Carbon / silicon-polymer composite and processes for preparing the same

Abstract

This invention relates to carbon / silicon-polymer composites and their preparation methods. The carbon / silicon-polymer composites according to examples of this invention exhibit excellent uniformity in polymer film thickness. The polymer film has almost no effect on conductivity and lithium-ion conductivity; therefore, when used as a negative electrode material, it serves as a stable solid electrolyte interface layer while maintaining high specific power and coulombic efficiency, thereby suppressing the reduction in battery performance and lifespan.

Description

Technical Field

[0001] This invention relates to carbon / silicon polymer composites, and more specifically, to carbon / silicon polymer composites and methods for their preparation. Prior Technology

[0002] Recently, with the development of the information and communication industry, the demand for electronic devices has surged, and with the active electric vehicle market, the demand for these electronic devices or batteries used in electric vehicles has also increased significantly.

[0003] Lithium-ion secondary batteries, including those containing liquid electrolytes and all-solid-state batteries, are widely used for this purpose due to their high energy density and low self-discharge when not in use. Secondary batteries generally consist of a positive electrode, a negative electrode, and an electrolyte (liquid or solid). Carbon-based materials such as graphite are widely used as negative electrode materials in secondary batteries.

[0004] Recently, silicon-based anode materials have been explored to improve the capacity of rechargeable batteries. Silicon theoretically has a very high energy density, making it a promising next-generation battery anode material to replace graphite. However, due to its reaction with lithium during charging and discharging, its volume increases by up to about 300%, leading to a significant decrease in mechanical stability as charging and discharging progresses. For example, silicon used as an anode material may break down.

[0005] To address these issues, Japanese Patent No. 4393610 discloses a negative electrode material in which silicon is combined with carbon during machining and a carbon layer is coated on the surface of silicon particles using chemical deposition (CVD). However, this method has limitations in suppressing volume expansion and contraction during charging and discharging.

[0006] In addition, the excessive solid electrolyte interphase (SEI) layer generated during the micronization process of silicon-based anode materials by crushing silicon raw materials exhibits instability, thus leading to problems with battery stability and decreased electrical performance. Existing technical documents Patent documents Patent Document 0001: Japanese Patent Publication No. 4393610 Summary of the Invention

[0007] The object of the present invention is to provide a carbon / silicon polymer composite, which forms a polymer film on a carbon-silicon composite whose pores and / or surface are coated with silicon on a porous carbon support having controlled pore characteristics.

[0008] Another object of the present invention is to provide a method for preparing the carbon / silicon polymer composite.

[0009] Another object of the present invention is to provide a negative electrode material comprising the carbon / silicon polymer composite.

[0010] The present invention provides a carbon / silicon polymer composite, comprising: a carbon-silicon composite including a porous carbon support and silicon disposed on the surface and inside the pores of the porous carbon support; and a polymer film disposed on the surface, inside the pores of the porous carbon support and on the surface of the silicon.

[0011] According to one embodiment of the present invention, the BET specific surface area of ​​the porous carbon support can be 300~3000m2 / g, the tap density can be 0.05~0.5g / mL, and the average particle size can be 1~20μm.

[0012] Furthermore, silicon may account for 5 to 80% of the total weight of the carbon / silicon polymer composite.

[0013] Furthermore, the polymer film may account for 1 to 30% of the total weight of the carbon / silicon polymer composite.

[0014] Furthermore, the thickness of the polymer film can be 1~450 nm.

[0015] Furthermore, the present invention provides a method for preparing a carbon / silicon polymer composite, the method comprising: step (1), preparing a carbon-silicon composite by forming silicon on the surface and inside the pores of a porous carbon support; and step (2), forming a polymer film on the surface of the porous carbon support, inside the pores, and on the surface of silicon of the carbon-silicon composite by initiator-based chemical vapor deposition (iCVD) to prepare the carbon / silicon polymer composite.

[0016] According to one embodiment of the present invention, step (2) may include: step (2-1), supplying a carbon-silicon composite into a reactor; step (2-2), supplying a monomer and an initiator into the reactor supplying the carbon-silicon composite; and step (2-3), polymerizing the monomer by initiating the initiator to form a polymer film on the surface of the porous carbon support of the carbon-silicon composite, inside the pores and on the surface of the silicon.

[0017] Furthermore, in step (2-2), the monomer can be supplied at a flow rate of 0.1 sccm to 10 sccm, and the initiator can be supplied at a flow rate of 0.1 sccm to 5 sccm.

[0018] Furthermore, the initiator can be activated by a predetermined heat treatment, which can be performed at a temperature of 135~350°C.

[0019] Furthermore, steps (2-3) can be performed under a vacuum of 50-1000 mTorr for 10 minutes to 6 hours.

[0020] Furthermore, the present invention provides a negative electrode material comprising the carbon / silicon polymer composite as described above, and a carbon-based negative electrode material.

[0021] Furthermore, the present invention provides an all-solid-state battery comprising a solid electrolyte interface (SEI) membrane, the solid electrolyte interface membrane comprising the carbon / silicon polymer composite as described above.

[0022] Furthermore, the present invention provides a lithium-ion battery comprising the negative electrode material as described above.

[0023] The carbon / silicon polymer composite according to an example of the present invention has excellent uniformity of polymer film thickness. The polymer film has almost no effect on conductivity and lithium-ion conductivity. Therefore, when used as a negative electrode material, it can serve as a stable solid electrolyte interface layer while maintaining high specific power and coulombic efficiency, thereby suppressing the reduction of battery performance and life. Simple Explanation of the Diagram

[0024] Figure 1 is a simplified illustration of a process for forming a polymer film on a carbon-silicon composite by initiation chemical vapor deposition (iCVD) according to an example of the present invention.

[0025] Figure 2 is a schematic diagram of a carbon / silicon polymer composite according to an embodiment of the present invention.

[0026] Figure 3 shows the X-ray photoelectron spectroscopy (XPS) analysis results of the carbon-silicon composite of Comparative Example 1 (part (a) of Figure 3) and the carbon / silicon polymer composites of Examples 1 to 4 (parts (b) to (e) of Figure 3).

[0027] Figure 4 is a transmission electron microscope (TEM) image of the carbon-silicon composite of Comparative Example 1 (part (a) of Figure 4) and the carbon / silicon polymer composites of Examples 1, 2 and 5 (parts (b), (c) and (d) of Figure 4).

[0028] Figure 5 is a graph showing the electrochemical evaluation results (charge-discharge efficiency, ICE, and capacity retention) of the carbon / silicon polymer composites of Examples 1 to 6 and the carbon-silicon composite of Comparative Example 1 according to the present invention. Implementation

[0029] This invention is not limited to the contents disclosed below. It can be modified in various forms as long as the purpose of the invention is not changed.

[0030] Unless otherwise specified, "including" in this specification means that other constituent elements may also be included.

[0031] Unless otherwise stated, all figures and expressions relating to the amounts of components, reaction conditions, etc., described in this specification shall be understood to be modified in all cases by the term "about".

[0032] In this specification, the description of one constituent element forming or being connected or combined with another constituent element includes situations where these constituent elements are directly or indirectly formed, connected or combined with each other through the intervention of other constituent elements.

[0033] The present invention will now be described in further detail. Carbon / silicon polymer composite

[0034] As shown in FIG2, according to an embodiment of the present invention, a carbon / silicon polymer composite 10 is provided, comprising: a carbon-silicon composite including a porous carbon support 11 and silicon 12 disposed on the surface and inside the pores of the porous carbon support 11; and a polymer film 13 disposed on the surface of the porous carbon support 11, inside the pores, and on the surface of the silicon 12.

[0035] The constituent elements of a carbon / silicon-polymer composite 10 according to an example of the present invention will now be described. Porous carbon support

[0036] The carbon / silicon polymer composite 10 according to an example of the present invention comprises a porous carbon support 11.

[0037] In the porous carbon support 11, based on the total pore volume, the volume ratio of mesopores with a pore size of 2-50 nm can be 10-80%, preferably 30-60%, and more preferably 40-50%. When the volume ratio of mesopores in the porous carbon support is less than 10%, due to excessive micropores, a relatively large amount of silicon and polymers may form on the outside of the particles. When the volume ratio of mesopores in the porous carbon support exceeds 80%, due to insufficient particle hardness, there is a risk of electrode structure collapse when using it to prepare electrodes.

[0038] Furthermore, the porous carbon support 11 may have a BET specific surface area of ​​300-3000 m² / g. Preferably, the porous carbon support 11 may have a BET specific surface area of ​​300-1500 m² / g, and more preferably, it may have a BET specific surface area of ​​500-1500 m² / g. When the BET specific surface area of ​​the porous carbon support is less than 300 m² / g, there may be a lack of effective pores due to the excessive number of macropores. When the BET specific surface area of ​​the porous carbon support exceeds 3000 m² / g, there may be a large amount of silicon and polymer deposited on the outside of the particles due to the large number of micropores.

[0039] Furthermore, the porous carbon support 11 may have a tap density of 0.05~0.5 g / mL. Preferably, the porous carbon support 11 may have a tap density of 0.05~0.3 g / mL, more preferably, it may have a tap density of 0.1~0.3 g / mL. When the tap density of the porous carbon support is less than 0.05 g / mL, process control may be difficult during silicon source deposition and polymer film formation, leading to a decrease in yield. When the tap density of the porous carbon support exceeds 0.5 g / mL, uniform coating may be difficult during silicon source deposition and polymer film formation.

[0040] Furthermore, the porous carbon support 11 can have an average particle size of 1 to 20 μm. Preferably, the porous carbon support 11 can have an average particle size of 3 to 20 μm, and more preferably, it can have an average particle size of 3 to 10 μm. When the average particle size of the porous carbon support is less than 1 μm, the silicon source, the monomer used to form the polymer film, and the initiator cannot fully penetrate into the pores and are only largely deposited / adsorbed on the outside of the particles. When the average particle size of the porous carbon support exceeds 20 μm, silicon and polymer are difficult to form sufficiently in the pores.

[0041] The carbon / silicon polymer composite 10 according to an example of the present invention includes a porous carbon support 11 having the above-described properties, thereby providing excellent conductivity when the carbon / silicon polymer composite 10 is used as a negative electrode material, and reducing stress caused by the volume expansion of silicon. Silicon

[0042] The carbon / silicon polymer composite 10 according to an example of the present invention includes silicon 12 disposed on the surface and inside the pores of the porous carbon support 11.

[0043] In the carbon / silicon polymer composite 10 according to the present invention, the porous carbon support 11 and silicon 12 are arranged as described above. The negative electrode material prepared from the carbon / silicon polymer composite 10 according to the present invention has high capacitance and can minimize the effects caused by the volume expansion of silicon.

[0044] At this time, the silicon 12 serves to charge the lithium, so when the carbon / silicon polymer composite 10 according to an example of the present invention is used as a negative electrode material, the silicon can be used as the main negative electrode material.

[0045] The silicon 12 can be crystalline or amorphous, preferably amorphous or a similar phase. When the silicon 12 is crystalline, the smaller the crystal size, the denser the composite can be obtained, thus enhancing the strength of the matrix and preventing cracking. Therefore, the initial efficiency or cycle life characteristics of the secondary battery can be improved. On the other hand, when the silicon 12 is amorphous or a similar phase, the expansion or contraction of the secondary battery during charging and discharging is smaller, and battery performance such as capacity characteristics can be improved.

[0046] The particle size of the silicon can be selected in such a way that the carbon / silicon polymer composite according to an example of the invention is suitable for use as a negative electrode material. Specifically, the average size of the silicon particles can be from 10 nm to 50 μm, preferably from 10 nm to 25 μm. Since the silicon meets the range of average particle size, it is more advantageous to achieve the objectives of the invention.

[0047] On the other hand, in the total weight of the carbon / silicon polymer composite 10 according to the present invention, silicon 12 may account for 5 to 80% by weight, preferably 10 to 50% by weight. If the silicon content in the total weight of the carbon / silicon polymer composite is less than 5% by weight, the capacitance may decrease. When the silicon content exceeds 80% by weight, the problem caused by the volume expansion of silicon during charging and discharging cannot be solved, which may cause structural damage to the negative electrode material and reduce the loop characteristics.

[0048] The silicon 12 may further include silicon oxide compounds. Silicon oxide compounds can be represented by the general formula SiOx (0.5 ≤ x ≤ 2). When x is less than 0.5, the expansion and contraction during charging and discharging of the secondary battery increases, potentially deteriorating its lifespan characteristics. When x exceeds 2, the amount of inert oxide increases, and the initial efficiency of the secondary battery may decrease.

[0049] Based on the total weight of silicon, the content of silicon oxide compounds in the silicon can be less than 50% by weight. When the content of silicon oxide compounds in the silicon exceeds 50% by weight, the initial efficiency of the secondary battery may decrease. polymer films

[0050] The carbon / silicon polymer composite 10 according to an example of the present invention includes a polymer film 13 disposed on the surface of the porous carbon support 11, inside the pores, and on the surface of the silicon 12.

[0051] In the carbon / silicon polymer composite according to an example of the invention, the polymer film on the carbon-silicon composite is formed by initiator-based chemical vapor deposition (iCVD) as described later.

[0052] The polymer film is formed by iCVD, and its material type is not particularly limited as long as it has almost no impact on the conductivity of the negative electrode material and the lithium-ion conductivity. Specifically, the polymer film can be polymerized or copolymerized from at least one vinyl or acrylate monomer containing at least one of siloxane, amine, fluorine, glycidyl, and aromatic hydrocarbon groups.

[0053] In a specific embodiment of the present invention, the polymer film may be selected from 4-vinyl pyridine (4VP), 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane, 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluorodecyl isobutylene acid. methacrylate (PFDMA), 1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane (V4D4), 1,3,5-trivinyl-1,3,5-trimethylcyclotrisiloxane (V4D4) 3D3), hexavinyldisiloxane (HVDS), glycidyl methacrylate (GMA), divinylbenzene (DVB), diethylene glycol divinyl ether, diethylene glycol diacrylate (DEGDA), ethylene glycol dimethacrylate, dimethylaminoethyl methacrylate, methacrylic acid, and 1,3-divinyl-1,1,3,3-tetramethyl-disiloxane, 1H,1H,2H,2H - Perfluorodecyl acrylate (PFDA), perfluorodecyl methacrylate, dodecafluoroheptyl acrylate, pentafluorophenyl methacrylate, 3,3,4,4,5,5,6,6,7,7,8,8,9,9,9-pentadecafluorononyl acrylate, 2-methyl-3,3,4,4,5,5,6,6,7,7,8,8,9,9,9-pentadecafluorononyl acrylate, 3,3,4,4,5,5,6,6,7,7,8,8,8-tetrafluorooctyl acrylate, 2-methyl-3,3,4,4,5,5,6,6 7,7,8,8,8-Tetrafluorooctyl acrylate, 3,3,4,4,5,5,6,6,7,7,7-Undecylfluoroheptyl acrylate, 2-Methyl-3,3,4,4,5,5,6,6,7,7,7-Undecylfluoroheptyl acrylate, 3,3,4,4,5,5,6,6,6-Nonfluorohexyl acrylate, 2-Methyl-3,3,4,4,5,5,6,6,6-Nonfluorohexyl acrylate, 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,11-Ninedecylfluoroundecyl acrylate, 2-Methyl-3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,11-Ninedecylfluoroundecyl acrylate, 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,12-Ticosicofluorododecyl acrylate, 2-methyl 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,12-teicosicofluorododecyl acrylate, 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,13,13,13-teicosicofluorotridecyl acrylate, 2-methyl-3,3, 4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,13,13,13-Ticosicotridecyl acrylate, 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,13,13,14,14,14-Ticosicotetradecyl acrylate, 2-methyl A thin film polymerized from at least one monomer selected from the group consisting of 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,13,13,14,14,14-tetrafluorotetradecyl acrylate, dimethylaminoethyl methacrylate, dimethylaminoethyl acrylate, diethylaminoethyl methacrylate, and diethylaminoethyl acrylate.

[0054] In a preferred embodiment of the present invention, the polymer film may be a film polymerized from at least one monomer selected from the group consisting of 1H,1H,2H,2H-perfluorodecyl acrylate, N,N-dimethylvinylbenzene, divinylbenzene, glycidyl methacrylate, 1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane, 1,3,5-trivinyl-1,3,5-trimethylcyclotrisiloxane, and hexavinyldisiloxane, but is not particularly limited thereto.

[0055] In a specific embodiment of the present invention, the thickness of the polymer film can be 1~450 nm, preferably 1~200 nm, more preferably 1~100 nm, and even more preferably 1~50 nm. When the thickness of the polymer film is within this range, it has almost no effect on the conductivity and lithium-ion conductivity of the negative electrode material, and serves as a stable solid electrolyte interface layer between silicon and the electrolyte, thereby suppressing the reduction of battery life.

[0056] On the other hand, in the total weight of the carbon / silicon polymer composite 10 according to the present invention, the polymer film may account for 1 to 30% by weight, preferably 1 to 20% by weight. If the polymer film accounts for less than 1% by weight in the total weight of the carbon / silicon polymer composite, it may not be able to serve as a stable solid electrolyte interface layer; if the polymer film accounts for more than 30% by weight, it may instead become a factor that hinders the reaction on the silicon surface. Preparation method of carbon / silicon polymer composite

[0057] According to an example of the present invention, a carbon / silicon polymer composite is prepared by a method comprising: step (1) preparing a carbon-silicon composite by forming silicon on the surface and inside the pores of a porous carbon support; and step (2) forming a polymer film on the surface of the porous carbon support, inside the pores, and on the surface of the silicon of the carbon-silicon composite by initiator-based chemical vapor deposition (iCVD) to prepare the carbon / silicon polymer composite.

[0058] The following describes the steps of a method for preparing a carbon-silicon / polymer composite according to an example of the present invention. Step (1)

[0059] In step (1) above, carbon-silicon composites are prepared by forming silicon on the surface and inside the pores of a porous carbon support.

[0060] In a specific example of the invention, the step of forming silicon on the surface and inside the pores of the porous carbon support can be performed using apparatus (e.g., a rotary kiln) and methods (e.g., chemical vapor deposition; CVD) known in the art to which this invention pertains. Specifically, a silicon source can be supplied to the porous carbon support and CVD can be performed, thereby forming silicon on the surface and inside the pores of the porous carbon support.

[0061] In a specific example of the present invention, the silicon source may include at least one selected from silane (SiH4), dichlorosilane (SiH2Cl2), silicon tetrafluoride (SiF4), silicon tetrachloride (SiCl4), methylsilane (CH3SiH3), and disilane (Si2H6), but is not particularly limited thereto.

[0062] CVD with the silicon source can be performed at temperatures ranging from 300 to 700°C. For example, CVD with the silicon source can be performed at temperatures of 400–600°C, 400–500°C, or 400–450°C, but is not particularly limited to these ranges. Furthermore, CVD can be performed at atmospheric pressure, and, if necessary, at a low vacuum of approximately 10 Torr. Additionally, the deposition can be performed, for example, in a silane (SiH4) gas atmosphere ranging from 50 sccm to 500 sccm. Step (2)

[0063] In step (2) above, a polymer film is formed on the surface of the porous carbon support, inside the pores, and on the surface of the silicon in the carbon-silicon composite by initiator-based chemical vapor deposition (iCVD) to prepare a carbon / silicon polymer composite.

[0064] At this point, initiated chemical vapor deposition (iCVD) refers to a process that polymerizes monomers by decomposing a vapor-phase initiator into radicals. In iCVD, energy is supplied by a heat source such as a heated filament or UV light to induce the deposition of a polymer film. Therefore, it appears not significantly different from existing inorganic thin-film deposition CVD processes. However, in iCVD, the initiator is activated at a low temperature range of 135–350°C (preferably 140–340°C). Furthermore, the surface temperature of the carbon-silicon composite on which the polymer film is deposited is maintained in the range of 10–50°C, preferably in the range of 13–45°C. Due to this low surface temperature, iCVD can be effectively used to deposit polymer films on multiple substrates with low mechanical or chemical impact. Moreover, the iCVD process is carried out under a vacuum range of 50–1000 mTorr, preferably in the range of 60–900 mTorr, thus eliminating the need for high-vacuum equipment.

[0065] On the other hand, according to an embodiment of the present invention, step (2) may include: step (2-1), supplying a carbon-silicon composite into a reactor; step (2-2), supplying a monomer and an initiator into the reactor supplying the carbon-silicon composite; and step (3), polymerizing the monomer by activating the initiator, thereby forming a polymer film on the surface of the porous carbon support of the carbon-silicon composite, inside the pores and on the surface of the silicon.

[0066] Figure 1 is a simplified illustration of the process of forming a polymer film on the surface of a porous carbon support, inside the pores, and on the surface of silicon by initiated chemical vapor deposition (iCVD) according to an example of the present invention. Referring to Figure 1, a method for preparing a carbon / silicon polymer composite according to an example of the present invention is explained. Step (2-1)

[0067] In step (2-1) above, a carbon-silicon composite is supplied into the reactor.

[0068] The reactor used in the method for preparing the carbon / silicon polymer composite according to an example of the present invention is not particularly limited in structure, as long as it is a reactor capable of forming a polymer film on the carbon-silicon composite using initiated chemical vapor deposition (iCVD) as described later.

[0069] In a specific example of the present invention, the reactor 1000 may include a cavity 100, a mounting part 200, an inlet 300, an outlet 400, and a heating part 500.

[0070] The carbon-silicon composite can be disposed in the mounting portion 200, which is located at the lower end of the cavity 100 of the reactor 1000. The shape, size, and material of the mounting portion are not particularly limited as long as it can accommodate the carbon-silicon composite. Specifically, the mounting portion can be flat, allowing the carbon-silicon composite to be arranged with minimal overlap. More specifically, a silicon substrate (wafer) can be used as the mounting portion for accommodating the carbon-silicon composite, but is not particularly limited thereto.

[0071] The mounting portion can be connected to a position changing means (not shown) capable of changing the position of the carbon-silicon composite. The position changing means may, for example, vibrate or move the mounting portion, which is a silicon substrate, so that the position of the carbon-silicon composite disposed on the silicon substrate changes or rotates, thereby causing a polymer film to be uniformly formed on the carbon-silicon composite in steps (2-3) described later, but is not particularly limited thereto. Step (2-2)

[0072] In step (2-2) above, monomers and initiators are supplied to the reactor.

[0073] At this time, the monomer M and the initiator I are vaporized and supplied to the cavity 100 through the inlet 300 of the reactor 1000.

[0074] The monomer M is a volatile substance that can be initiated by initiator I to form a polymer. Details of the monomer are as described in the section on carbon / silicon polymer composites above.

[0075] The initiator I is a substance that decomposes through heat or light to form free radicals. Its type is not particularly limited as long as it can initiate the formation of the monomer into a polymer. Preferably, the initiator can be a peroxide. Specifically, the initiator may include at least one selected from the group consisting of di-tert-butyl peroxide, tert-butyl peroxide, benzoyl peroxide, methyl ethyl ketone peroxide, lauryl peroxide, and benzophenone, but is not particularly limited thereto. Most preferably, the initiator is di-tert-butyl peroxide.

[0076] At this point, the monomer flow rate in the reactor can be from 0.1 sccm to 10 sccm. Specifically, the monomer flow rate can be above 0.1 sccm, above 0.1 sccm and below 10 sccm, below 5 sccm, or below 4 sccm.

[0077] Furthermore, the initiator flow rate in the reactor can be from 0.1 sccm to 5 sccm. Specifically, the initiator flow rate can be above 0.1 sccm and below 5 sccm, below 3 sccm, or below 2 sccm. Steps (2-3)

[0078] In steps (2-3) above, the monomer is polymerized by activating the initiator, thereby forming a polymer film on the surface of the porous carbon support, inside the pores, and on the surface of the silicon in the carbon-silicon composite.

[0079] First, the initiator I, supplied in a vaporized state to the cavity 100 of the reactor 1000, comes into contact with the heating element 500 and is activated to form free radicals (I*). The heating element may be, for example, a plurality of electrically heated filaments, but is not particularly limited thereto. The temperature range of the heating element is not limited as long as the initiator can be decomposed and activated, but is preferably in the range of 135–350°C, more preferably in the range of 140–340°C, which may be advantageous in preventing changes in the properties of the reactants.

[0080] The free radicals (I*) generated by the initiator and the monomers M move to the lower part of the cavity and adsorb onto the surface of the porous carbon support, the interior of the pores, and the surface of the silicon of the carbon-silicon composite housed in the mounting part 200. The monomers adsorbed on the surface of the porous carbon support, the interior of the pores, and the surface of the silicon of the carbon-silicon composite are initiated (M*) by the free radicals (I*) and polymerize to form a polymer film on the surface of the porous carbon support, the interior of the pores, and the surface of the silicon of the carbon-silicon composite.

[0081] The remaining gas-phase initiator and monomers after use in the reaction of steps (2-3) above are discharged to the outside of the reactor through outlet 400.

[0082] In steps (2-3) above, to increase the adsorption rate of the monomers and free radicals, it is preferable to maintain the temperature of the carbon-silicon composite surface at a low level. Specifically, the temperature range of the carbon / silicon composite surface can be 10~50°C, preferably 13~45°C, but is not limited to this range. To maintain the temperature of the carbon / silicon composite surface within the above range, the reactor 1000 may also include a cooling section (not shown) disposed below the mounting section 200. As long as the temperature of the carbon / silicon composite surface can be controlled within the above range, the cooling method, structure, etc. of the cooling section (not shown) are not particularly limited.

[0083] Steps (2-3) above can be performed under a vacuum of 50 to 1000 mTorr, preferably 60 to 900 mTorr. These vacuum ranges can be provided by a simple rotary pump instead of a high-vacuum pump.

[0084] Furthermore, the reaction in steps (2-3) can proceed for 10 minutes to 6 hours, preferably 30 minutes to 2 hours, but is not limited to this. However, as long as the reaction time meets the above time range, a polymer film of the target thickness can be uniformly formed.

[0085] The physical properties of the polymer film formed in steps (2-3) above can be easily adjusted by controlling the process variables of iCVD. That is, the molecular weight, thickness, composition, and deposition rate of the polymer film can be easily adjusted by controlling the pressure and temperature in the chamber, the reaction time, the flow rate of the initiator and monomer, the temperature of the heating section, and the temperature of the carbon-silicon composite surface and pores. Previous steps

[0086] On the other hand, according to an embodiment of the present invention, the method for preparing the carbon / silicon polymer composite may further include, before step (1): step (a), synthesizing asphalt by thermal decomposition and polycondensation of petroleum-based raw materials; step (b), curing and granulating the asphalt to obtain granular asphalt, or curing, granulating and pulverizing the asphalt to obtain powdered asphalt; step (c), stabilizing the granular asphalt or powdered asphalt; step (d), carbonizing the stabilized asphalt to obtain carbides; and step (e), initiating the carbides to obtain a porous carbon support.

[0087] In step (a), petroleum-based feedstocks can be thermally decomposed and polycondensed to synthesize asphalt.

[0088] In a specific embodiment of the present invention, the petroleum-based feedstock may include at least one selected from the group consisting of thermally decomposed fuel oil (PFO), naphtha cracking residue (NCB), ethylene cracker bottom oil (EBO), vacuum residue (VR), deasphalted oil (DAO), atmospheric residue (AR), fluidized bed catalytic cracking decant oil (RFCC-DO), residue fluid catalytic cracking decant oil (RFCC-DO), and heavy aromatic oil. In a preferred embodiment of the present invention, the petroleum-based feedstock may include thermally decomposed fuel oil.

[0089] In a specific example of the present invention, the petroleum-based feedstock may contain 10 to 90% by weight of aromatic compounds. Preferably, the petroleum-based feedstock may contain 20 to 80% by weight of aromatic compounds, and more preferably, 30 to 70% by weight. When the content of aromatic compounds in the petroleum-based feedstock meets the above range, a porous carbon support with controlled pore characteristics can be obtained even without separately pulverizing the solid asphalt particles described later during stabilization, carbonization, and startup.

[0090] In a specific example of the invention, the aromatic compound may be a compound having 1 to 4 aromatic rings. Specifically, the aromatic compound may include at least one selected from the group consisting of substituted or unsubstituted benzene, naphthalene, phenanthrene, indene, biphenyl, anthracene, tetrahydronaphthalene, and fluorene. In this case, even without separately pulverizing the solid pitch particles described later, a porous carbon support with controlled pore characteristics can be obtained through stabilization, carbonization, and initiation.

[0091] In a specific embodiment of the present invention, the thermal decomposition and polycondensation of petroleum-based raw materials can be carried out at a temperature of 350-500°C. In a preferred embodiment of the present invention, the thermal decomposition and polycondensation of petroleum-based raw materials can be carried out at a temperature of 400-500°C. In a more preferred embodiment of the present invention, the thermal decomposition and polycondensation of petroleum-based raw materials can be carried out at a temperature of 430-470°C. When the thermal decomposition and polycondensation temperature of the petroleum-based raw materials is 350-500°C, asphalt containing a relatively low molecular weight component can be prepared. During the initiation process of step (e) described later, the component with a relatively low molecular weight vaporizes first, thereby allowing sufficient mesopores to form in the carbon support. If the thermal decomposition and polycondensation temperature of the petroleum-based raw materials is less than 350°C, it is difficult to prepare solid asphalt at room temperature. When the temperature exceeds 500°C, the asphalt contains a relatively high molecular weight component, making it difficult to prepare a carbon support with mesopores.

[0092] In a specific embodiment of the invention, the thermal decomposition and polycondensation of petroleum-based feedstocks can be carried out in an atmosphere of an oxidizing gas, an inert gas, or a mixture thereof. In a preferred embodiment of the invention, the oxidizing gas can be oxygen, ozone, or a combination thereof, the inert gas can be nitrogen, helium, neon, argon, or a combination thereof, and the mixture thereof can be air, but is not particularly limited thereto.

[0093] Using oxidizing gases during the thermal decomposition and polycondensation of petroleum-based feedstocks allows for the production of asphalt with a high softening point, but this process is difficult to sustain at high temperatures. Using inert gases allows for thermal decomposition and polycondensation at high temperatures, but it is also difficult to produce asphalt with a relatively high softening point. However, using a mixture of oxidizing and inert gases allows for thermal decomposition and polycondensation at relatively high temperatures, thus enabling the production of asphalt with a relatively high softening point.

[0094] In a specific embodiment of the present invention, the gas is supplied at a flow rate of 10 to 800 mL / min during the thermal decomposition and polycondensation of petroleum-based feedstocks. In a preferred embodiment of the present invention, the gas is supplied at a flow rate of 100 to 500 mL / min during the thermal decomposition and polycondensation of petroleum-based feedstocks. When the flow rate of the gas is less than 10 mL / min, the yield of asphalt increases, but the low molecular weight components increase excessively, which is detrimental to subsequent processes (e.g., stabilization). When the flow rate of the gas exceeds 800 mL / min, the yield of asphalt may decrease.

[0095] In a specific embodiment of the present invention, the thermal decomposition and polycondensation of petroleum-based raw materials can be carried out for 1 to 10 hours. In a preferred embodiment of the present invention, the thermal decomposition and polycondensation of petroleum-based raw materials can be carried out for 2 to 8 hours. In a more preferred embodiment of the present invention, the thermal decomposition and polycondensation of petroleum-based raw materials can be carried out for 2 to 7 hours. When the thermal decomposition and polycondensation time of petroleum-based raw materials is less than 1 hour, it is difficult to prepare asphalt with a high softening point. When the thermal decomposition and polycondensation time of petroleum-based raw materials exceeds 10 hours, excessive production of quinoline-insoluble components may occur.

[0096] In a specific example of the invention, the thermal decomposition and polycondensation of petroleum-based feedstocks can be carried out under stirring. There are no particular limitations on the stirring conditions for the petroleum-based feedstocks, but a stirrer rotating at, for example, 10 to 500 rpm can be used.

[0097] In a specific example of the present invention, the asphalt synthesized in step (a) may have a softening point of 200-350°C. In a preferred example of the present invention, the asphalt may have a softening point of 200-330°C. In a more preferred example of the present invention, the asphalt may have a softening point of 200-300°C. The asphalt prepared according to the present invention has a high softening point, which facilitates the stabilization process when used as a precursor for preparing carbon supports, and allows for high yields after carbonization and start-up.

[0098] In a specific example of the present invention, the yield of the asphalt synthesized in step (a) may be 10-50% by weight. In a preferred example of the present invention, the yield of the asphalt may be 10-40% by weight. In a more preferred example of the present invention, the yield of the asphalt may be 20-30% by weight.

[0099] In a specific example of the present invention, a pretreatment step of the petroleum-based raw material may be performed before step (a) above. This pretreatment step removes low-boiling-point components from the petroleum-based raw material, thereby enabling the preparation of asphalt with a higher softening point.

[0100] In a specific example of the present invention, the pretreatment step may be carried out at a temperature equal to or lower than the thermal decomposition and polycondensation temperature of the petroleum-based raw material in step (a), but is not particularly limited to this condition. Specifically, the pretreatment step may be carried out at a temperature of 250 to 450°C, preferably 250 to 400°C, and more preferably 300 to 400°C.

[0101] In a specific example of the present invention, the pretreatment step may take a time equal to or shorter than the thermal decomposition and polycondensation time of the petroleum-based feedstock in step (a), but is not particularly limited to this condition. Specifically, the pretreatment step may take 1 to 8 hours, preferably 1 to 6 hours, and more preferably 1 to 5 hours.

[0102] Furthermore, in step (b), granular asphalt is obtained by curing and granulating the asphalt, or powdered asphalt is obtained by curing, granulating, and pulverizing the asphalt.

[0103] First, in the case of granular asphalt, the asphalt (liquid) obtained in step (a) is solidified, for example, by extrusion and cooling, and granulated to the desired size to obtain solid asphalt particles (granular asphalt). The process of extruding, cooling, and granulating liquid asphalt to obtain solid asphalt particles can be carried out using commercially available equipment. For example, this process can be carried out using a twin-belt cooler and flake machine from IPCO, but is not particularly limited to this equipment.

[0104] The asphalt particles (granular asphalt) obtained in step (b) have an average particle size of 1 to 30 mm, preferably 5 to 25 mm. When the average particle size of the asphalt particles (granular asphalt) is within this range, a porous carbon support can be prepared by stabilization, carbonization, and initiation as described later, without the need for separate pulverization of the asphalt particles (granular asphalt).

[0105] Furthermore, in the case of powdered asphalt, the asphalt particles (granular asphalt) can be further crushed or pulverized, and classified. Crushing or pulverizing further micronizes the asphalt particles (granular asphalt), and classification ensures a uniform distribution of fineness among the particles. Classification can be performed using dry classification, wet classification, or grading using sieves. Through crushing or pulverizing and classification, powdered asphalt with an average particle size of 50-500 μm can be obtained.

[0106] Furthermore, in step (c), a step of stabilizing the granular or powdered asphalt may be performed.

[0107] First, the granular or powdered asphalt obtained in step (b) is subjected to primary oxidation to stabilize the carbon structure of the asphalt.

[0108] In a specific embodiment of the invention, the stabilization of asphalt can be carried out in an oxidizing gas atmosphere. In a preferred embodiment of the invention, the stabilization of asphalt can be carried out in an air atmosphere, but is not particularly limited thereto.

[0109] In a specific example of the present invention, the stabilization of asphalt can be carried out at a temperature of 100~500°C, preferably 150~300°C. When the asphalt is stabilized at this temperature, the carbon structure in the granular or powdered asphalt changes from thermoplastic to thermosetting, and this structure can be stably maintained during the subsequent carbonization process. At this time, the heating rate can be 2~10°C / minute. If the heating rate is too slow, the production performance is poor; if the heating rate is too fast, it may be difficult to achieve uniform stabilization.

[0110] In a specific embodiment of the invention, the stabilization can be carried out under a pressure of 0.1 to 10 bar, preferably under a pressure of 0.5 to 5 bar. When the stabilization is carried out under this pressure, its structure can be sufficiently stabilized to the carbon inside the granular or powdery asphalt.

[0111] In a specific embodiment of the invention, the stabilization can be carried out at a rate of 0.1 to 500 mL / min, preferably at an oxidizing gas rate of 1 to 300 mL / min, and more preferably at an air flow rate. When the stabilization is carried out at this oxidizing gas flow rate, the structure can be sufficiently stabilized to the carbon inside the granular or powdered asphalt.

[0112] In a specific example of the invention, the stabilization process can be carried out for 1 to 10 hours, preferably 2 to 8 hours. During this period of stabilization, the structure can be sufficiently stabilized to the carbon inside the granular or powdery asphalt.

[0113] Furthermore, in step (d), carbides are obtained by carbonizing the stable asphalt. By carbonizing the stable asphalt, other functional groups contained in the asphalt can be removed, and carbides formed essentially of pure carbon can be obtained.

[0114] In a specific embodiment of the invention, the carbonization can be carried out under an inert gas atmosphere. In a preferred embodiment of the invention, the carbonization can be carried out under a nitrogen or argon atmosphere, but is not particularly limited thereto.

[0115] In a specific embodiment of the invention, the carbonization can be carried out at a temperature exceeding 700°C but below 1000°C, preferably at a temperature of 800-900°C. When the carbonization temperature is below this range, the carbonization may not proceed sufficiently, and when the carbonization temperature is above this range, the carbonization yield may decrease.

[0116] In a specific embodiment of the invention, the carbonization can be carried out under an inert gas flow rate of 0.1 to 30 mL / min (preferably 0.1 to 10 mL / min), and more preferably, under a nitrogen flow rate. When the carbonization is carried out under this inert gas flow rate, the stable asphalt can be fully carbonized.

[0117] In a specific example of the invention, the carbonization can be carried out for 0.5 to 5 hours, preferably 1 to 3 hours. When the carbonization is carried out during this period, the stable asphalt can be fully carbonized.

[0118] Furthermore, in step (e), a porous carbon support is obtained by initiating the carbide (carbonized bitumen). The initiation of the carbide creates pores within it, thereby obtaining a porous carbon support.

[0119] In a specific embodiment of the invention, the initiation of the carbide can be carried out in an oxidizing gas atmosphere. In a preferred embodiment of the invention, the initiation of the carbide can be carried out in a water vapor atmosphere, but is not particularly limited thereto.

[0120] In a specific embodiment of the invention, the initiation of the carbide can be carried out at a temperature exceeding 700°C and below 1000°C, preferably at a temperature of 800-900°C. When the carbide is initiated at this temperature, a porous carbon support with sufficiently formed micropores and mesopores can be obtained.

[0121] In a specific example of the present invention, the initiation of the carbide can be carried out under a pressure of 0.1 to 10 bar, preferably under a pressure of 0.1 to 5 bar. When the carbide is initiated under this pressure condition, a porous carbon support with sufficient micropores and mesopores can be obtained.

[0122] In a specific example of the present invention, the initiation of the carbide can be carried out under a flow rate of 0.1 to 100 mL / min (preferably 0.1 to 50 mL / min) of oxidizing gas, and more preferably, under a flow rate of water vapor. When the initiation of the carbide is carried out under this flow rate of oxidizing gas, a porous carbon support with sufficiently formed micropores and mesopores can be obtained.

[0123] In a specific example of the present invention, the initiation of the carbide can be carried out for 0.5 to 5 hours, preferably 1 to 3 hours. When the initiation of the carbide is carried out during this period, a porous carbon support with sufficient micropores and mesopores can be obtained.

[0124] In a specific embodiment of the present invention, the stabilization, carbonization, and startup steps (c) to (e) described above can be performed in a microwave-heated furnace. In a preferred embodiment of the present invention, the stabilization, carbonization, and startup steps (c) to (e) described above can all be performed in a microwave-heated furnace. A microwave-heated furnace can increase the temperature of the asphalt itself without increasing the external temperature of the asphalt, which is therefore preferred, but not particularly limiting.

[0125] In a specific embodiment of the present invention, steps (c) to (e) can be performed continuously in one apparatus. In a preferred embodiment of the present invention, steps (c) to (e) can be performed continuously in a rotary furnace, but are not particularly limited to this apparatus. When steps (c) to (e) are performed continuously in one apparatus, process optimization can be achieved.

[0126] In a specific example of the present invention, the porous carbon support obtained in step (e) can be further crushed or pulverized, and classified. Crushing or pulverizing can further micronize the porous carbon support, and classification can make the particle size distribution of the porous carbon support uniform. Classification can be performed using dry classification, wet classification, or classification using sieves, etc. Through crushing or pulverizing and classification, porous carbon support powder with an average particle size of 1-20 μm, a BET specific surface area of ​​300-3000 m² / g, and a tap density of 0.05-0.5 g / mL can be obtained. Furthermore, based on the total pore volume, the volume ratio of mesopores (pore size 2-50 nm) in the porous carbon support powder is 10-80%.

[0127] On the other hand, in step (b) above, when stabilizing, carbonizing and starting the granular asphalt to obtain a porous carbon support without further pulverizing the asphalt, the carbon support may be pulverized (or further classified) to give it an average particle size of 1 to 20 μm, but is not limited thereto.

[0128] In the method for preparing the carbon / silicon polymer composite according to an example of the present invention, the obtained carbon / silicon polymer composite may be crushed or pulverized, and classified. Classification can make the particle size distribution of the composite uniform. Classification may be performed using dry classification, wet classification, or classification using sieves, etc. Anode material

[0129] According to another embodiment of the invention, a negative electrode material comprising the carbon / silicon polymer composite is provided.

[0130] In addition to the carbon / silicon polymer composite, the anode material according to embodiments of the present invention may also include a carbon-based anode material, specifically, a graphite-based anode material. For example, the anode material can be obtained by mixing the carbon / silicon polymer composite according to embodiments of the present invention with a carbon-based anode material, for example, by mixing a graphite-based anode material.

[0131] The carbon-based anode material may include, for example, at least one selected from the group consisting of natural graphite, artificial graphite, soft carbon, hard carbon, meso carbon, carbon fiber, carbon nanotubes, thermally decomposed carbon, coke, sintered organic polymer compounds, and carbon black, but is not particularly limited thereto.

[0132] Relative to the total weight of the negative electrode material, the content of carbon-based negative electrode material in the negative electrode material of the embodiment of the present invention can be 2 to 80% by weight, preferably 5 to 70% by weight, and more preferably 30 to 70% by weight.

[0133] The negative electrode material according to an example of the present invention can be effectively used in the preparation of secondary batteries, specifically, for the preparation of negative electrodes for lithium secondary batteries and negative electrodes for all-solid-state batteries. Lithium-ion batteries

[0134] According to another embodiment of the present invention, a lithium-ion battery comprising the negative electrode material is provided.

[0135] The lithium-ion battery may include an electrolyte, a positive electrode, a negative electrode, and a separator between the positive and negative electrodes, and the negative electrode material as the negative electrode includes the negative electrode material described above.

[0136] In addition to the negative electrode material of the lithium-ion battery, the negative electrode structure, positive electrode structure, electrolyte structure and separator structure can be any known lithium-ion battery structure, and therefore are not particularly limited in this invention. All-solid-state batteries

[0137] According to another embodiment of the present invention, an all-solid-state battery comprising a solid electrolyte interface (SEI) membrane is provided, the all-solid-state battery comprising the carbon / silicon polymer composite.

[0138] The all-solid-state battery may be an all-solid-state battery comprising a positive electrode, a negative electrode, and a solid electrolyte between the positive electrode and the negative electrode. The negative electrode may include a negative electrode material layer, and at least a portion of the negative electrode material particles in the negative electrode material layer may include a solid electrolyte interface (SEI) film. The solid electrolyte interface film includes the carbon / silicon polymer composite as described above.

[0139] On the other hand, the negative electrode material particles may be carbon-based negative electrode materials. In this case, the content may be the same as that described in the above negative electrode material description, so the relevant description is omitted.

[0140] In addition, apart from the negative electrode material particles and SEI film of the all-solid-state battery, the negative electrode structure, positive electrode structure and solid electrolyte structure can be applied using known all-solid-state battery structures, and therefore are not particularly limited in this invention. [Example]

[0141] The present invention will be further described in detail below through embodiments. These embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. <Preparation Example>

[0142] 300g of petroleum-based residual oil (Yoncheon Naphtha Cracking Center (YNCC), Korea), HTC PFO (thermal decomposition fuel oil)) was added to a reactor equipped with a stirrer. Nitrogen gas was supplied at a flow rate of 100mL / min, and thermal decomposition and polycondensation were carried out at 450°C for 3 hours. During this time, the stirrer was rotated at 200rpm to mix the reactants. The polymerized asphalt was then cured and granulated to obtain solid asphalt particles with an average particle size of 1~30mm.

[0143] The solid asphalt particles obtained above were pulverized to prepare asphalt particles with an average particle size of 200 μm. These particles were then placed in a rotary kiln with three zones and subjected to stabilization, carbonization, and start-up processes sequentially. The conditions for stabilization, carbonization, and start-up are shown in Table 1 below.

[0144] The specific surface area of ​​the carbon support was determined using a Belserp mini II according to ASTM D4820-93. The tap density of the carbon support was determined using a tap density analyzer (manufacturer: Electrolab, model: ETD-1020x) according to ASTM B527. The average particle size of the carbon support was determined using a particle size analyzer (manufacturer: Horiba, Japan, laser particle size analyzer, model: LA-960V2) according to ASTM E112. The results are shown in Table 1. Table 1 step condition Reference Example Stabilization Temperature (°C) 300 Time (hours) 3 atmosphere Air carbonization Temperature (°C) 900 Time (hours) 1 atmosphere Nitrogen start up Temperature (°C) 900 Time (hours) 3 Water vapor flow rate (mL / min) 200 Physical properties of the support Average particle size (μm) 200 Specific surface area (m² / g) 1409.1 Tap density (g / mL) 0.44

[0145] The porous carbon support of the reference example was pulverized using a pulverizer (manufacturer: NETZSCH, Germany), air jet mill, to obtain fine powder of the porous carbon support with an average particle size of 7 μm. Next, 15 g of this fine powder of porous carbon support was placed in a rotary furnace, and silane (SiH4) gas was injected to form a silicon layer on the porous carbon support, thus preparing a carbon-silicon composite. The silicon layer formation conditions and the physical properties of the carbon support after silicon layer formation are shown in Table 2 below. Table 2 step Reference Example Silicon layer formation conditions Batch (g) 15 pressure Atmospheric pressure Temperature (°C) 475 Time (minutes) 120 Physical properties of carbon-silicon composites after silicon layer formation Average particle size (μm) 8.9 Specific surface area (m² / g) 10.4 Tap density (g / mL) 0.6 <Example 1: Preparation of carbon / silicon polymer composite>

[0146] A carbon / silicon polymer composite was prepared using the reactor schematically illustrated in Figure 1. 5 g of the carbon-silicon composite prepared according to the preparation example was uniformly spread on a circular silicon wafer. Vaporized monomers and an initiator were supplied into the reactor chamber through an inlet, causing a polymer film (pDVB) to form on the surface of the porous carbon support, inside the pores, and on the surface of the silicon of the carbon-silicon composite. The average thickness of the formed polymer film was 10 nm. The specific conditions of the materials and processes used in this Example 1 are as follows. - Carbon / silicon polymer composite: Preparation example Monomer: Divinylbenzene (DVB) (Divinylbenzene, Aldrich, technical grade, 80%) -Initiator: Di-tert-butyl peroxide (Aldrich, 98%) -Initiator average supply flow rate: 0.26 sccm - Average supply flow rate per unit: 0.425 sccm -Hot wire temperature: 140℃ -Reaction time: 1 hour - Reactor chamber pressure: 160 mTorr - Surface temperature of reactor mounting section (silicon wafer): 35℃ <Example 2>

[0147] The carbon / silicon polymer composite was prepared using the same method as in Example 1, except that a polymer film (pDMAMS) was formed on the surface of the porous carbon support, inside the pores, and on the surface of the silicon in the carbon-silicon composite by changing the following items. The average thickness of the formed polymer film was 10 nm.

[0148] Monomer: N,N-Dimethylaminomethyl styrene (Manufacturer: Acros, 90%) <Example 3>

[0149] A carbon / silicon polymer composite was prepared using the same method as in Example 1, except that a polymer film (pPFDA) was formed on the surface of the porous carbon support, inside the pores, and on the surface of the silicon in the carbon-silicon composite by changing the following items. The average thickness of the formed polymer film was 10 nm. - Monomer: 1H,1H,2H,2H-perfluorodecyl acrylate (Aldrich, 97%) -Reaction time: 15 minutes - Reactor chamber pressure: 80 mTorr - Surface temperature of reactor mounting section (silicon wafer): 38℃ <Example 4>

[0150] A carbon / silicon polymer composite was prepared using the same method as in Example 1, except that a polymer film (pGMA) was formed on the surface of the porous carbon support, inside the pores, and on the surface of the silicon in the carbon-silicon composite by changing the following items. The average thickness of the formed polymer film was 10 nm. - Monomer: Glycidyl methacrylate (GMA) (Aldrich, 97%) -Reaction time: 2 hours - Reactor chamber pressure: 80 mTorr - Surface temperature of reactor mounting section (silicon wafer): 38℃ <Example 5>

[0151] A carbon / silicon polymer composite was prepared using the same method as in Example 1, except that a polymer film (pDVB) was formed on the surface of the porous carbon support, inside the pores, and on the surface of the silicon in the carbon-silicon composite by changing the following items. The average thickness of the formed polymer film was 1 nm.

[0152] To control the thickness of the polymer film, the reaction time of the iCVD process was controlled to 10 minutes. <Example 6>

[0153] A carbon / silicon polymer composite was prepared using the same method as in Example 1, except that a polymer film (pDVB) was formed on the surface of the porous carbon support, inside the pores, and on the surface of the silicon in the carbon-silicon composite by changing the following items. The average thickness of the formed polymer film was 500 nm.

[0154] To control the thickness of the polymer film, the reaction time of the iCVD process was controlled to 6 hours. <Comparative Example 1>

[0155] A carbon-silicon composite was prepared according to the preparation example. <Experimental Example 1> (1) X-ray photoelectron spectroscopy analysis

[0156] For Examples 1 to 4 and Comparative Example 1, the elements on the particle surface were analyzed by X-ray photoelectron spectroscopy (XPS) (model: Multilab 2000, manufacturer: Thermo Fisher Scientific, USA), and the results are shown in Figure 3.

[0157] As a result, in Comparative Example 1 (part (a) of FIG3) where no polymer film was formed, no fluorine or nitrogen was measured; only oxygen, carbon, and silicon were measured. It was confirmed that the carbon ratio increased during the formation of the pDVB polymer film (Example 1), nitrogen was measured during the formation of the pDMAMS polymer film (Example 2), a considerable amount of fluorine was measured during the formation of the pPFDA polymer film (Example 3), and the carbon ratio increased during the formation of the pGMA polymer film (Example 4). Therefore, it can be seen that the preparation method of the present invention has prepared a carbon / silicon polymer composite in which a polymer film containing carbon, nitrogen, or fluorine is formed on the surface of a porous carbon support, inside the pores, and on the surface of the silicon. (2) Transmission electron microscopy (TEM) image analysis

[0158] Examples 1, 2, 5 and Comparative Example 1 were observed using a transmission electron microscope (TEM) (Figure 4).

[0159] As a result, no additional polymer film was observed in Comparative Example 1 (part (a) of FIG. 4), where no polymer film was formed; in Examples 1 (part (b) of FIG. 4) and 2 (part (c) of FIG. 4), a polymer film with a thickness of 10 nm was observed; and in Example 5 (part (d) of FIG. 4), a polymer film with a thickness of 1-2 nm was observed. Therefore, it can be confirmed that, according to the preparation method of the present invention, a polymer film can be well formed on the surface of the porous carbon support, inside the pores, and on the surface of the silicon, and the formed polymer film has a uniform thickness. <Experimental Example 2: Electrochemical Evaluation>

[0160] Half-button batteries were prepared using the composites from Examples 1 to 6 and Comparative Example 1, and electrochemical evaluations were performed. The preparation conditions of the half-button batteries are shown in Table 3, and the evaluation results are shown in Table 4 and Figure 5. In Table 3, AM, CM, and BM represent the active material (carbon-silicon / carbon composite), conductor (super P carbon black), and binder (styrene-butadiene rubber / carboxymethyl cellulose 5:5), respectively; EC, EMC, DMC, FEC, VC, and PS represent ethyl carbonate, methyl ethyl carbonate, dimethyl carbonate, fluoroethylene carbonate, ethylene carbonate, and propanesulfonate lactone, respectively. Table 3 Composition (AM:CM:BM) 8:1:1 Area capacity (mAh / cm2) 1 electrolytes 1.3M LiPF6 EC / EMC / DMC 3:5:2, FEC 10%, LiBF4 0.2%, 0.5% VC, 1% PS Cut-off voltage (V) Formation: 0.005-1.5, Cyclic test: 0.005-1.2 C-rate (C) Formation: 0.1-0.1, cutoff at 0.01C at 0.005V (CV) Table 4 sample polymer types polymer Average film thickness (nm) Discharge capacity (mAh / g) ICE (%) loop Retention rate (%) loop Example 1 pDVB 10 1629 84.9 21.2 50 Example 2 pDMAMS 10 1630 85.1 20.8 50 Example 3 pPFDA 10 1962 86.1 31.8 50 Example 4 pGMA 10 1596 81.2 19.5 50 Example 5 pDVB 1 1618 85.2 22.9 50 Example 6 pDVB 500 1204 74.6 7.7 44 Comparative Example 1 - - 1724 86 9.7 50

[0161] As confirmed by Table 4 and Figure 5 above, Examples 1 to 5 show reversible capacities of over 1500 mAh / g, and it can be confirmed that ICE and cyclic retention are excellent.

[0162] Furthermore, in Example 6, compared to Examples 1 to 5, the average thickness of the polymer film is relatively thick, thus confirming that the reversible capacity is low and the loop retention rate is also reduced.

[0163] Furthermore, in Comparative Example 1, since no polymer film was formed, it can be confirmed that the loop retention rate was significantly reduced.

[0164] The above describes one embodiment of the present invention. However, the concept of the present invention is not limited to the embodiment presented in this specification. Those skilled in the art to which this invention pertains can easily propose other embodiments by adding, changing, deleting, or supplementing constituent elements within the same conceptual scope, and these also fall within the scope of the present invention.

[0165] 10: Carbon / Silicone Polymer Composite 11: Porous carbon support 12: Silicon 13: Polymer film 100: Cavity 200: Installation Department 300: Inlet 400: Outlet 500: Heating section 1000: Reactor

[0166] Domestic storage information (please note in order of storage institution, date, and number) none

[0167] Overseas storage information (please note in the order of storage country, institution, date, and number) none

Claims

1. A carbon / silicon-polymer composite, wherein, include: A carbon-silicon composite comprising a porous carbon support and silicon, wherein the porous carbon support has a total pore volume based on the total pore volume, with a mesopore volume ratio of 10-80% and an average particle size of 1-20 μm, and the silicon is disposed on the surface and inside the pores of the porous carbon support; and a polymer film disposed on the surface of the porous carbon support, inside the pores, and on the surface of the silicon.

2. The carbon / silicon-polymer composite as claimed in claim 1, wherein, The porous carbon support has a BET specific surface area of ​​300–3000 m² / g and a tap density of 0.05–0.5 g / mL.

3. The carbon / silicon-polymer composite as claimed in claim 1, wherein, In the total weight of the carbon / silicon-polymer composite, silicon accounts for 5 to 80% by weight.

4. The carbon / silicon-polymer composite as claimed in claim 1, wherein, In the total weight of the carbon / silicon-polymer composite, the polymer film accounts for 1 to 30% by weight.

5. The carbon / silicon-polymer composite as claimed in claim 1, wherein, The thickness of the polymer film is 1–450 nm.

6. A method for preparing a carbon / silicon-polymer composite, wherein, include: Step (1) Silicon is formed on the surface and inside the pores of a porous carbon support with a pore size of 2-50 nm as the basis and a mesopore volume ratio of 10-80% and an average particle size of 1-20 μm to prepare a carbon-silicon composite; and Step (2) A polymer film is formed on the surface of the porous carbon support, inside the pores and on the surface of the silicon in the carbon-silicon composite by initiation chemical vapor deposition to prepare a carbon / silicon-polymer composite.

7. The method for preparing the carbon / silicon-polymer composite as described in claim 6, wherein, Step (2) includes: step (2-1), supplying a carbon-silicon composite into a reactor; step (2-2), supplying a monomer and an initiator into the reactor supplying the carbon-silicon composite; and step (2-3), polymerizing the monomer by activating the initiator to form a polymer film on the surface of the porous carbon support of the carbon-silicon composite, inside the pores, and on the surface of the silicon.

8. The method for preparing the carbon / silicon-polymer composite as described in claim 7, wherein, In step (2-2), the monomer is supplied at a flow rate of 0.1 sccm to 10 sccm, and the initiator is supplied at a flow rate of 0.1 sccm to 5 sccm.

9. The method for preparing the carbon / silicon-polymer composite as described in claim 7, wherein, The initiator is activated by a predetermined heat treatment, which is performed at a temperature of 135–350°C.

10. The method for preparing a carbon / silicon-polymer composite as claimed in claim 7, wherein step (2-3) is performed under a vacuum at a pressure of 50 to 1000 mTorr for 10 minutes to 6 hours.

11. A negative electrode material, wherein, include: Such as the carbon / silicon-polymer composite of any of the claims 1 to 5; And carbon-based anode materials.

12. An all-solid-state battery, wherein, Includes a solid electrolyte interface membrane, said solid electrolyte interface membrane comprising a carbon / silicon-polymer composite as claimed in any one of claims 1 to 5.

13. A lithium-ion battery, wherein, This includes negative electrode materials such as those in Request 11.

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