative electrodes. The material in this application is used for the negative electrode. During the first charge and discharge cycle, lithium ions first embed into the electrode sheet made of silicon-carbon composite material from the lithium sheet through discharge, and then detach from the electrode sheet made of silicon-carbon composite material and return to the lithium sheet through charging. Therefore, the first efficiency is defined as (charge capacity / discharge capacity) × 100%).

[0183] Cyclic performance test: charge / discharge current density is 1A / g, voltage range is 0.01V-3V, and test ambient temperature is 25±1℃.

[0184] Volume expansion rate test: The present invention uses a micrometer to measure the thickness of the electrode before and after charging to calculate the expansion rate. The preparation ratio of all electrodes is active material:CMC:SP = 8:1:1, and the thickness of copper foil is 11um. Each set of data is tested 3 times and the average value is taken.

[0185] Table 1 shows the electrode expansion rates of some examples, comparative materials, and conventional silicon suboxide materials used in the battery field. According to the results in Table 1, it can be clearly seen that conventional silicon suboxide materials exhibit significant expansion problems, with an electrode expansion rate as high as 160%. In contrast, the expansion rates of the electrodes prepared from the tested example materials did not exceed 90%, and the electrode expansion rate of Comparative Example 1 was 92%. This indicates that increasing the Michael addition reaction to prepare silicon-carbon composite materials helps to reduce the electrode volume expansion rate and ensure battery safety.

[0186] Table 1 shows the expansion rate data for some examples and comparative models.

[0187] Group Material Name Expansion rate Example 1 APTES-0.5ACN-0.5HCHO 42％ Example 6 APTMS-0.5EA-0.5HCHO 38％ Example 8 APTMS-0.5AMPSLi-0.5HCHO 83％ Example 13 APTES-0.2ACN-0.8HCHO 55％ Comparative Example 1 APTES-HCHO 92％ Standard control silicon suboxide 160％

[0188] Figures 3-10Table 2 shows the long-cycle curves for Examples 1, 5, 6, 7, 8, 10, 13 and Comparative Example 1. Table 2 shows the first-cycle charge-discharge capacity and efficiency and long-cycle capacity retention rate of some examples and comparative examples at 0.2 A / g. The results in the tables show that the battery prepared using the silicon-carbon composite material of this application has superior performance in charge-discharge efficiency and long-cycle capacity retention rate compared with the batteries prepared using materials of Comparative Example 1 (which only underwent Schiff base aldehyde-amine condensation reaction) and Comparative Example 2 (which only used non-amino organosiloxane). The overall performance is better than these two comparative examples.

[0189] Table 2 shows the first-cycle charge-discharge capacity and efficiency, and long-cycle capacity retention data of the examples and comparative examples at 0.2 A / g.

[0190]

[0191]

[0192] Figure 11 The specific capacity of Comparative Example 1, Example 1, Example 8, and Example 18 at different current densities of 0.2, 0.4, 1, 2, 4, and 8 A / g is shown. The results show that the capacity of Example 8 and Example 18 is much greater than that of Comparative Example 1 at all current densities. The capacity of Example 1 is not much different from that of the Comparative Example at low current densities. At current densities greater than 2 A / g, the capacity of Example 1 is greater than that of the Comparative Example. It can be seen that under high current load, Example 1 has less capacity loss. In summary, the materials of the examples can maintain higher capacity at high current densities, charge and discharge rapidly in a short time, and have excellent rate performance.

[0193] Figure 12 The results show the impedance diagrams of Example 1 and Comparative Example 1 after 500 cycles. The battery impedance of Example 1 is 17.2Ω, and the battery impedance of Comparative Example 1 is 25.1Ω. The impedance of Example 1 is 68.5% of that of the Comparative Example, indicating that the Example 1 has faster Li+ ion transport characteristics, which is consistent with the battery rate performance test results.

[0194] Figure 16 The Raman curve results for Example 1 and Comparative Example 1 show that the ID / IG ratio of Example 1 is significantly smaller, indicating less disordered carbon and more graphitic carbon. This confirms that the increased conductivity of Example 1 is related to the increase in graphitic carbon.

[0195] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for preparing a silicon-carbon composite material, characterized in that, include: Amino organosiloxanes and α-β unsaturated compounds undergo a Michael addition reaction to obtain the Michael addition reaction product; Amino organosiloxanes and organic aldehydes undergo Schiff base aldehyde-amine condensation reaction to obtain Schiff base aldehyde-amine condensation reaction products. The Michael addition reaction product and the Schiff base aldehyde amine condensation reaction product were subjected to hydrolysis to synthesize a silicon-carbon composite material precursor. The silicon-carbon composite material precursor is calcined at high temperature in a protective gas atmosphere to obtain the silicon-carbon composite material.

2. The preparation method according to claim 1, characterized in that, The amino organosiloxane includes one or more of the following: compounds with the structure shown in Formula 1, N-[3-(trimethoxysilyl)propyl]ethylenediamine, 2,2,4,4,6,6-hexamethylcyclotrisilazane, octamethylcyclotetrasilazane, and octaaminopropyl cage-like polysilsesquioxane. R1, R2, and R3 are each independently selected from -CH3 and C1-C. 10 The alkoxy groups are alkoxy groups, and at least two of R1, R2, and R3 are alkoxy groups; a is an integer from 0 to 10.

3. The preparation method according to claim 1, characterized in that, The α-β unsaturated compound has the structure shown in Formula 3: R4 is selected from -CONH2, -C≡N, and -COO-(CH2). b -CH3、-COO - Li + -CONH-C(CH3)2-CH2SO3 - Li + b is an integer between 0 and 10; The organic aldehyde has the structure shown in Formula 4: R5 is selected from -H, -(CH2). c CHO, -COCH3, phenyl, or phenyl with one or more hydroxyl groups arbitrarily substituted, where c is an integer from 0 to 10.

4. The preparation method according to claim 1, characterized in that, The hydrolysis reaction also includes the addition of non-amino organosiloxanes.

5. The preparation method according to claim 4, characterized in that, The non-amino organosilanes include one or more of tetramethoxysilane, tetraethoxysilane, β-cyanoethyltriethoxysilane, methyltrimethoxysilane, benzyltriethoxysilane, vinyltrimethoxysilane, and γ-cyanoethyltriethoxysilane.

6. The preparation method according to claim 1, characterized in that, The high-temperature calcination temperature is 400–1100℃.

7. The silicon-carbon composite material prepared by the preparation method according to any one of claims 1-6.

8. A negative electrode sheet, characterized in that, It includes a current collector and a negative electrode active material coated on at least one surface of the current collector; the negative electrode active material includes the silicon-carbon composite material of claim 7.

9. An electrochemical energy storage device, characterized in that, Includes the negative electrode sheet as described in claim 8.

10. An electrical device comprising the electrochemical energy storage device of claim 9.

Images