Carbon / silicon-carbon composite, manufacturing method therefor, and negative electrode active material and all-solid-state battery comprising same

Abstract

The present invention relates to a carbon / silicon-carbon composite and a method for manufacturing same. The carbon / silicon-carbon composite according to an embodiment of the present invention has excellent thickness uniformity of a carbon thin film, has excellent electrical conductivity when applied to a battery, can relieve stress caused by volume expansion of silicon, can exhibit an excellent capacity retention rate, and can exhibit excellent cycle life.

Description

Carbon / silicon-carbon composite, method for producing the same, negative electrode active material and all-solid-state battery containing the same

[0001] The present invention relates to a carbon / silicon-carbon composite, and more particularly, to a carbon / silicon-carbon composite, a method for producing the same, an anode active material comprising the same, and an all-solid-state battery.

[0002] With the recent development of the information and communication industry, demand for electronic devices has been rapidly increasing, and with the revitalization of the electric vehicle market, demand for batteries used in these electronic devices and electric vehicles has also increased significantly.

[0003] Secondary batteries, including lithium secondary batteries and all-solid-state batteries containing liquid electrolytes, are the most widely used for these applications due to their high energy density and minimal 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 the negative electrode active material.

[0004] Recently, attempts have been made to use silicon-based anode active materials to improve the capacity of secondary batteries. Silicon, with its theoretically very high energy density, is attracting attention as a next-generation battery anode material to replace graphite. However, it reacts with lithium during charging and discharging, increasing its volume by up to 300%. This causes the silicon anode material to fracture during charging and discharging, resulting in significantly reduced mechanical stability.

[0005] To solve these problems, Japanese Patent No. 4393610 discloses a negative electrode active material in which silicon is composited with carbon in a mechanical processing process and the surface of the silicon particles is covered with a carbon layer using a chemical vapor deposition (CVD) method. However, there is a limit to suppressing volume expansion and contraction during charge and discharge.

[0006] In addition, silicon-based negative electrode active materials have a problem in that the solid electrolyte interphase (SEI) layer that is excessively generated during the process of crushing and pulverizing silicon raw materials exhibits instability, which causes a decline in the stability and electrical performance of the battery.

[0007] An object of the present invention is to provide a carbon / silicon-carbon composite in which a carbon film is formed on a carbon / silicon composite coated with silicon, including the surface of a carbon support.

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

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

[0010] In order to solve the above-described problem, the present invention provides a carbon / silicon-carbon composite including a carbon support, silicon arranged including a surface of the carbon support, and a carbon thin film arranged including a surface of the carbon support and a surface of the silicon.

[0011] According to one embodiment of the present invention, the carbon support may include a non-porous carbon support including at least one of hard carbon and soft carbon.

[0012] Additionally, the carbon support may be a porous carbon support, the silicon may be disposed on the surface and inside the pores of the porous carbon support, and the carbon thin film may be disposed on the surface, inside the pores, and on the surface of the silicon of the porous carbon support.

[0013] Additionally, the porous carbon support may have a volume ratio of mesopores having a pore size of 2 to 50 nm of 10 to 80% based on the total pore volume.

[0014] In addition, the porous carbon support may have a BET specific surface area of ​​300 to 3,000 m2 / g, a tap density of 0.05 to 0.5 g / ㎖, and a particle size distribution D50 of 1 to 20 ㎛.

[0015] Additionally, the silicon may be 5 to 80 wt% of the total weight of the carbon / silicon-carbon composite.

[0016] Additionally, the carbon film may be 0.5 to 30 wt% of the total weight of the carbon / silicon-carbon composite.

[0017]

[0018] In addition, the present invention provides a method for producing a carbon / silicon-carbon composite, comprising the steps of (1) forming silicon including the surface of a carbon support to produce a carbon / silicon composite, (2) forming a polymer thin film including the surface of the carbon support and the surface of the silicon of the carbon / silicon composite through an initiator-based chemical vapor deposition (iCVD) to produce a carbon / silicon-polymer composite, and (3) carbonizing the polymer thin film of the carbon / silicon-polymer composite to produce a carbon / silicon-carbon composite.

[0019] According to one embodiment of the present invention, the step (2) may include: (2-1) a step of supplying a carbon / silicon composite into a reactor, (2-2) a step of supplying a monomer and an initiator to the reactor into which the carbon / silicon composite has been supplied, and (2-3) a step of activating the initiator to polymerize the monomer, thereby forming a polymer thin film including the surface of the carbon support of the carbon / silicon composite and the surface of the silicon.

[0020] Additionally, the polymer thin film may have a thickness of 1 nm to 10 μm.

[0021] Additionally, in the above 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.

[0022] Additionally, the initiator can be activated through a predetermined heat treatment, and the heat treatment can be performed at a temperature of 135 to 350°C.

[0023] Additionally, the above steps (2-3) can be performed in a vacuum state at a pressure of 50 to 1,000 mTorr for 10 minutes to 6 hours.

[0024] Additionally, the carbonization in step (3) can be performed by heat treatment at a temperature of 400 to 1,400°C.

[0025]

[0026] In addition, the present invention provides a negative electrode active material comprising the above-described carbon / silicon-carbon composite and a carbon-based negative electrode material.

[0027]

[0028] In addition, the present invention provides an all-solid-state battery including a SEI (Solid Electrolyte Interphase) film including the above-described carbon / silicon-carbon composite.

[0029]

[0030] The expression "arranged including the surface of the carbon support and the surface of the silicon" used in the present invention is an expression that includes both 1) being arranged so as to be in contact with the silicon surface arranged on the surface of the carbon support, but not in contact with the surface of the carbon support, and 2) being arranged so as to be in contact with the silicon surface arranged on the surface of the carbon support, but also in contact with at least a portion of the surface of the carbon support.

[0031] A carbon / silicon-carbon composite according to an embodiment of the present invention has excellent thickness uniformity of a carbon thin film, excellent electrical conductivity when applied to a battery, can relieve stress caused by volume expansion of silicon, can exhibit excellent capacity retention, and can exhibit excellent cycle life.

[0032] FIG. 1 schematically illustrates a process for forming a polymer thin film on a carbon / silicon composite using an initiator-based chemical vapor deposition (iCVD) method according to one embodiment of the present invention.

[0033] Figure 2 is a schematic diagram of a carbon / silicon-carbon composite according to one embodiment of the present invention.

[0034] FIG. 3 shows the XPS (X-ray Photoelectron Spectroscopy) analysis results (FIG. 3a) of the composites according to Preparation Example 1 and Examples 1-1 to 1-2 of the present invention, including the XPS analysis results for the carbon / silicon composite according to Preparation Example 1 (FIG. 3b), the carbon / silicon-polymer composite according to Example 1-1 (FIG. 3c), and the carbon / silicon-polymer composite according to Example 1-2 (FIG. 3d).

[0035] FIG. 4 is an XPS analysis result (FIG. 4a) of a composite according to Preparation Example 2 of the present invention, Examples 2-1 to 2-2, and is an XPS analysis result for graphite according to Preparation Example 2 (FIG. 4b), a graphite-polymer composite according to Example 2-1 (FIG. 4c), and a graphite-polymer composite according to Example 2-2 (FIG. 4d).

[0036] FIG. 5 shows the XPS analysis results (FIG. 5a) of the composites according to Preparation Example 3 and Examples 3-1 to 3-2 of the present invention, including the XPS analysis results for the graphite / silicon composite according to Preparation Example 3 (FIG. 5b), the graphite / silicon-polymer composite according to Example 3-1 (FIG. 5c), and the graphite / silicon-polymer composite according to Implementation Example 3-2 (FIG. 5d).

[0037] Figure 6 shows the FT-IR analysis results of the complexes according to Manufacturing Examples 1 to 3 of the present invention.

[0038] Figure 7 shows the results of Raman spectroscopy analysis of the complex according to Examples 1-3 and Manufacturing Example 1 of the present invention.

[0039] FIG. 8 is a TEM-EDS (energy dispersive spectrometer) image (FIG. 8a) and a TEM (transmission electron microscope) image (FIG. 8b) of a complex according to Examples 1-4 of the present invention.

[0040] Figure 9 is a graph showing the XPS analysis results of the composites according to Examples 1-4 and Manufacturing Example 4 of the present invention and the composites according to Preparation Example 1 and Manufacturing Example 4.

[0041] The present invention is not limited to the contents disclosed below, and may be modified in various forms as long as the gist of the invention is not changed.

[0042] As used herein, the term “comprising” means that other components may be included unless otherwise stated.

[0043] All numbers and expressions indicating the amounts of components, reaction conditions, etc. described in this specification are to be understood as being modified in all cases by the term “about” unless otherwise stated.

[0044] In this specification, the description that one component is formed above / below another component or is connected or coupled to each other includes both the formation, connection or coupling between these components directly or indirectly through another component.

[0045] The present invention will be described in more detail below.

[0046] carbon / silicon-carbon composites

[0047] As illustrated in FIG. 2, according to one embodiment of the present invention, a carbon / silicon-carbon composite (10) is provided, which includes a carbon support (11), silicon (12) disposed including a surface of the carbon support (11), and a carbon thin film (13) disposed including a surface of the carbon support (11) and a surface of the silicon (12).

[0048] Meanwhile, the carbon / silicon-carbon composite may have a BET surface area of ​​200 m2 / g or less, preferably 100 m2 / g or less, and more preferably 50 m2 / g or less. If the BET surface area of ​​the carbon / silicon-carbon composite exceeds 200 m2 / g, a large number of SEI layers may be formed due to the reaction with the electrolyte due to the high BET, resulting in poor electrochemical performance.

[0049] Hereinafter, each component of a carbon / silicon-carbon composite (10) according to one embodiment of the present invention will be described.

[0050] carbon support

[0051] A carbon / silicon-carbon composite (10) according to an embodiment of the present invention includes a carbon support (11).

[0052] The above carbon support may be any carbon support commonly used in the art without limitation, but preferably, it may be at least one of a non-porous carbon support and a porous carbon support, more preferably, it may be at least one of hard carbon, soft carbon, carbon black, carbon nanotubes, graphene, carbon fiber, graphite, and a porous carbon support, and even more preferably, it may be at least one of graphite, hard carbon, soft carbon, and a porous carbon support, and even more preferably, it may be at least one of hard carbon, soft carbon, and a porous carbon support, which may be more advantageous in achieving the purpose of the present invention.

[0053] Meanwhile, according to one embodiment of the present invention, the carbon support may be a porous carbon support. In this case, the silicon (12) may be disposed on the surface and within the pores of the porous carbon support (11), and the carbon thin film (13) may be disposed on the surface of the porous carbon support (11), within the pores, and on the surface of the silicon (12) (Fig. 2).

[0054] The porous carbon support (11) above may have a volume ratio of mesopores having a pore size of 2 to 50 nm based on the total pore volume of 10 to 80%, preferably 30 to 60%, and more preferably 40 to 50%. If the volume ratio of the mesopores of the porous carbon support is less than 10%, there may be too many micropores, so that silicon and polymers (for forming a carbon thin film) may be formed relatively in large quantities on the outside of the particles, and if the volume ratio of the mesopores of the porous carbon support exceeds 80%, the hardness of the particles is insufficient, so that there is a concern that the structure of the electrode may collapse when manufactured using the same.

[0055] In addition, the porous carbon support (11) may have a BET specific surface area of ​​300 to 3,000 m2 / g. Preferably, the porous carbon support (11) may have a BET specific surface area of ​​300 to 1,500 m2 / g, more preferably, a BET specific surface area of ​​500 to 1,500 m2 / g. When the BET specific surface area of ​​the porous carbon support is less than 300 m2 / g, there may be too many macropores and thus insufficient effective pores, and when the BET specific surface area of ​​the porous carbon support exceeds 3,000 m2 / g, there may be too many micropores and thus a large amount of silicon and polymer (for forming a carbon thin film) may be deposited on the outside of the particles.

[0056] In addition, the porous carbon support (11) may have a tap density of 0.05 to 0.5 g / ㎖. Preferably, the porous carbon support (11) may have a tap density of 0.05 to 0.45 g / ㎖, more preferably, a tap density of 0.1 to 0.45 g / ㎖. When the tap density of the porous carbon support is less than 0.05 g / ㎖, process control may be difficult during deposition of the silicon source and formation of the polymer thin film (for forming a carbon thin film), which may result in a decrease in yield, and when the tap density of the porous carbon support exceeds 0.5 g / ㎖, uniform coating may be difficult during deposition of the silicon source and formation of the polymer thin film (for forming a carbon thin film).

[0057] And, the porous carbon support (11) can have a particle size distribution D50 of 1 to 20 ㎛. Preferably, the porous carbon support (11) can have a particle size distribution D50 of 3 to 20 ㎛, more preferably, a particle size distribution D50 of 3 to 10 ㎛. When the particle size distribution D50 of the porous carbon support is less than 1 ㎛, the silicon source and the monomer and initiator for forming the polymer thin film (for forming the carbon thin film) cannot sufficiently penetrate into the pores and are deposited / adsorbed only to the outside of the particles, and when the particle size distribution D50 of the porous carbon support exceeds 20 ㎛, it is difficult for silicon and the polymer (for forming the carbon thin film) to sufficiently form in the pores.

[0058] When a carbon / silicon-carbon composite (10) according to an embodiment of the present invention includes a porous carbon support (11) having the above characteristics, when such a carbon / silicon-carbon composite (10) is used as a negative electrode active material, it has excellent electrical conductivity and can relieve stress due to volume expansion of silicon.

[0059] silicone

[0060] A carbon / silicon-carbon composite (10) according to an embodiment of the present invention includes silicon (12) arranged including the surface of the carbon support (11).

[0061] By arranging the carbon support (11) and silicon (12) in the carbon / silicon-carbon composite (10) according to the present invention as described above, and in particular, by arranging silicon on the surface and inside the pores of the carbon support, which is a porous carbon support, the negative electrode material manufactured from the carbon / silicon-carbon composite (10) according to the present invention can have a high electrical capacity while minimizing the influence due to volume expansion of silicon.

[0062] At this time, since the silicon (12) plays a role in charging lithium, when the carbon / silicon-carbon composite (10) according to the embodiment of the present invention is used as a negative electrode active material, the silicon can act as a main negative electrode active material.

[0063] The silicon (12) above may be crystalline or amorphous, and preferably may be amorphous or a similar phase. When the silicon (12) is crystalline, the smaller the crystallite size, the more dense the composite can be, so that the strength of the matrix is ​​strengthened and cracks can be prevented. Accordingly, the initial efficiency or cycle life characteristics of the secondary battery can be improved. Meanwhile, when the silicon (12) is amorphous or a similar phase, the expansion or contraction during charge and discharge of the secondary battery is small, and the battery performance such as the capacity characteristics can be improved.

[0064] The above silicon may be in the form of a thin film, and the average layer thickness of the silicon may be 10 nm to 5 μm. If the average layer thickness of the silicon is less than 10 nm, the electric capacity may be reduced, and if the average thickness exceeds 5 μm, the problem caused by volume expansion of the silicon may not be resolved, which may cause structural damage to the negative electrode material and deteriorate the cycle characteristics.

[0065] Meanwhile, the silicon (12) may be 5 to 80 wt% of the total weight of the carbon / silicon-carbon composite (10) according to the present invention, and preferably 10 to 50 wt%. If the silicon is less than 5 wt% of the total weight of the carbon / silicon-carbon composite, the electric capacity may decrease, and if the silicon is more than 80 wt%, the problem caused by the volume expansion of silicon during charge and discharge may not be solved, which may cause structural damage to the negative electrode material and deteriorate the cycle characteristics.

[0066] The above silicon (12) may further include a silicon oxide compound. The silicon oxide compound has the general formula SiO x It can be expressed as (0.5≤x≤2). Here, when the value of x is less than 0.5, expansion and contraction may increase and the life characteristics may deteriorate during charging and discharging of the secondary battery, and when x exceeds 2, the initial efficiency of the secondary battery may decrease as the amount of inactive oxide increases.

[0067] The content of the silicon oxide compound in the silicon may be 50 wt% or less based on the total weight of the silicon. If the content of the silicon oxide compound in the silicon exceeds 50 wt%, the initial efficiency of the secondary battery may be reduced.

[0068] polymer thin films

[0069] A carbon / silicon-carbon composite (10) according to an embodiment of the present invention includes a carbon thin film (13) arranged including the surface of the carbon support (11) and the surface of the silicon (12), and the carbon thin film is formed by carbonizing a predetermined polymer thin film.

[0070] The above polymer thin film is formed by the initiator-based chemical vapor deposition (iCVD) method described below.

[0071] The polymer thin film is formed by iCVD, and the type of material is not particularly limited as long as it has little effect on the electrical conductivity and lithium ion conductivity of the negative electrode active material. Specifically, the polymer thin film may be a polymerization or copolymerization of at least one vinyl or acrylate monomer containing at least one of a siloxane group, an amine group, a fluorine group, a glycidyl group, and an aromatic hydrocarbon group.

[0072] In a specific example of the present invention, the polymer thin film is selected from the group consisting of 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 methacrylate (PFDMA), 1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane (V4D4), 1,3,5-trimethyl-1,3,5-trivinylcyclotrisiloxane (V3D3), hexavinyldisiloxane (HVDS), glycidyl methacrylate, divinylbenzene, diethylene glycol divinyl ether, diethylene glycol diacrylate (DEGDA), ethylene glycol dimethacrylate, dimethylaminoethyl methacrylate, methacrylic acid and 1,3-diethenyl-1,1,3,3-tetramethyl-disiloxane, 1H,1H,2H,2H-Perfluorodecyl acrylate, 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-Tridecafluorooctyl acrylate, 2-Methyl-3,3,4,4,5,5,6,6,7,7,8,8,8-Tridecafluorooctyl acrylate, 3,3,4,4,5,5,6,6,7,7,7-Undecafluoroheptyl acrylate, 2-Methyl-3,3,4,4,5,5,6,6,7,7,7-undecafluoroheptyl acrylate, 3,3,4,4,5,5,6,6,6-nonafluorohexyl acrylate, 2-methyl-3,3,4,4,5,5,6,6,6-nonafluorohexyl acrylate, 3,3,4,4,5,5,6,6,6-nonafluorohexyl acrylate, 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,11-nonadecafluoroundecyl acrylate, 2-methyl-3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,11-nonadecafluoroundecyl acrylate, 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,12-Heneicosafluorododecyl acrylate, 2-methyl-3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,12-Heneicosafluorododecyl acrylate, 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,13,13,13-Tricosafluorotridecyl 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-Tricosafluorotridecyl 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-pentacosafluorotetradecyl acrylate, and 2-Methyl-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-pentacosafluorotetradecyl acrylate, dimethylaminoethyl methacrylate, dimethylaminoethyl acrylate, diethylaminoethyl methacrylate, and may be polymerized from one or more monomers selected from the group consisting of diethylaminoethyl acrylate.

[0073] In a preferred embodiment of the present invention, the polymer thin film may be polymerized from one or more monomers selected from the group consisting of 1H,1H,2H,2H-perfluorodecyl acrylate, dimethylaminomethyl styrene, divinylbenzene, glycidyl methacrylate, 1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane, 1,3,5-trimethyl-1,3,5-trivinylcyclotrisiloxane, and hexavinyldisiloxane, but is not particularly limited thereto.

[0074] Meanwhile, the polymer film can be converted into a carbon film through carbonization, and at least some of the polymer film residue remaining after being removed during carbonization may exist on the carbon / silicon-carbon composite. Accordingly, the carbon / silicon-carbon composite according to an embodiment of the present invention may include at least some of the polymer film residue.

[0075] carbon thin film

[0076] A carbon / silicon-carbon composite (10) according to an embodiment of the present invention includes a carbon thin film (13) arranged including the surface of the carbon support (11) and the surface of the silicon (12).

[0077] The carbon / silicon-carbon composite (10) according to the embodiment of the present invention can secure appropriate electrical conductivity by including a carbon thin film (13) and can appropriately control its specific surface area, so that when used as a negative electrode active material of a secondary battery, the life characteristics and capacity of the secondary battery can be further improved.

[0078] The electrical conductivity of a negative active material is an important factor that facilitates electron transfer during an electrochemical reaction. The carbon / silicon-carbon composite (10) according to an embodiment of the present invention, which includes the carbon thin film (13), improves the charge / discharge capacity, initial charge efficiency, and capacity retention rate of a secondary battery, provides excellent electrical conductivity, suppresses side reactions of the electrolyte, and further enhances the performance of the secondary battery.

[0079] Meanwhile, the carbon film may be 0.5 to 30 wt% of the total weight of the carbon / silicon-carbon composite (10) according to the present invention, and preferably 0.5 to 20 wt%. When the carbon film satisfies the above content range of the total weight of the carbon / silicon-carbon composite, the effect of improving conductivity can be obtained while suppressing a decrease in the capacity of the secondary battery.

[0080]

[0081] Method for producing carbon / silicon-carbon composites

[0082] According to one embodiment of the present invention, a carbon / silicon-carbon composite is manufactured by a manufacturing method including the steps of (1) forming silicon including the surface of a carbon support to manufacture a carbon / silicon composite, (2) forming a polymer thin film including the surface of the carbon support and the surface of the silicon of the carbon / silicon composite through an initiator-based chemical vapor deposition (iCVD) to manufacture a carbon / silicon-polymer composite, and (3) carbonizing the polymer thin film of the carbon / silicon-polymer composite to manufacture a carbon / silicon-carbon composite.

[0083] Hereinafter, each step of a method for manufacturing a carbon-silicon / carbon composite according to one embodiment of the present invention is described.

[0084] (1) Step

[0085] In step (1) above, a carbon / silicon composite is manufactured by forming silicon including the surface of a carbon support.

[0086] Meanwhile, if the carbon support is a porous carbon support, the step (1) may be a step of manufacturing a carbon / silicon composite by forming it on the surface and inside the pores of the porous carbon support.

[0087] In a specific embodiment of the present invention, the step of forming silicon including the surface of a carbon support may be performed using a device (e.g., a rotary kiln) and a method (e.g., chemical vapor deposition (CVD)) known in the art to which the present invention pertains. Specifically, silicon including the surface of the carbon support may be formed by supplying a silicon source to the carbon support and performing CVD.

[0088] In a specific embodiment 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.

[0089] The CVD of the above silicon source can be performed at a temperature of 300 to 700°C. For example, the CVD of the silicon source can be performed at a temperature of 400 to 600°C, 400 to 500°C, or 400 to 450°C, but is not particularly limited to this range.

[0090] (2) Step

[0091] In the above step (2), a polymer thin film is formed through an initiator-based chemical vapor deposition (iCVD) method, including the surface of the carbon support and the surface of the silicon of the carbon / silicon composite, to manufacture a carbon / silicon-polymer composite.

[0092] Meanwhile, when the carbon support is a porous carbon support, the step (2) may be a step of manufacturing a carbon / silicon-polymer composite by forming a polymer thin film on the surface of the carbon / silicon composite, inside the pores, and on the surface of the silicon through an initiator-based chemical vapor deposition (iCVD).

[0093] Here, initiator-assisted chemical vapor deposition (iCVD) refers to a process that polymerizes monomers by decomposing a vapor-phase initiator into radicals. Since initiator-assisted chemical vapor deposition (iCVD) involves supplying energy from a heat source such as a heated filament or UV light to deposit a polymer thin film, it may not seem much different from the conventional CVD process for inorganic thin film deposition. However, in the iCVD process, the initiator is activated at a low temperature in the range of 135 to 350°C, preferably in the range of 140 to 340°C. In addition, the surface temperature of the carbon / silicon composite on which the polymer thin film is deposited is maintained low, in the range of 10 to 50°C, preferably in the range of 13 to 45°C. Due to this low surface temperature, iCVD can be effectively used to deposit polymer thin films on various substrates that are vulnerable to mechanical or chemical shock. In addition, the above iCVD process does not require high vacuum equipment because it is performed in a vacuum state ranging from 50 to 1,000 mTorr, preferably in a vacuum state ranging from 60 to 900 mTorr.

[0094] Meanwhile, according to one embodiment of the present invention, the step (2) may include: (2-1) a step of supplying a carbon / silicon composite into a reactor, (2-2) a step of supplying a monomer and an initiator to the reactor to which the carbon / silicon composite has been supplied, and (3) a step of activating the initiator to polymerize the monomer, thereby forming a polymer thin film including the surface of the porous carbon support of the carbon / silicon composite and the surface of the silicon.

[0095] FIG. 1 schematically illustrates a process for forming a polymer thin film using an initiator-assisted chemical vapor deposition (iCVD) method, including a porous carbon support surface and the silicon surface, according to an embodiment of the present invention. Referring to FIG. 1, a method for manufacturing the carbon / silicon-polymer composite will be described.

[0096] Step (2-1)

[0097] In the above step (2-1), a carbon / silicon composite is supplied into the reactor.

[0098] The structure of the reactor used in the method for manufacturing a carbon / silicon-polymer composite according to one embodiment of the present invention is not particularly limited as long as it can form a polymer thin film on the carbon / silicon composite using the initiator-based chemical vapor deposition (iCVD) method described below.

[0099] In a specific embodiment of the present invention, the reactor (10) may include a chamber (100), a mounting portion (200), an inlet (300), an outlet (400), and a heating portion (500).

[0100] The above carbon / silicon composite can be placed on a mounting portion (200) provided at the bottom of the chamber (100) of the reactor (10). 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 may be a flat plate on which the carbon / silicon composites can be placed while spreading out so as not to overlap each other as much as possible. More specifically, a silicon substrate (wafer) may be used as the mounting portion for accommodating the carbon / silicon composite, but this is not particularly limited.

[0101] The above-described mounting portion may 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, to change or rotate the position of the carbon / silicon composite placed on the silicon substrate, thereby allowing a polymer film to be evenly formed on the carbon / silicon composite in step (2-3) described below, but is not particularly limited thereto.

[0102] Step (2-2)

[0103] In the above step (2-2), monomers and initiators are supplied to the reactor.

[0104] At this time, the monomer (M) and the initiator (I) can be vaporized and supplied to the chamber (100) through the inlet (300) of the reactor (10).

[0105] The above monomer (M) is a volatile substance that can be activated by an initiator (I) to form a polymer. Details of the above monomer are as described in the carbon / silicon-polymer composite section above.

[0106] The above initiator (I) is a substance that decomposes by heat or light to form a free radical, and its type is not particularly limited as long as it is a substance that can activate the monomer to form a polymer. Preferably, the initiator may be a peroxide. Specifically, the initiator may include at least one selected from the group consisting of di-t-butyl peroxide, t-butyl peroxybenzoate, benzoyl peroxide, methyl ethyl ketone peroxide, lauryl peroxide, and benzophenone, but is not particularly limited thereto. Most preferably, the initiator may be di-t-butyl peroxide.

[0107] At this time, the monomer flow rate in the reactor may be 0.1 sccm to 10 sccm. Specifically, the monomer flow rate may be 0.1 sccm or more, or 0.1 sccm or more and 10 sccm or less, 5 sccm or less, or 4 sccm or less.

[0108] Additionally, the initiator flow rate within the reactor may be 0.1 sccm to 5 sccm. Specifically, the initiator flow rate may be 0.1 sccm or more and 5 sccm or less, 3 sccm or less, or 2 sccm or less.

[0109] As the monomer flow rate and initiator flow rate satisfy the above ranges, it can be more advantageous to achieve the purpose of the present invention.

[0110] Step (2-3)

[0111] In the above step (2-3), the initiator is activated to polymerize the monomer, thereby forming a polymer thin film including the surface of the porous carbon support of the carbon / silicon composite and the surface of the silicon.

[0112] First, the initiator (I) supplied into the chamber (100) of the reactor (10) in a vaporized state is activated by contact with the heating unit (500) to generate free radicals (I *) is formed. The heating unit may be, for example, a plurality of filaments heated by electricity, but is not particularly limited thereto. The temperature of the heating unit is not limited in the range as long as it can decompose and activate the initiator, but is preferably in the range of 135 to 350°C, more preferably in the range of 140 to 340°C, which may be advantageous in terms of preventing changes in the properties of the reactants.

[0113] Free radicals (I) generated from the above initiator * ) and monomer (M) move to the bottom of the chamber and are adsorbed on the porous carbon support surface of the carbon / silicon composite accommodated in the mounting portion (200) and the surface of the silicon. The adsorbed monomer, including the porous carbon support surface of the carbon / silicon composite and the surface of the silicon, is free radical (I * ) activated by (M * ) and polymerization proceeds to form a polymer thin film including the surface of the porous carbon support of the carbon / silicon composite and the surface of the silicon.

[0114] The initiator and monomer remaining in the gas phase used in the reaction of the above step (2-3) can be discharged out of the reactor through the outlet (400).

[0115] In the above step (2-3), in order to increase the adsorption rate of the monomer and free radicals, it is preferable to keep the temperature of the surface of the carbon / silicon composite low. Specifically, the temperature of the surface of the carbon / silicon composite is preferably in the range of 10 to 50°C, preferably in the range of 13 to 45°C, but is not particularly limited to this range. In order to maintain the temperature of the surface of the carbon / silicon composite within the above range, the reactor (10) may additionally include a cooling unit (not shown) disposed below the mounting unit (200). The cooling unit (not shown) is not particularly limited in its cooling method, structure, etc., as long as it can control the temperature of the surface of the carbon / silicon composite within the above range.

[0116] The above steps (2-3) can be performed under a vacuum condition of 50 to 1,000 mTorr, preferably 60 to 900 mTorr. This vacuum range can be provided by a simple rotary pump rather than a high vacuum pump.

[0117] In addition, the above step (2-3) can be carried out for 10 minutes to 6 hours, preferably 30 minutes to 2 hours, but is not limited thereto. However, as the reaction time satisfies the above time range, a polymer thin film of the desired thickness can be uniformly formed.

[0118] The properties of the polymer thin film formed in the above steps (2-3) can be easily controlled by controlling the process variables of iCVD. That is, by controlling the pressure and temperature within the chamber, reaction time, flow rates of initiators and monomers, the temperature of the heating section and the surface and pores of the carbon / silicon composite (when using a porous carbon support), etc., the molecular weight, thickness, composition, deposition rate, etc. of the polymer thin film can be easily controlled.

[0119] Meanwhile, the polymer thin film of the carbon / silicon-polymer composite manufactured by performing the above step (2) may have a thickness of 1 nm to 10 μm, preferably 1 nm to 8 μm. As the polymer thin film satisfies the above thickness range, the effect of improving conductivity after forming the carbon thin film can be obtained, while suppressing a decrease in the capacity of the secondary battery.

[0120]

[0121] (3) Step

[0122] In the above step (3), the polymer thin film of the carbon / silicon-polymer composite is carbonized to produce a carbon / silicon-carbon composite.

[0123] At this time, the carbonization may be performed at a temperature of 400 to 1,400°C, preferably at a temperature of 500 to 1,400°C, more preferably at a temperature of 600 to 1,400°C, and even more preferably at a temperature of 650 to 1,400°C. If the temperature is below the range, a carbon film may not be formed at the desired level, and if the temperature exceeds the range, the carbon / silicon-carbon composite may be damaged.

[0124] Meanwhile, at least a portion of the polymer thin film residue remaining after being removed during the carbonization process may be present on the carbon / silicon-carbon composite. Accordingly, the carbon / silicon-carbon composite according to an embodiment of the present invention may include at least a portion of the polymer thin film residue.

[0125]

[0126] Preliminary stage

[0127] As described above, the carbon support may be any carbon support commonly used in the art without limitation, but preferably, at least one of a non-porous carbon support and a porous carbon support may be used, more preferably, at least one of graphite, hard carbon, soft carbon, and porous carbon support may be used, and even more preferably, using at least one of hard carbon, soft carbon, and porous carbon support may be more advantageous in achieving the purpose of the present invention.

[0128] When the carbon support is a porous carbon support, the method for producing the carbon / silicon-carbon composite may further include, before step (1), (a) a step of synthesizing pitch by thermal decomposition and polycondensation of a petroleum-based raw material, (b) a step of solidifying and pelletizing the pitch to obtain a pellet-like pitch or a step of solidifying, pelletizing, and pulverizing the pitch to obtain a powder-like pitch, (c) a step of stabilizing the pellet-like pitch or the powder-like pitch, (d) a step of carbonizing the stabilized pitch to obtain a carbonized body, and (e) a step of activating the carbonized body to obtain a porous carbon support.

[0129] In the above step (a), pitch can be synthesized by thermal decomposition and polycondensation of petroleum-based raw materials.

[0130] In a specific embodiment of the present invention, the petroleum-based raw material may include at least one selected from the group consisting of pyrolysis fuel oil (PFO), naphtha cracking residue (NCB), ethylene cracker bottom oil (EBO), vacuum residue (VR), de-asphalted oil (DAO), atmospheric residue (AR), fluid catalytic cracking (FCC-DO) oil, residue fluid catalytic cracking decant oil (RFCC-DO), and heavy aromatic oil. In a preferred specific embodiment of the present invention, the petroleum-based raw material may include pyrolysis fuel oil.

[0131] In a specific embodiment of the present invention, the petroleum-based raw material may contain an aromatic compound in an amount of 10 to 90 wt%. Preferably, the petroleum-based raw material may contain an aromatic compound in an amount of 20 to 80 wt%, more preferably 30 to 70 wt%. When the content of the aromatic compound in the petroleum-based raw material satisfies the above range, even if the solid pitch pellets described below are stabilized, carbonized, and activated without separately pulverizing, a porous carbon support having controlled pore characteristics can be obtained.

[0132] In a specific embodiment of the present 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, tetralin, and fluorene. In this case, even if the solid pitch pellets described below are stabilized, carbonized, and activated without separately pulverizing, a porous carbon support having controlled pore characteristics can be obtained.

[0133] In a specific embodiment of the present invention, the thermal decomposition and polycondensation of the petroleum-based raw material can be carried out at a temperature of 350 to 500°C. In a preferred specific embodiment of the present invention, the thermal decomposition and polycondensation of the petroleum-based raw material can be carried out at a temperature of 400 to 500°C. In a more preferred specific embodiment of the present invention, the thermal decomposition and polycondensation of the petroleum-based raw material can be carried out at a temperature of 430 to 470°C. When the temperature of the thermal decomposition and polycondensation of the petroleum-based raw material is 350 to 500°C, a pitch containing a large amount of relatively low molecular weight components can be produced, and in the activation process of step (e) described below, components having relatively small molecular weights are vaporized first, thereby sufficiently forming mesopores in the carbon support. If the thermal decomposition and polycondensation temperature of petroleum-based raw materials is less than 350°C, it is difficult to manufacture pitch that is solid at room temperature, and if this temperature exceeds 500°C, the pitch contains a lot of relatively high molecular weight components, making it difficult to manufacture a carbon support having mesopores.

[0134] In a specific embodiment of the present invention, the thermal decomposition and polycondensation of the petroleum raw material may be performed under an atmosphere of an oxidizing gas, an inert gas, or a mixture thereof. In a preferred specific embodiment of the present invention, the oxidizing gas may be oxygen, ozone, or a combination thereof, the inert gas may be nitrogen, helium, neon, argon, or a combination thereof, and the mixture thereof may be air, but is not particularly limited thereto.

[0135] When an oxidizing gas is used during the thermal decomposition and polycondensation of petroleum-based raw materials, a pitch with a high softening point can be produced, but it is difficult to perform the thermal decomposition and polycondensation at high temperatures. When an inert gas is used during the thermal decomposition and polycondensation of petroleum-based raw materials, thermal decomposition and polycondensation can be performed at high temperatures, but it is difficult to produce a pitch with a relatively high softening point. When a mixed gas of an oxidizing gas and an inert gas is used during the thermal decomposition and polycondensation of petroleum-based raw materials, thermal decomposition and polycondensation can be performed at relatively high temperatures, thereby producing a pitch with a relatively high softening point.

[0136] In a specific embodiment of the present invention, the gas may be supplied at a flow rate of 10 to 800 ml / min during the thermal decomposition and polycondensation of a petroleum-based raw material. In a preferred specific embodiment of the present invention, the gas may be supplied at a flow rate of 100 to 500 ml / min during the thermal decomposition and polycondensation of a petroleum-based raw material. When the flow rate of the gas is less than 10 ml / min, the yield of the pitch increases, but the low molecular weight component increases too much, which is disadvantageous for subsequent processes (e.g., stabilization). When the flow rate of the gas exceeds 800 ml / min, the yield of the pitch may decrease.

[0137] In a specific embodiment of the present invention, the thermal decomposition and polycondensation of the petroleum-based raw material can be carried out for 1 to 10 hours. In a preferred embodiment of the present invention, the thermal decomposition and polycondensation of the petroleum-based raw material can be carried out for 2 to 8 hours. In a more preferred embodiment of the present invention, the thermal decomposition and polycondensation of the petroleum-based raw material can be carried out for 2 to 7 hours. If the thermal decomposition and polycondensation time of the petroleum-based raw material is less than 1 hour, it is difficult to produce a pitch having a high softening point, and if the thermal decomposition and polycondensation time of the petroleum-based raw material exceeds 10 hours, an excessive amount of quinoline-insoluble components may be produced.

[0138] In a specific embodiment of the present invention, the thermal decomposition and polycondensation of the petroleum-based raw material may be performed under stirring. The stirring conditions for the petroleum-based raw material are not particularly limited, but, for example, a stirrer rotating at 10 to 500 rpm may be used.

[0139] In a specific embodiment of the present invention, the pitch synthesized in step (a) may have a softening point of 200 to 350°C. In a preferred embodiment of the present invention, the pitch may have a softening point of 200 to 330°C. In a more preferred embodiment of the present invention, the pitch may have a softening point of 200 to 300°C. Since the pitch manufactured according to the present invention has a high softening point, when used as a precursor for manufacturing a carbon support, the stabilization process is easy, and a high yield can be obtained after carbonization and activation.

[0140] In a specific embodiment of the present invention, the yield of the pitch synthesized in step (a) may be 10 to 50 wt%. In a preferred embodiment of the present invention, the yield of the pitch may be 10 to 40 wt%. In a more preferred embodiment of the present invention, the yield of the pitch may be 20 to 30 wt%.

[0141] In a specific embodiment of the present invention, a step of pretreating the petroleum-based raw material may be performed prior to step (a). By removing low-boiling-point components contained in the petroleum-based raw material through the pretreating step, a pitch having a higher softening point can be produced.

[0142] In a specific embodiment of the present invention, the pretreatment step may be performed 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 performed at 250 to 450°C, preferably 250 to 400°C, and more preferably 300 to 400°C.

[0143] In a specific embodiment of the present invention, the pretreatment step may be performed for a time equal to or shorter than the thermal decomposition and polycondensation time of the petroleum-based raw material in step (a), but is not particularly limited to this condition. Specifically, the pretreatment step may be performed for 1 to 8 hours, preferably 1 to 6 hours, and more preferably 1 to 5 hours.

[0144] Additionally, in the step (b), the pitch may be solidified and pelletized to obtain a pellet-like pitch, or the pitch may be solidified, pelletized, and pulverized to obtain a powder-like pitch.

[0145] First, in the case of the pellet-shaped pitch, the liquid pitch obtained in step (a) is solidified, for example, by extrusion and cooling, and then pelletized into a desired size to obtain solid pitch pellets (pellet-shaped pitch). The process of extruding, cooling, and pelletizing the liquid pitch to obtain solid pitch pellets can be performed using commercially available equipment. For example, this process can be performed using IPCO's Double Belt Cooler & Flaker, but is not particularly limited to this equipment.

[0146] The pitch pellets obtained in step (b) have an average particle size (particle size distribution D50) of 1 to 30 mm, preferably 5 to 25 mm. When the average particle size (particle size distribution D50) of the pitch pellets is within this range, a porous carbon support can be manufactured through stabilization, carbonization, and activation described below without separately pulverizing the pitch pellets.

[0147] In addition, in the case of the above-mentioned powdered pitch, the pitch pellets (pellet-shaped pitch) can be further crushed or pulverized and classified. The pitch pellets can be further finely divided through crushing or pulverization, and the particle size distribution of the pitch pellets can be made uniform through classification. Here, the classification can be dry classification, wet classification, or classification using a sieve. By crushing or pulverizing and classification, a powdered pitch having an average particle size (particle size distribution D50) of 50 to 500 μm can be obtained.

[0148] And, in step (c), a step of stabilizing the pellet-shaped pitch or powder-shaped pitch can be performed.

[0149] First, the pitch obtained in step (b) is subjected to primary oxidation to stabilize the carbon structure of the pitch.

[0150] In a specific embodiment of the present invention, the stabilization of the pitch may be performed in an oxidizing gas atmosphere. In a preferred embodiment of the present invention, the stabilization of the pitch may be performed in an air atmosphere, but is not particularly limited thereto.

[0151] In a specific embodiment of the present invention, the stabilization of the pitch may be performed at a temperature of 100 to 500°C, preferably 150 to 300°C. When the stabilization of the pitch is performed at this temperature, the carbon structure within the pellet-shaped pitch or powder-shaped pitch changes from thermoplastic to thermosetting, so that the structure can be stably maintained during the subsequent carbonization process. At this time, the heating rate may be 2 to 10°C / min. If the heating rate is too slow, productivity may be poor, and if the heating rate is excessively fast, uniform stabilization treatment may be difficult.

[0152] In a specific embodiment of the present invention, the stabilization may be performed at a pressure of 0.1 to 10 bar, preferably 0.5 to 5 bar. When the stabilization is performed at this pressure, the structure of the pellet-shaped pitch or the carbon inside the powder-shaped pitch can be sufficiently stabilized.

[0153] In a specific embodiment of the present invention, the stabilization can be performed under conditions of a flow rate of an oxidizing gas, preferably air, of 0.1 to 500 ml / min, preferably 1 to 300 ml / min. When the stabilization is performed under these oxidizing gas flow rates, the structure of the carbon inside the pellet-shaped pitch or the powder-shaped pitch can be sufficiently stabilized.

[0154] In a specific embodiment of the present invention, the stabilization may be performed for 1 to 10 hours, preferably 2 to 8 hours. If the stabilization is performed for this period of time, the structure of the carbon within the pellet-shaped pitch or the powder-shaped pitch can be sufficiently stabilized.

[0155] And, in step (d), the stabilized pitch can be carbonized to obtain a carbonized body. Through carbonization of the stabilized pitch, other functional groups contained in the pitch are removed, and a carbonized body composed of substantially pure carbon can be obtained.

[0156] In a specific embodiment of the present invention, the carbonization may be performed under an inert gas atmosphere. In a preferred embodiment of the present invention, the carbonization may be performed under a nitrogen or argon atmosphere, but is not particularly limited thereto.

[0157] In a specific embodiment of the present invention, the carbonization may be performed at a temperature of more than 700°C and less than or equal to 1,000°C, preferably 800 to 900°C. If the temperature during the carbonization is lower than this range, carbonization may not be sufficiently performed, and if the temperature during the carbonization is higher than this range, the carbonization yield may decrease.

[0158] In a specific embodiment of the present invention, the carbonization may be performed under conditions of a flow rate of an inert gas, preferably nitrogen, of 0.1 to 30 ml / min, preferably 0.1 to 10 ml / min. When the carbonization is performed under these inert gas flow rates, the stabilized pitch can be sufficiently carbonized.

[0159] In a specific embodiment of the present invention, the carbonization may be performed for 0.5 to 5 hours, preferably 1 to 3 hours. If the carbonization is performed for this period of time, the stabilized pitch can be sufficiently carbonized.

[0160] And, in step (e), the carbonized body (carbonized pitch) is activated to obtain a porous carbon support. By activating the carbonized body, pores are formed in the pitch pellets, thereby obtaining a porous carbon support.

[0161] In a specific embodiment of the present invention, the activation of the carbonized body may be performed in an oxidizing gas atmosphere. In a preferred embodiment of the present invention, the activation of the carbonized body may be performed in a steam atmosphere, but is not particularly limited thereto.

[0162] In a specific example of the present invention, the activation of the carbonized body can be performed at a temperature of more than 700°C and less than or equal to 1,000°C, preferably 800 to 900°C. When the activation of the carbonized body is performed at this temperature, a porous carbon support in which micropores and mesopores are sufficiently formed can be obtained.

[0163] In a specific embodiment of the present invention, the activation of the carbonized body can be performed at a pressure of 0.1 to 10 bar, preferably 0.1 to 5 bar. When the activation of the carbonized body is performed at this pressure, a porous carbon support in which micropores and mesopores are sufficiently formed can be obtained.

[0164] In a specific embodiment of the present invention, the activation of the carbonized body can be performed under conditions of a flow rate of an oxidizing gas, preferably water vapor, of 0.1 to 100 ml / min, preferably 0.1 to 50 ml / min. When the activation of the carbonized body is performed under these oxidizing gas flow rates, a porous carbon support in which micropores and mesopores are sufficiently formed can be obtained.

[0165] In a specific embodiment of the present invention, the activation of the carbonized body may be performed for 0.5 to 5 hours, preferably 1 to 3 hours. When the activation of the carbonized body is performed for this period of time, a porous carbon support in which micropores and mesopores are sufficiently formed can be obtained.

[0166] In a specific embodiment of the present invention, the stabilization, carbonization, and activation of steps (c) to (e) above can each be performed in a microwave-assisted heating furnace. In a preferred embodiment of the present invention, the stabilization, carbonization, and activation of steps (c) to (e) above can all be performed in a microwave-assisted heating furnace. A microwave-assisted heating furnace is preferred because it can increase the temperature of the pitch itself without increasing the external temperature of the pitch, but is not particularly limited thereto.

[0167] In a specific embodiment of the present invention, the stabilization, carbonization, and activation of steps (c) to (e) above can be performed continuously in a single device. In a preferred embodiment of the present invention, the stabilization, carbonization, and activation of steps (c) to (e) above can be performed continuously in a single rotary kiln, but the device is not particularly limited thereto. By performing the stabilization, carbonization, and activation of steps (c) to (e) above continuously in a single device, optimization of the process can be achieved.

[0168] In a specific embodiment of the present invention, the porous carbon support obtained in step (e) can be further pulverized or ground and classified. The porous carbon support can be further finely divided through pulverization or ground, and the particle size distribution of the porous carbon support can be made uniform through classification. Here, the classification can be dry classification, wet classification, classification using a sieve, etc. By the pulverization or ground and classification treatment, a porous carbon support powder having an average particle diameter (particle size distribution D50) of 1 to 20 ㎛, a BET specific surface area of ​​300 to 3,000 m2 / g, and a tap density of 0.05 to 0.5 g / ㎖ can be obtained. In addition, the porous carbon support powder can have a volume ratio of mesopores having a pore size of 2 to 50 nm based on the total pore volume of 10 to 80%.

[0169] Meanwhile, in the case where the porous carbon support is obtained by stabilizing, carbonizing, and activating the pitch without further pulverizing in the above step (b), the carbon support may be pulverized (or further classified) to have an average particle size of 1 to 20 ㎛ (particle size distribution D50), but is not limited thereto.

[0170]

[0171] In addition, when the carbon support is hard carbon, the hard carbon can be manufactured by a method including the steps of (a') synthesizing pitch by thermal decomposition and condensation polymerization of petroleum-based raw materials, (b') solidifying and pelletizing the pitch to obtain pellet-like pitch, or solidifying, pelletizing, and pulverizing the pitch to obtain powder-like pitch, (c') stabilizing the pellet-like pitch or powder-like pitch, and (d') carbonizing the stabilized pitch to obtain hard carbon.

[0172] At this time, since the description of the above steps (a') to (d') may be the same as the description of the above steps (a) to (d), a detailed description will be omitted.

[0173] Meanwhile, the pitch for manufacturing the hard carbon may be at least one of an isotropic pitch and an anisotropic pitch, and it is more advantageous to achieve the purpose of the present invention to be an isotropic pitch.

[0174]

[0175] In addition, when the carbon support is soft carbon, the soft carbon can be manufactured by a method including the steps of (a) synthesizing pitch by thermal decomposition and condensation polymerization of a petroleum-based raw material, (b) solidifying and pelletizing the pitch to obtain a pellet-like pitch, or solidifying, pelletizing, and pulverizing the pitch to obtain a powder-like pitch, (c) stabilizing the pellet-like pitch or the powder-like pitch, and (d) carbonizing the stabilized pitch to obtain soft carbon.

[0176] At this time, since the description of the above steps (a”) and (b”) may be the same as the description of the above steps (a) and (b), a detailed description thereof will be omitted.

[0177] The above step (c”) and the step (d”) described below may be performed as a series of steps in a rotary kiln, as in the above-described steps (c) and (d), or may be performed as a series of steps by placing the product in a crucible and placing it in an oven. Preferably, it may be advantageous for achieving the purpose of the present invention to perform the series of steps by placing the product in a crucible and placing it in an oven.

[0178] Meanwhile, since the description of the contents other than the above step (c”) may be the same as the description of the above step (c), a detailed description will be omitted.

[0179] In addition, the above step (d”) is a step of carbonizing the stabilized pitch to obtain soft carbon, and through carbonization of the stabilized pitch, other functional groups included in the pitch are removed, and soft carbon composed of substantially pure carbon can be obtained.

[0180] In a specific embodiment of the present invention, the carbonization in step (d”) may be performed under an inert gas atmosphere. In a preferred embodiment of the present invention, the carbonization in step (d”) may be performed under a nitrogen or argon atmosphere, but is not particularly limited thereto.

[0181] In a specific embodiment of the present invention, the carbonization in step (d”) may be performed at a temperature of 1,000°C to 2,700°C, preferably 1,200°C to 2,200°C. If the temperature during the carbonization in step (d”) is lower than this range, the crystal structure of carbon may not develop sufficiently, and if the temperature during the carbonization is higher than this range, the carbonization yield may decrease.

[0182] In a specific embodiment of the present invention, the carbonization in step (d”) may be performed under a flow rate condition of an inert gas, preferably argon, of 0.1 to 30 ml / min, preferably 0.1 to 10 ml / min. When the carbonization is performed under this inert gas flow rate condition, the stabilized pitch can be sufficiently carbonized.

[0183] In a specific example of the present invention, the carbonization in step (d”) may be performed for 0.5 to 5 hours, preferably 1 to 3 hours. When the carbonization in step (d”) is performed for this period of time, the stabilized pitch can be sufficiently carbonized.

[0184] Meanwhile, since the description of the contents other than the above step (d”) may be the same as the description of the above step (d), a detailed description will be omitted.

[0185] Meanwhile, the pitch for manufacturing the soft carbon may be at least one of an isotropic pitch and an anisotropic pitch, and preferably, an anisotropic pitch may be more advantageous in achieving the purpose of the present invention.

[0186]

[0187] In a method for manufacturing a carbon / silicon-carbon composite according to an embodiment of the present invention, the obtained carbon / silicon-carbon composite may be crushed or pulverized and classified. Classification can achieve a uniform particle size distribution of the composite. Here, classification may be performed by dry classification, wet classification, or classification using a sieve.

[0188]

[0189] Negative active material

[0190] According to another embodiment of the present invention, a negative active material comprising the carbon / silicon-carbon composite is provided.

[0191] The negative electrode active material according to an embodiment of the present invention may further include a carbon-based negative electrode material, specifically a graphite-based negative electrode material, in addition to the carbon / silicon-carbon composite. For example, the negative electrode active material may be obtained by mixing the carbon / silicon-carbon composite according to an embodiment of the present invention with a carbon-based negative electrode material, for example, a graphite-based negative electrode material.

[0192] Here, the carbon-based negative electrode material may include, but is not particularly limited to, at least one selected from the group consisting of natural graphite, artificial graphite, soft carbon, hard carbon, mesocarbon, carbon fiber, carbon nanotube, pyrolytic carbon, coke, organic polymer compound sintered body, and carbon black.

[0193] The content of the carbon-based negative electrode material in the negative electrode active material according to an embodiment of the present invention may be 2 to 80 wt%, preferably 5 to 70 wt%, and more preferably 30 to 70 wt%, based on the total weight of the negative electrode active material.

[0194] The negative active material according to an embodiment of the present invention can be effectively used in manufacturing a secondary battery, specifically, a negative electrode of a lithium secondary battery and a negative electrode of an all-solid-state battery.

[0195]

[0196] All-solid-state batteries

[0197] According to another embodiment of the present invention, an all-solid-state battery is provided comprising a solid electrolyte interphase (SEI) film comprising the carbon / silicon-carbon composite.

[0198] The above-described all-solid-state battery may be an all-solid-state battery including a positive electrode, a negative electrode, and a solid electrolyte between the positive electrode and the negative electrode, and the negative electrode may include a negative electrode active material layer, and may include a solid electrolyte interphase (SEI) film including the carbon / silicon-carbon composite described above on at least a portion of the negative electrode active material particles of the negative electrode active material layer.

[0199] Meanwhile, the above-described negative electrode active material particles may be carbon-based negative electrode materials, and in this case, since the content may be the same as that described in the content of the above-described negative electrode active material, the related description will be omitted.

[0200] In addition, in addition to the negative active material particles and SEI film of the above-mentioned all-solid-state battery, the negative electrode configuration, positive electrode configuration, and solid electrolyte configuration can be applied to known all-solid-state battery configurations, and thus the present invention does not specifically limit them.

[0201]

[0202] The present invention is described in more detail by the following examples. The following examples are merely illustrative of the present invention and are not intended to limit the scope of the present invention.

[0203] [Example]

[0204] <Preparation Example 1>

[0205] 300 g of petroleum residual oil (YNCC, HTC PFO (pyrolysis fuel oil)) was placed in a reactor equipped with a stirrer, and pyrolysis and polycondensation were performed at 450°C for 3 hours while supplying nitrogen at a flow rate of 100 ml / min. During this time, the stirrer was rotated at a speed of 200 rpm to mix the reactants. The polymerized pitch was solidified and pelletized to obtain solid pitch pellets with an average particle size (particle size distribution D50) of 1–30 mm.

[0206] The solid pitch pellets obtained above were pulverized to produce pitch particles with a particle size distribution D50 of 200 μm, and then placed in a rotary kiln having three zones to sequentially perform stabilization, carbonization, and activation. The conditions for stabilization, carbonization, and activation are as shown in Table 1 below.

[0207] The specific surface area of ​​the carbon support was measured using a Belsorp mini II according to ASTM D4820-93. The tap density of the carbon support was measured using a tap density analyzer (Electrolab, ETD-1020x) according to ASTM B527. The particle size distribution of the carbon support was measured using a particle size analyzer (Horiba, Laser Particle Analyzer, LA-960V2) according to ASTM E112. The results are shown in Table 1.

[0208] Step Condition Standard Example Stabilization temperature (℃) 300 hours (hr) 3 Atmospheric air Carbonization temperature (℃) 900 hours (hr) 1 Atmospheric nitrogen Activation temperature (℃) 900 hours (hr) 3 Water vapor flow rate (㎖ / min) 200 Support physical properties Particle size distribution D50 (㎛) 200 Specific surface area (㎡ / g) 1409.1 Tap density (g / ㎖) 0.44

[0209] The porous carbon support of Preparation Example 1 was pulverized with a pulverizer (NETZSCH, Air Jet Mill) to obtain a fine powder of the porous carbon support with a particle size distribution D50 of 7 ㎛. Next, 15 g of the fine powder of this porous carbon support was placed in a rotary kiln, and silane (SiH4) gas was injected to form a silicon layer on the porous carbon support, thereby producing a carbon / silicon composite. The silicon layer formation conditions and the physical properties of the carbon support after the silicon layer formation are shown in Table 2 below.

[0210] Step-by-step example Silicon layer formation conditions Batch (g) 15 Pressure Atmospheric pressure Temperature (℃) 475 Time (min) 120 Carbon-silicon composite properties after silicon layer formation Particle size distribution D50 (㎛) 8.9 Specific surface area (㎡ / g) 10.4 Tap density (g / ㎖) 0.6

[0211]

[0212] <Example 1-1: Preparation of carbon / silicon-polymer composite>

[0213] A carbon / silicon-polymer composite was prepared using a reactor schematically illustrated in Fig. 1. 5 g of the carbon / silicon composite prepared according to Preparation Example 1 was evenly spread and placed on a circular silicon wafer. Vaporized monomers and an initiator were supplied into the reactor chamber through an inlet to form a polymer thin film (pDMAMS) on the surface of the porous carbon support of the carbon / silicon composite, inside the pores, and on the surface of the silicon. The specific conditions of the materials and process used in Example 1-1 are as follows.

[0214] - Carbon / silicon-polymer composite: Preparation example 1

[0215] - Monomer: Dimethylaminomethyl styrene (Acros, 90%)

[0216] - Initiator: di-t-butyl peroxide (Aldrich, 98%)

[0217] - Average initiator supply flow rate: 0.26 sccm

[0218] - Average monomer feed flow rate: 0.425 sccm

[0219] - Filament temperature: 140℃

[0220] - Pressure inside the reactor chamber: 160 mTorr

[0221] - Surface temperature of the reactor mounting part (silicon wafer): 35℃

[0222] - Polymer film thickness: 10 nm

[0223]

[0224] <Example 1-2>

[0225] A carbon / silicon-polymer composite was manufactured in the same manner as in Example 1-1, but the following details were changed to form a polymer thin film (pPFDMA) on the surface of the porous carbon support, inside the pores, and on the surface of the silicon of the carbon / silicon composite, thereby manufacturing a carbon / silicon-polymer composite.

[0226] - Monomer: 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluorodecyl methacrylate (PFDMA) (Aldrich, 80%)

[0227] - Initiator: di-t-butyl peroxide (Aldrich, 98%)

[0228] - Average initiator supply flow rate: 0.26 sccm

[0229] - Average monomer feed flow rate: 0.425 sccm

[0230] - Filament temperature: 140℃

[0231] - Pressure inside the reactor chamber: 80 mTorr

[0232] - Surface temperature of the reactor mounting part (silicon wafer): 38℃

[0233] - Polymer film thickness: 14 nm

[0234]

[0235] Experimental Example 1

[0236] (1) X-ray photoelectron spectroscopy

[0237] For Preparation Example 1, Examples 1-1 and 1-2, the elements on the particle surface were analyzed using X-ray photoelectron spectroscopy (XPS) (Multilab 2000, Thermo). The results are shown in Fig. 3.

[0238] As a result, in the case of the preparation example before the polymer thin film was formed in FIGS. 3a to 3d, no fluorine or nitrogen was measured, but it was confirmed that nitrogen was measured when the pDMAMS polymer thin film was formed (Example 1-1), and a significant amount of fluorine was measured when the pPFDMA polymer thin film was formed (Example 1-2). Therefore, it can be seen that a carbon / silicon-polymer composite in which a nitrogen- or fluorine-containing polymer thin film was formed on the surface of the porous carbon support, inside the pores, and on the surface of the silicon was manufactured by the manufacturing method of the present invention.

[0239]

[0240] <Preparation Example 2>

[0241] As Preparation Example 2, graphite having a particle size distribution D50 of 17.08 ㎛ was prepared.

[0242]

[0243] <Example 2-1>

[0244] The same procedure as in Example 1-1 was followed, but the carbon / silicon composite according to Preparation Example 1 was changed to graphite according to Preparation Example 2 to produce a graphite-polymer (pDMAMS) composite.

[0245]

[0246] <Example 2-2>

[0247] The same procedure as in Example 1-2 was followed, but the carbon / silicon composite according to Preparation Example 1 was changed to graphite according to Preparation Example 2 to produce a graphite-polymer (pPFDMA) composite.

[0248]

[0249] Experimental Example 2

[0250] (1) X-ray photoelectron spectroscopy

[0251] For Preparation Example 2, Examples 2-1 and 2-2, the elements on the particle surface were analyzed using X-ray photoelectron spectroscopy (XPS) (Multilab 2000, Thermo). The results are shown in Fig. 4.

[0252] As a result, in the case of Preparation Example 2 before the polymer thin film was formed in FIGS. 4a to 4d, no fluorine or nitrogen was measured, but it was confirmed that nitrogen was measured when the pDMAMS polymer thin film was formed (Example 2-1), and a significant amount of fluorine was measured when the pPFDMA polymer thin film was formed (Example 2-2). Therefore, it can be seen that a graphite-polymer composite in which a nitrogen- or fluorine-containing polymer thin film was formed on the graphite surface was manufactured by the manufacturing method of the present invention.

[0253]

[0254] <Preparation Example 3>

[0255] 15 g of graphite with a particle size distribution D50 of 17.08 μm was placed in a rotary kiln, and silane (SiH4) gas was injected to form a silicon layer on the graphite surface to manufacture a graphite / silicon composite. The conditions for forming the silicon layer are as shown in Table 2 above.

[0256]

[0257] <Example 3-1>

[0258] The same procedure as in Example 1-1 was followed, but the carbon / silicon composite according to Preparation Example 1 was changed to a graphite / silicon composite according to Preparation Example 3 to produce a graphite / silicon-polymer (pDMAMS) composite.

[0259]

[0260] <Example 3-2>

[0261] The same procedure as in Example 1-2 was followed, but the carbon / silicon composite according to Preparation Example 1 was changed to a graphite / silicon composite according to Preparation Example 3 to produce a graphite / silicon-polymer (pPFDMA) composite.

[0262]

[0263] Experimental Example 3

[0264] (1) X-ray photoelectron spectroscopy

[0265] For Preparation Example 3, Examples 3-1 and 3-2, the elements on the particle surface were analyzed using X-ray photoelectron spectroscopy (XPS) (Multilab 2000, Thermo). The results are shown in Fig. 5.

[0266] As a result, in the case of Preparation Example 3 before the polymer thin film was formed in FIGS. 5a to 5d, nitrogen was not measured and only a trace amount of fluorine was measured, but it was confirmed that nitrogen was measured when the pDMAMS polymer thin film was formed (Example 3-1), and a significant amount of fluorine was measured when the pPFDMA polymer thin film was formed (Example 3-2). Therefore, it can be seen that a graphite / silicon-polymer composite in which a nitrogen- or fluorine-containing polymer thin film was formed on the surface of the graphite / silicon composite was manufactured by the manufacturing method of the present invention.

[0267]

[0268] <Example 1-3>

[0269] A carbon / silicon-polymer composite was manufactured in the same manner as in Example 1-1, but the following details were changed to form a polymer thin film (pDVB) on the surface of the porous carbon support, inside the pores, and on the surface of the silicon of the carbon / silicon composite, thereby manufacturing a carbon / silicon-polymer composite.

[0270] - Monomer: Divinylbenzene (DVB)

[0271] - Initiator: di-t-butyl peroxide (Aldrich, 98%)

[0272] - Average initiator supply flow rate: 0.26 sccm

[0273] - Average monomer feed flow rate: 0.425 sccm

[0274] - Filament temperature: 140℃

[0275] - Pressure inside the reactor chamber: 450 mTorr

[0276] - Surface temperature of the reactor mounting part (silicon wafer): 23℃

[0277] - Polymer film thickness: 12 nm

[0278]

[0279] <Manufacturing Example 1: Manufacturing of a Carbon / Silicon-Carbon Composite>

[0280] The carbon / silicon-polymer composite manufactured according to Example 1-3 was heated to 250°C to oxidize the polymer for 30 minutes, and then heat-treated at 700°C for 1 hour in a 99.999% high-purity nitrogen (N2) environment to carbonize the polymer thin film of the carbon / silicon-polymer composite, thereby manufacturing a carbon / silicon-carbon composite. At this time, all heating rates were fixed at 10°C / min.

[0281]

[0282] <Manufacturing Examples 2 to 3>

[0283] Carbon / silicon-carbon composites were manufactured in the same manner as in Manufacturing Example 1, but the heat treatment temperatures were changed to 400°C and 600°C, respectively.

[0284]

[0285] Experimental Example 4

[0286] FT-IR analysis was performed on the composites according to Manufacturing Examples 1 to 3. As can be seen in the FT-IR spectra shown in Fig. 6, in Manufacturing Example 1 (heat treatment at 700°C), the peak disappeared, indicating that the polymer was carbonized.

[0287] In addition, Raman spectroscopy analysis was performed on the complexes according to Examples 1-3 and Manufacturing Example 1. As shown in Fig. 7, in the case of Manufacturing Example 1, the G band and D band can be observed, confirming that pDVB was carbonized.

[0288]

[0289] <Example 1-4>

[0290] A carbon / silicon-polymer composite was manufactured in the same manner as in Example 1-1, but the following details were changed to form a polymer thin film (pPFDA) on the surface of the porous carbon support, inside the pores, and on the surface of the silicon of the carbon / silicon composite, thereby manufacturing a carbon / silicon-polymer composite.

[0291] - Monomer: PFDA (perfluorodecanoic acid)

[0292] - Initiator: di-t-butyl peroxide (Aldrich, 98%)

[0293] - Average initiator supply flow rate: 0.26 sccm

[0294] - Average monomer feed flow rate: 0.425 sccm

[0295] - Filament temperature: 140℃

[0296] - Pressure inside the reactor chamber: 80 mTorr

[0297] - Surface temperature of the reactor mounting part (silicon wafer): 38℃

[0298] - Polymer film thickness: 14 nm

[0299]

[0300] Experimental Example 5

[0301] Examples 1-4 were observed using a transmission electron microscope (TEM)-energy dispersive spectrometer (EDS) (Tecnai G2 F30 S-Twin, FEI company). The EDS analysis results are shown in Fig. 8a, and the TEM analysis results are shown in Fig. 8b.

[0302] As a result, from the EDS analysis results of Fig. 8a, it was confirmed that a polymer thin film was uniformly formed on the surface through the detection of F in Example 1-4.

[0303] In addition, from the TEM image of Fig. 8b, it was confirmed that a uniform polymer thin film with an average thickness of 10 nm was formed in Example 1-4.

[0304] Therefore, it was qualitatively confirmed that a uniform polymer thin film was formed on a carbon support by the manufacturing method of the present invention.

[0305]

[0306] <Manufacturing Example 4: Manufacturing of a Carbon / Silicon-Carbon Composite>

[0307] The same procedure as in Manufacturing Example 1 was followed, but the heat treatment temperature was changed to 400°C, and the carbon / silicon-polymer composite of Example 1-3 was changed to the carbon / silicon-polymer composite of Example 1-4 to manufacture a carbon / silicon-carbon composite.

[0308]

[0309] Experimental Example 6

[0310] For Examples 1-4, Manufacturing Example 4, and Preparation Example 1, the elements on the particle surface were analyzed using X-ray photoelectron spectroscopy (XPS) (Multilab 2000, Thermo). The results are shown in Fig. 9.

[0311] As a result, as shown in Fig. 9, in Manufacturing Example 4, which performed carbonization, it was confirmed that the polymer thin film was carbonized, and the F content was reduced compared to Examples 1-4.

[0312] In addition, when comparing the carbon / silicon composite according to Preparation Example 1 and the carbon / silicon-carbon composite according to Manufacturing Example 4 as shown in FIG. 9, it was confirmed that Manufacturing Example 4 contained more carbon than Preparation Example 1.

[0313]

[0314] Experimental Example 7: Electrochemical Evaluation of Secondary Batteries

[0315] Half coin cells were manufactured using each of the previously manufactured Manufacturing Example 4, Examples 1-4, and Preparation Example 1 as negative electrode materials.

[0316] Specifically, a slurry was prepared by mixing the composite: conductive material: binder in a ratio of 8:1:1. At this time, the composite was prepared using each of Manufacturing Example 4, Examples 1-4, and Preparation Example 1, the conductive material was super-P, and the binder was prepared by mixing styrene butadiene rubber (SBR) and sodium carboxymethyl cellulose (CMC) in a weight ratio of 5:5.

[0317] Next, the slurry was uniformly applied to copper foil and dried in an 80°C oven for 1 hour. After the primary drying, the slurry was roll-pressed and dried in a 120°C vacuum oven for 6 hours and 30 minutes to manufacture a negative electrode plate.

[0318] A half coin cell was manufactured using the above-mentioned negative electrode and lithium foil as a counter electrode. A porous polyethylene film was used as a separator, and a CR2032 half coin cell (half cell) was manufactured under the conditions shown in Table 3 below.

[0319] The electrolyte was prepared by dissolving 1.3 M LiPF6 in a solvent containing ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC) in a volume ratio of 3:5:2, and dissolving 10 wt% fluoro-ethylene carbonate (FEC), 0.2 wt% lithium tetrafluoroborate (LiBF4), 0.5 wt% vinylene carbonate (VC), and 1 wt% propane sulton (PS) as additives (see Table 3).

[0320] Composition (AM:CM:BM) 8:1:1 Area capacity (mAh / cm 2 )1 Electrolyte 1.3M LiPF6 EC / EMC / DMC 3:5:2, FFC 10%, LiBF4 0.2%, 0.5% VC, 1% PS Cut-off voltage (V) Formation: 0.005 ~ 1.5, Cycle test: 0.005 ~ 1.5 C-rate (C) Formation: 0.1 ~ 0.1. 0.01 C cut-off (CV) at 0.005 V

[0321] In the above Table 3, AM, CM, and BM represent active materials (respectively, Manufacturing Example 4, Examples 1-4, and Preparation Example 1), conductors (Super P carbon black), and binders (styrene-butadiene rubber / carboxymethyl cellulose 5:5), respectively, and EC, EMC, DMC, FEC, VC, and PS represent ethylene carbonate, ethyl methyl carbonate, dimethyl carbonate, fluoroethylene carbonate, vinylene carbonate, and propane sultone, respectively.

[0322] Electrochemical analysis was performed on the manufactured half coin cell under the following conditions.

[0323] Cut off voltage (V): 0.005 - 1.5V (Formation), 0.005 - 1.2V(Cycle)

[0324] Formation C-rate (C): 0.1C lithiation, 0.1C delithiation

[0325] Cycle C-rate (C): 0.5C lithiation, 0.5C delithiation

[0326] Discharge capacity (mAh / g) ICE (%) Cycle Retention (%) Cycle Manufacturing Example 4192788.742.150 Example 1-4196286.131.850 Preparation Example 11724869.750

[0327] As can be seen in Table 4 above, the coin cell using Preparation Example 4, which is a carbon / silicon-carbon composite of the present invention, has a higher initial coulombic efficiency (ICE) and a significantly superior cycle maintenance rate compared to the coin cell using Examples 1-4, which is a carbon / silicon-polymer composite, thereby showing the effect of enabling stable charge / discharge. It was confirmed that the coin cell using Preparation Example 1, which is a carbon / silicon composite, has a significantly higher initial coulombic efficiency (ICE) and a significantly superior cycle maintenance rate compared to the coin cell using Preparation Example 1, which is a carbon / silicon composite, thereby showing the effect of enabling stable charge / discharge.

[0328]

[0329] Although one embodiment of the present invention has been described above, the spirit of the present invention is not limited to the embodiment presented in this specification, and a person skilled in the art who understands the spirit of the present invention will be able to easily propose other embodiments by adding, changing, deleting, or adding components within the scope of the same spirit, but this will also be considered to fall within the spirit of the present invention.

Claims

1. Carbon support; Silicon disposed including the surface of the above carbon support; and A carbon / silicon-carbon composite comprising a carbon thin film disposed including the surface of the carbon support and the surface of the silicon.

2. In paragraph 1, The above carbon support is a carbon / silicon-carbon composite comprising a nonporous carbon support comprising at least one of hard carbon and soft carbon.

3. In paragraph 1, The above carbon support is a porous carbon support, The above silicon is arranged on the surface and inside the pores of the porous carbon support, The carbon film is a carbon / silicon-carbon composite disposed on the surface of the porous carbon support, inside the pores, and on the surface of the silicon.

4. In paragraph 3, The above porous carbon support is a carbon / silicon-carbon composite having a volume ratio of mesopores with a pore size of 2 to 50 nm of 10 to 80% based on the total pore volume.

5. In paragraph 3, The above porous carbon support is a carbon / silicon-carbon composite having a BET specific surface area of ​​300 to 3,000 m2 / g, a tap density of 0.05 to 0.5 g / ㎖, and a particle size distribution D50 of 1 to 20 ㎛.

6. In paragraph 1, A carbon / silicon-carbon composite wherein the silicon is 5 to 80 wt% of the total weight of the carbon / silicon-carbon composite.

7. In paragraph 1, The carbon film is a carbon / silicon-carbon composite in which the carbon film accounts for 0.5 to 30 wt% of the total weight of the carbon / silicon-carbon composite. 8.(1) A step of manufacturing a carbon / silicon composite by forming silicon including the surface of a carbon support; (2) a step of manufacturing a carbon / silicon-polymer composite by forming a polymer thin film through an initiator-based chemical vapor deposition (iCVD) method including the surface of the carbon support and the surface of the silicon of the carbon / silicon composite; and (3) A method for producing a carbon / silicon-carbon composite, comprising: a step of producing a carbon / silicon-carbon composite by carbonizing the polymer thin film of the carbon / silicon-polymer composite.

9. In paragraph 8, step (2) is, (2-1) Step of supplying a carbon / silicon composite into a reactor; (2-2) A step of supplying monomers and initiators to the reactor to which the carbon / silicon composite has been supplied; and (2-3) A method for producing a carbon / silicon-carbon composite, comprising: a step of activating the initiator to polymerize the monomer, thereby forming a polymer thin film including the surface of the carbon support and the surface of the silicon of the carbon / silicon composite.

10. In paragraph 8, The above polymer thin film is a method for manufacturing a carbon / silicon-carbon composite having a thickness of 1 nm to 10 ㎛.

11. In paragraph 9, A method for producing a carbon / silicon-carbon composite, wherein in the above 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.

12. In paragraph 9, The above initiator is activated through a predetermined heat treatment, A method for manufacturing a carbon / silicon-carbon composite, wherein the above heat treatment is performed at a temperature of 135 to 350°C.

13. In paragraph 9, The above steps (2-3) are a method for manufacturing a carbon / silicon-carbon composite, which is performed in a vacuum state at a pressure of 50 to 1,000 mTorr for 10 minutes to 6 hours.

14. In paragraph 8, A method for manufacturing a carbon / silicon-carbon composite, wherein the carbonization in step (3) above is performed by heat treatment at a temperature of 400 to 1,400°C.

15. Carbon / silicon-carbon composite according to any one of claims 1 to 7; and A negative electrode active material comprising a carbon-based negative electrode material.

16. An all-solid-state battery comprising a SEI (Solid Electrolyte Interphase) film comprising a carbon / silicon-carbon composite according to any one of claims 1 to 7.

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