Carbon / silicon-polymer composite and method for manufacturing same

Abstract

The present invention relates to a carbon / silicon-polymer composite and a method for manufacturing same. A carbon / silicon-polymer composite according to an embodiment of the present invention has excellent thickness uniformity of a polymer thin film, while the polymer thin film hardly affects electrical conductivity and lithium-ion conductivity. Therefore, when used as a negative electrode material, the carbon / silicon-polymer composite can act as a stable solid electrolyte interface layer while maintaining high specific capacity and Coulombic efficiency, and thus can suppress degradation in battery performance and lifespan.

Description

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

[0001] The present invention relates to a carbon / silicon-polymer composite, and more particularly, to a carbon / silicon-polymer composite and a method for producing the same.

[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 material for secondary batteries.

[0004] Recently, attempts have been made to use silicon-based anode 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 cathode 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 anode 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] [Prior Art Literature]

[0008] [Patent Document]

[0009] (Patent Document 0001) Japanese Patent Publication No. 4393610

[0010] An object of the present invention is to provide a carbon / silicon-polymer composite in which a polymer film is formed on a carbon-silicon composite coated with silicon on the pores and / or surface of a porous carbon support having controlled pore characteristics.

[0011] Another object of the present invention is to provide a method for producing the carbon / silicon-polymer composite.

[0012] Another object of the present invention is to provide a negative electrode material comprising the carbon / silicon-polymer composite.

[0013] The present invention provides a carbon / silicon-polymer composite comprising a porous carbon support, a carbon-silicon composite including silicon disposed on the surface and inside the pores of the porous carbon support, and a polymer thin film disposed on the surface of the porous carbon support, inside the pores, and on the surface of the silicon.

[0014] According to one embodiment of the present invention, 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 an average particle diameter of 1 to 20 ㎛.

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

[0016] Additionally, the polymer thin film may be 1 to 30 wt% of the total weight of the carbon / silicon-polymer composite.

[0017] Additionally, the polymer thin film may have a thickness of 1 to 450 nm.

[0018]

[0019] In addition, the present invention provides a method for producing a carbon / silicon-polymer composite, comprising the steps of (1) forming silicon on the surface and inside the pores of a porous carbon support to produce a carbon-silicon composite, and (2) forming a polymer thin film on the surface of the porous carbon support, inside the pores, and the surface of the silicon of the carbon-silicon composite through an initiator-based chemical vapor deposition (iCVD) method to produce a carbon / silicon-polymer composite.

[0020] According to one embodiment of the present invention, the step (2) may include the step of (2-1) supplying a carbon-silicon composite into a reactor, the step of (2-2) supplying a monomer and an initiator to the reactor supplied with the carbon-silicon composite, and the step of (2-3) activating the initiator to polymerize the monomer, thereby forming a polymer thin film on the surface of the porous carbon support of the carbon-silicon composite, inside the pores, and on the surface of the silicon.

[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]

[0025] In addition, the present invention provides an anode material comprising the above-described carbon / silicon-polymer composite and a carbon-based anode material.

[0026]

[0027] In addition, the present invention provides an all-solid-state battery including a SEI (Solid Electrolyte Interphase) film comprising the above-described carbon / silicon-polymer composite.

[0028]

[0029] In addition, the present invention provides a lithium ion battery including the above-described negative electrode material.

[0030] The carbon / silicon-polymer composite according to an embodiment of the present invention has excellent thickness uniformity of the polymer thin film, and the polymer thin film has little effect on electrical conductivity and lithium ion conductivity, so that when used as an anode material, it can act as a stable solid electrolyte interfacial layer while maintaining high specific power and coulombic efficiency, thereby suppressing degradation of battery performance and lifespan.

[0031] 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.

[0032] Figure 2 is a schematic diagram of a carbon / silicon-polymer composite according to one embodiment of the present invention.

[0033] FIG. 3 shows the results of XPS (X-ray Photoelectron Spectroscopy) analysis of a carbon-silicon composite (FIG. 3a) according to Comparative Example 1 of the present invention and carbon / silicon-polymer composites (FIG. 3b to FIG. 3e) according to Examples 1 to 4.

[0034] FIG. 4 is a TEM image of a carbon-silicon composite according to Comparative Example 1 of the present invention (FIG. 4a), and carbon / silicon-polymer composites according to Examples 1, 2, and 5 (FIG. 4b, FIG. 4c, and FIG. 4d).

[0035] FIG. 5 is a graph showing electrochemical evaluation results (charge / discharge efficiency, ICE, and capacity retention) for carbon / silicon-polymer composites according to Examples 1 to 6 of the present invention and carbon-silicon composites according to Comparative Example 1.

[0036] 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.

[0037] As used herein, the term “comprising” means that other components may be included unless otherwise stated.

[0038] 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.

[0039] 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.

[0040] The present invention will be described in more detail below.

[0041] carbon / silicon-polymer composites

[0042] As illustrated in FIG. 2, according to one embodiment of the present invention, a carbon / silicon-polymer composite (10) is provided, which includes a porous carbon support (11), a carbon-silicon composite including silicon (12) disposed on the surface and inside the pores of the porous carbon support (11), and a polymer thin film (13) disposed on the surface of the porous carbon support (11), inside the pores, and on the surface of the silicon (12).

[0043] Hereinafter, each component of a carbon / silicon-polymer composite (10) according to one embodiment of the present invention will be described.

[0044] porous carbon support

[0045] A carbon / silicon-polymer composite (10) according to an embodiment of the present invention includes a porous carbon support (11).

[0046] 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 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.

[0047] 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 may be deposited on the outside of the particles.

[0048] In addition, the porous carbon support (11) may have a tap density of 0.05 to 0.5 g / ml. Preferably, the porous carbon support (11) may have a tap density of 0.05 to 0.3 g / ml, more preferably, a tap density of 0.1 to 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 deposition of the silicon source and formation of the polymer thin film, which may result in a decrease in yield, and when the tap density of the porous carbon support exceeds 0.5 g / ml, uniform coating may be difficult during deposition of the silicon source and formation of the polymer thin film.

[0049] And, the porous carbon support (11) may have an average particle size of 1 to 20 ㎛. Preferably, the porous carbon support (11) may have an average particle size of 3 to 20 ㎛, more preferably an average particle size of 3 to 10 ㎛. When the average particle size of the porous carbon support is less than 1 ㎛, the silicon source and the monomer and initiator for forming the polymer thin film cannot sufficiently penetrate into the pores and are deposited / adsorbed only to the outside of the particles in large amounts, and when the average particle size of the porous carbon support exceeds 20 ㎛, it is difficult for silicon and polymer to be sufficiently formed in the pores.

[0050] Since the carbon / silicon-polymer 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-polymer composite (10) is used as a negative electrode material, it has excellent electrical conductivity and can relieve stress due to volume expansion of silicon.

[0051] silicone

[0052] A carbon / silicon-polymer composite (10) according to an embodiment of the present invention includes silicon (12) arranged on the surface and inside the pores of the porous carbon support (11).

[0053] By arranging the porous carbon support (11) and silicon (12) in the carbon / silicon-polymer composite (10) according to the present invention as described above, the negative electrode material manufactured from the carbon / silicon-polymer composite (10) according to the present invention can have a high electrical capacity while minimizing the influence due to volume expansion of silicon.

[0054] At this time, since the silicon (12) plays a role in charging lithium, when the carbon / silicon-polymer composite (10) according to the embodiment of the present invention is used as a negative electrode material, the silicon can act as a main negative electrode material.

[0055] 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.

[0056] The particle size of the silicon may be selected so that the carbon / silicon-polymer composite according to an embodiment of the present invention is suitable for use as a negative electrode material. Specifically, the average particle size of the silicon may be 10 nm to 50 μm, and preferably 10 nm to 25 μm. As the silicon satisfies the average particle size range, it may be more advantageous in achieving the purpose of the present invention.

[0057] Meanwhile, the silicon (12) may be 5 to 80 wt% of the total weight of the carbon / silicon-polymer 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-polymer 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.

[0058] 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.

[0059] 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.

[0060] polymer thin films

[0061] A carbon / silicon-polymer composite (10) according to an embodiment of the present invention includes a polymer thin film (13) disposed on the surface of the porous carbon support (11), inside the pores, and on the surface of the silicon (12).

[0062] In a carbon / silicon-polymer composite according to an embodiment of the present invention, a polymer thin film on the carbon-silicon composite is formed by an initiator-based chemical vapor deposition (iCVD) method described below.

[0063] 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 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.

[0064] 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 (GMA), divinylbenzene (DVB), diethylene glycol divinyl ether, diethylene glycol diacrylate (DEGDA), ethylene glycol dimethacrylate, dimethylaminoethyl methacrylate, methacrylic acid, and 1,3-Dietenyl-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-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, 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,11-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.

[0065] 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.

[0066] In a specific embodiment of the present invention, the thickness of the polymer thin film may be 1 to 450 nm, preferably 1 to 200 nm, more preferably 1 to 100 nm, and even more preferably 1 to 50 nm. When the thickness of the polymer thin film is within this range, it can act as a stable solid electrolyte interfacial layer between silicon and the electrolyte without significantly affecting the electrical conductivity and lithium ion conductivity of the negative electrode material, thereby suppressing the reduction in battery life.

[0067] Meanwhile, the polymer thin film may be 1 to 30 wt% of the total weight of the carbon / silicon-polymer composite (10) according to the present invention, and preferably 1 to 20 wt%. If the polymer thin film is less than 1 wt% of the total weight of the carbon / silicon-polymer composite, it may not function as a stable solid electrolyte interfacial layer, and if the silicon exceeds 30 wt%, it may rather become a factor that hinders the reaction on the silicon surface.

[0068]

[0069] Method for manufacturing carbon / silicon-polymer composites

[0070] A carbon / silicon-polymer composite according to one embodiment of the present invention is manufactured by a manufacturing method including the steps of (1) forming silicon on the surface and inside the pores of a porous carbon support to manufacture a carbon-silicon composite, and (2) forming a polymer thin film on the surface of the porous carbon support, inside the pores, and the surface of the silicon of the carbon-silicon composite through an initiator-based chemical vapor deposition (iCVD) method to manufacture a carbon / silicon-polymer composite.

[0071] Hereinafter, each step of a method for manufacturing a carbon-silicon / polymer composite according to one embodiment of the present invention is described.

[0072] (1) Step

[0073] In step (1) above, silicon is formed on the surface and inside the pores of the porous carbon support to manufacture a carbon-silicon composite.

[0074] In a specific embodiment of the present invention, the step of forming silicon on the surface and within the pores of the porous carbon support can 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 can be formed on the surface and within the pores of the porous carbon support by supplying a silicon source to the porous carbon support and performing CVD.

[0075] 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.

[0076] 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. In addition, the CVD can be performed at atmospheric pressure, and may be performed under a low vacuum of about 10 Torr if necessary. In addition, the deposition can be performed under a silane (SiH4) gas atmosphere of, for example, 50 sccm or more and 500 sccm or less.

[0077] (2) Step

[0078] In the above step (2), a polymer thin film is formed on the surface of the porous carbon support of the carbon-silicon composite, inside the pores, and on the surface of the silicon through an initiator-based chemical vapor deposition (iCVD) method to manufacture a carbon / silicon-polymer composite.

[0079] 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 to be 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.

[0080] Meanwhile, according to one embodiment of the present invention, the step (2) may include the step of (2-1) supplying a carbon-silicon composite into a reactor, (2-2) supplying a monomer and an initiator to the reactor to which the carbon-silicon composite has been supplied, and (3) activating the initiator to polymerize the monomer, thereby forming a polymer thin film on the surface of the porous carbon support of the carbon-silicon composite, inside the pores, and on the surface of the silicon.

[0081] FIG. 1 schematically illustrates a process for forming a polymer thin film on the surface of a porous carbon support, inside the pores, and on the surface of the silicon using an initiator-assisted chemical vapor deposition (iCVD) method according to an embodiment of the present invention. Referring to FIG. 1, a method for manufacturing a carbon / silicon-polymer composite according to an embodiment of the present invention will be described.

[0082] Step (2-1)

[0083] In the above step (2-1), a carbon-silicon composite is supplied into the reactor.

[0084] 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.

[0085] In a specific embodiment of the present invention, the reactor (1000) may include a chamber (100), a mounting portion (200), an inlet (300), an outlet (400), and a heating portion (500).

[0086] The above carbon-silicon composite may be placed on a mounting portion (200) provided at the bottom of the chamber (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 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.

[0087] The above 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 thin film to be evenly formed on the carbon-silicon composite in step (2-3) described below, but is not particularly limited thereto.

[0088] Step (2-2)

[0089] In the above step (2-2), monomers and initiators are supplied to the reactor.

[0090] 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 (1000).

[0091] 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.

[0092] 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.

[0093] 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.

[0094] 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.

[0095] Step (2-3)

[0096] In the above step (2-3), the initiator is activated to polymerize the monomer, thereby forming a polymer thin film on the surface of the porous carbon support of the carbon-silicon composite, inside the pores, and on the surface of the silicon.

[0097] First, the initiator (I) supplied into the chamber (100) of the reactor (1000) 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.

[0098] Free radicals (I) generated from the above initiator * ) and monomer (M) move to the bottom of the chamber and are adsorbed on the surface of the porous carbon support, inside the pores and on the surface of the silicon of the carbon-silicon composite accommodated in the mounting portion (200). The monomer adsorbed on the surface of the porous carbon support, inside the pores and on the surface of the silicon of the carbon-silicon composite is free radical (I * ) activated by (M * ) and polymerization proceeds 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.

[0099] 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).

[0100] 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 (1000) 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.

[0101] 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.

[0102] 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.

[0103] 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, etc., the molecular weight, thickness, composition, deposition rate, etc. of the polymer thin film can be easily controlled.

[0104] Preliminary stage

[0105] Meanwhile, according to one embodiment of the present invention, the method for producing the carbon / silicon-polymer 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.

[0106] In the above step (a), pitch can be synthesized by thermal decomposition and polycondensation of petroleum-based raw materials.

[0107] 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 (RFCC-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.

[0108] 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.

[0109] 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.

[0110] 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.

[0111] 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.

[0112] 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.

[0113] 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.

[0114] 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.

[0115] 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.

[0116] 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.

[0117] 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%.

[0118] 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.

[0119] 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.

[0120] 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.

[0121] 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.

[0122] First, in the case of the pellet-shaped pitch, the pitch (liquid) obtained in step (a) is solidified, for example, by extrusion and cooling, and pelletized into a desired size to obtain a solid pitch pellet (pellet-shaped pitch). The process of extruding, cooling, and pelletizing the liquid pitch to obtain a solid pitch pellet 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.

[0123] The pitch pellets (pitch in pellet form) 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 pitch pellets (pitch in pellet form) is within this range, a porous carbon support can be manufactured through stabilization, carbonization, and activation described below without separately pulverizing the pitch pellets (pitch in pellet form).

[0124] 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. Through crushing or pulverization, the pitch pellets (pellet-shaped pitch) can be further finely divided, and through classification, the particle size distribution of the pitch pellets (pellet-shaped pitch) can be made uniform. Here, the classification can be dry classification, wet classification, classification using a sieve, etc. By crushing or pulverizing and classification, a powdered pitch having an average particle size of 50 to 500 μm can be obtained.

[0125] And, in step (c), a step of stabilizing the pellet-shaped pitch or powder-shaped pitch can be performed.

[0126] First, the pellet-shaped pitch or powder-shaped pitch obtained in step (b) is subjected to primary oxidation to stabilize the carbon structure of the pitch.

[0127] 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.

[0128] 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.

[0129] 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.

[0130] 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.

[0131] 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.

[0132] And, in step (d), the stabilized pitch is 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.

[0133] 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.

[0134] 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.

[0135] 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.

[0136] 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.

[0137] 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 carbonized body, thereby obtaining a porous carbon support.

[0138] 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.

[0139] 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.

[0140] 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.

[0141] 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.

[0142] 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.

[0143] 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.

[0144] In a specific embodiment of the present invention, the above steps (c) to (e) can be performed continuously in one device. In a preferred embodiment of the present invention, the above steps (c) to (e) can be performed continuously in one rotary kiln, but the device is not particularly limited thereto. By performing the above steps (c) to (e) continuously in one device, optimization of the process can be achieved.

[0145] 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 grounding, 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 grounding and classification treatment, a porous carbon support powder having an average particle diameter of 1 to 20 μm, a BET specific surface area of ​​300 to 3,000 m2 / g, and a tap density of 0.05 to 0.5 g / ml can be obtained. In addition, the porous carbon support powder has a volume ratio of mesopores having a pore size of 2 to 50 nm based on the total pore volume of 10 to 80%.

[0146] Meanwhile, in the case where the pitch in pellet form is stabilized, carbonized, and activated without further pulverizing the pitch in the above step (b) to obtain a porous carbon support, the carbon support may be pulverized (or further classified) to have an average particle size of 1 to 20 μm, but is not limited thereto.

[0147]

[0148] In a method for manufacturing a carbon / silicon-polymer composite according to an embodiment of the present invention, the obtained carbon / silicon-polymer composite can be pulverized or ground and classified. Classification can achieve a uniform particle size distribution of the composite. Here, classification can be performed by dry classification, wet classification, or classification using a sieve.

[0149]

[0150] cathode material

[0151] According to another embodiment of the present invention, a negative electrode material comprising the carbon / silicon-polymer composite is provided.

[0152] The negative electrode 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-polymer composite. For example, the negative electrode material may be obtained by mixing the carbon / silicon-polymer composite according to an embodiment of the present invention with a carbon-based negative electrode material, such as a graphite-based negative electrode material.

[0153] 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.

[0154] The content of the carbon-based negative electrode material in the negative electrode 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 material.

[0155] The negative electrode 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.

[0156]

[0157] lithium-ion batteries

[0158] According to another embodiment of the present invention, a lithium ion battery including the negative electrode material is provided.

[0159] The above lithium ion battery may include an electrolyte, a positive electrode, a negative electrode, and a separator between the positive electrode and the negative electrode, and includes the above-described negative electrode material as the negative electrode material.

[0160] In addition, in addition to the negative electrode material of the lithium ion battery, the negative electrode configuration, positive electrode configuration, electrolyte configuration, and separator configuration can be applied to known lithium ion battery configurations, and thus the present invention does not specifically limit them.

[0161]

[0162] All-solid-state batteries

[0163] 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-polymer composite.

[0164] 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 material layer, and may include an SEI (Solid Electrolyte Interphase) film including the above-described carbon / silicon-polymer composite on at least a portion of the negative electrode material particles of the negative electrode material layer.

[0165] Meanwhile, the above-described negative electrode 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 material, the related description will be omitted.

[0166] In addition, in addition to the negative electrode 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 therefore the present invention does not specifically limit them.

[0167]

[0168] [Example]

[0169] 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.

[0170]

[0171] <Preparation>

[0172] 300 g of petroleum residue 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 of 1–30 mm.

[0173] The solid pitch pellets obtained above were pulverized to produce pitch particles with an average particle size of 200 μm, and then placed in a rotary kiln with three zones to sequentially perform stabilization, carbonization, and activation. The conditions for stabilization, carbonization, and activation are as shown in Table 1 below.

[0174] 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 average particle size 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.

[0175] 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 properties Average particle size (㎛) 200 Specific surface area (㎡ / g) 1409.1 Tap density (g / ㎖) 0.44

[0176] The porous carbon support of the reference example was pulverized with a pulverizer (NETZSCH, Air Jet Mill) to obtain a fine powder of the porous carbon support with an average particle size 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.

[0177] 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 Average particle size (㎛) 8.9 Specific surface area (㎡ / g) 10.4 Tap density (g / ㎖) 0.6

[0178]

[0179] <Example 1: Preparation of a carbon / silicon-polymer composite>

[0180] 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 the above preparation example 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 (pDVB) on the surface of the porous carbon support of the carbon-silicon composite, inside the pores, and on the surface of the silicon. The average thickness of the formed polymer thin film was 10 nm. The specific conditions of the materials and process used in this Example 1 are as follows.

[0181] - Carbon / silicon-polymer composite: Preparation example

[0182] - Monomer: Divinylbenzene (DVB) (Divinylbenzene, Aldrich, technical grade, 80%)

[0183] - Initiator: di-t-butyl peroxide (Aldrich, 98%)

[0184] - Average initiator supply flow rate: 0.26 sccm

[0185] - Average monomer feed flow rate: 0.425 sccm

[0186] - Filament temperature: 140℃

[0187] - Response time: 1 hour

[0188] - Pressure inside the reactor chamber: 160 mTorr

[0189] - Surface temperature of the reactor mounting part (silicon wafer): 35℃

[0190]

[0191] <Example 2>

[0192] A carbon / silicon-polymer composite was manufactured in the same manner as in Example 1, but the following changes were made to form a polymer thin film (pDMAMS) on the surface of the porous carbon support, inside the pores, and on the surface of the silicon of the carbon / silicon-polymer composite, thereby manufacturing a carbon / silicon-polymer composite. The average thickness of the formed polymer thin film was 10 nm.

[0193] - Monomer: Dimethylaminomethyl styrene (Acros, 90%)

[0194]

[0195] <Example 3>

[0196] A carbon / silicon-polymer composite was manufactured in the same manner as in Example 1, but the following changes were made 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-polymer composite, thereby manufacturing a carbon / silicon-polymer composite. The average thickness of the formed polymer thin film was 10 nm.

[0197] - Monomer: 1H,1H,2H,2H-perfluorodecyl acrylate (Aldrich, 97%)

[0198] - Response time: 15 minutes

[0199] - Pressure inside the reactor chamber: 80 mTorr

[0200] - Surface temperature of the reactor mounting part (silicon wafer): 38℃

[0201]

[0202] <Example 4>

[0203] A carbon / silicon-polymer composite was manufactured in the same manner as in Example 1, but the following changes were made to form a polymer thin film (pGMA) on the surface of the porous carbon support, inside the pores, and on the surface of the silicon of the carbon / silicon-polymer composite, thereby manufacturing a carbon / silicon-polymer composite. The average thickness of the formed polymer thin film was 10 nm.

[0204] - Monomer: Glycidyl methacrylate (GMA) (Aldrich, 97%)

[0205] - Response time: 2 hours

[0206] - Pressure inside the reactor chamber: 80 mTorr

[0207] - Surface temperature of the reactor mounting part (silicon wafer): 38℃

[0208]

[0209] <Example 5>

[0210] A carbon / silicon-polymer composite was manufactured in the same manner as in Example 1, but the following changes were made 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-polymer composite, thereby manufacturing a carbon / silicon-polymer composite. The average thickness of the formed polymer thin film was 1 nm.

[0211] To control the thickness of the polymer thin film, the iCVD process reaction time was controlled to 10 min.

[0212]

[0213] <Example 6>

[0214] A carbon / silicon-polymer composite was manufactured in the same manner as in Example 1, but the following changes were made 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-polymer composite, thereby manufacturing a carbon / silicon-polymer composite. The average thickness of the formed polymer thin film was 500 nm.

[0215] To control the thickness of the polymer thin film, the iCVD process reaction time was controlled to 6 hours.

[0216]

[0217] <Comparative Example 1>

[0218] A carbon-silicon composite was prepared according to the preparation example.

[0219]

[0220] Experimental Example 1

[0221] (1) X-ray photoelectron spectroscopy analysis

[0222] For Examples 1 to 4 and Comparative 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. 3.

[0223] As a result, in the case of Comparative Example 1 (Fig. 3a) where a polymer film was not formed, only oxygen, carbon, and silicon were measured, and it was confirmed that the carbon ratio increased when a pDVB polymer film was formed (Example 1), nitrogen was confirmed to be measured when a pDMAMS polymer film was formed (Example 2), a significant amount of fluorine was confirmed to be measured when a pPFDA polymer film was formed (Example 3), and it was confirmed that the carbon ratio increased when a pGMA polymer film was formed (Example 4). Therefore, it can be seen that a carbon / silicon-polymer composite in which a carbon, nitrogen, or fluorine-containing polymer film was formed on the surface of a porous carbon support, inside the pores, and on the surface of the silicon was manufactured by the manufacturing method of the present invention.

[0224] (2) TEM image analysis

[0225] Examples 1, 2, 5, and Comparative Example 1 were observed using a transmission electron microscope (TEM) (Fig. 4).

[0226] As a result, in the case of Comparative Example 1 (Fig. 4a) where no polymer thin film was formed, no separate polymer thin film was observed, in the cases of Examples 1 (Fig. 4b) and 2 (Fig. 4c), a polymer thin film with a thickness of 10 nm was observed, and in the case of Example 5 (Fig. 4d), a polymer thin film with a thickness of 1 to 2 nm was observed. Through this, it was confirmed that a polymer thin film was well formed on the surface of the porous carbon support, inside the pores, and on the surface of the silicon by the manufacturing method of the present invention, and that the formed polymer thin film had a uniform thickness.

[0227]

[0228] <Experimental Example 2: Electrochemical Evaluation>

[0229] Half coin cells were manufactured using the composites of Examples 1 to 6 and Comparative Example 1, and then electrochemical evaluations were performed. The conditions for manufacturing the half coin cells are shown in Table 3, and the evaluation results are shown in Table 4 and Fig. 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, and EC, EMC, DMC, FEC, VC, and PS represent ethylene carbonate, ethyl methyl carbonate, dimethyl carbonate, fluoroethylene carbonate, vinylene carbonate, and propane sultone, respectively.

[0230] Composition (AM:CM:BM) 8:1:1 Areal capacity (mAh / cm2) 1 Electrolyte 1.3 M LiPF 6 EC / EMC / DMC 3:5:2, FEC 10%, LiBF 4 0.2%, 0.5% VC, 1% PS Cut-off voltage (V) Formation: 0.005-1.5, Cycle test: 0.005-1.2 C-rate (C) Formation: 0.1-0.1, 0.01 C cut-off (CV) at 0.005 V

[0231] Sample polymer type Polymer thin film average thickness (nm) Discharge capacity (mAh / g) ICE (%) Cycle retention (%) Cycle Example 1 pDVB 10 16 2 9 8 4.92 1.250 Example 2 pDMAMS 10 16 3 0 8 5.12 0.850 Example 3 pPFDA 10 19 6 2 8 6.13 1.850 Example 4 pGMA 10 15 9 6 8 1.21 9.550 Example 5 pDVB 11 6 1 8 8 5.22 2.950 Example 6 pDVB 5 0 12 0 4 7 4.67 74 4 Comparative Example 1--17 24 8 6 9.750

[0232] As confirmed from Table 4 and Figure 5 above, Examples 1 to 5 showed a reversible capacity of 1500 mAh / g or more, and it was confirmed that ICE and cycle maintenance rate were excellent.

[0233] In addition, in the case of Example 6, it was confirmed that the reversible capacity was lower and the cycle retention rate was also lowered as the average thickness of the polymer thin film was relatively thicker compared to Examples 1 to 5.

[0234] In addition, in the case of Comparative Example 1, it was confirmed that the cycle maintenance rate was significantly reduced as the polymer thin film was not formed.

[0235]

[0236] 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.

[0237]

[0238] [Explanation of symbols]

[0239] 10: Carbon / silicon-polymer composite 11: Porous carbon support

[0240] 12: Silicon 13: Polymer thin film

[0241] 100: Chamber 200: Mounting part

[0242] 300: Inlet 400: Outlet

[0243] 500: Heating unit 1000: Reactor

Claims

1. A carbon-silicon composite comprising a porous carbon support and silicon arranged on the surface and inside the pores of the porous carbon support; and A carbon / silicon-polymer composite comprising a polymer thin film disposed on the surface of the porous carbon support, inside the pores, and on the surface of the silicon.

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

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

4. In paragraph 1, The above polymer film is a carbon / silicon-polymer composite, which accounts for 1 to 30 wt% of the total weight of the carbon / silicon-polymer composite.

5. In paragraph 1, The above polymer thin film is a carbon / silicon-polymer composite having a thickness of 1 to 450 nm. 6.(1) A step of manufacturing a carbon-silicon composite by forming silicon on the surface and inside the pores of a porous carbon support; (2) A method for producing a carbon / silicon-polymer composite, comprising: a step of producing a carbon / silicon-polymer composite by forming a polymer thin film on the surface of the porous carbon support, inside the pores, and on the surface of the silicon of the carbon-silicon composite through an initiator-based chemical vapor deposition (iCVD).

7. In paragraph 6, Step (2) above, (2-1) Step of supplying a carbon-silicon composite into a reactor; (2-2) a step of supplying a monomer and an initiator to the reactor that supplies the carbon-silicon composite; and (2-3) A method for producing a carbon / silicon-polymer composite, comprising: a step of activating the initiator to polymerize the monomer, 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.

8. In paragraph 7, A method for producing a carbon / silicon-polymer composite, wherein 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.

9. In paragraph 7, The above initiator is activated through a predetermined heat treatment, A method for manufacturing a carbon / silicon-polymer composite, wherein the above heat treatment is performed at a temperature of 135 to 350°C.

10. In paragraph 7, The above steps (2-3) are a method for manufacturing a carbon / silicon-polymer composite, which is performed in a vacuum state at a pressure of 50 to 1,000 mTorr for 10 minutes to 6 hours.

11. A carbon / silicon-polymer composite according to any one of claims 1 to 5; and A cathode material comprising a carbon-based cathode material.

12. An all-solid-state battery comprising a SEI (Solid Electrolyte Interphase) film comprising a carbon / silicon-polymer composite according to any one of claims 1 to 5.

13. A lithium ion battery comprising a negative electrode material according to Article 11.

Images