Secondary battery electrode material and method for manufacturing same

Abstract

The present invention relates to a secondary battery electrode material including petroleum pitch and a method for manufacturing same. The secondary battery electrode material is manufactured by forming a coating layer including petroleum pitch on the surface of an electrode active material and then introducing an additional coating layer or performing an additional process, thereby significantly improving the performance of a secondary battery to which the secondary battery electrode material is applied.

Description

Secondary battery electrode material and manufacturing method thereof

[0001] The present invention relates to a secondary battery electrode material including petroleum pitch and a method for manufacturing the same.

[0002]

[0003] Due to the rapid increase in fossil fuel use, the demand for alternative or clean energy is increasing, and as part of this, the most actively researched field is power generation and storage using electrochemical reactions.

[0004] Secondary batteries are a prime example of electrochemical devices that utilize this electrochemical energy, and their applications are expanding. With the recent technological development and increasing demand for portable devices such as laptops, mobile phones, and cameras, the demand for secondary batteries as an energy source has rapidly increased. Among these secondary batteries, lithium secondary batteries, which boast high energy density and high capacity, have been extensively studied and are now commercialized and widely used.

[0005] In general, secondary batteries are composed of a positive electrode, a negative electrode, an electrolyte, and a separator. The positive electrode material of a lithium secondary battery includes a metal oxide such as LiCoO2, Li(NiCoMn)O2, Li(NiCoAl)O2, LiFePO4, LiMnO2, LiMn2O4, or LiCrO2, and the negative electrode material includes a metal lithium, a carbon-based material such as graphite or activated carbon, or a material such as silicon oxide (SiOx). Among the above negative electrode materials, metal lithium was mainly used in the early days, but as the charge and discharge cycle progresses, lithium atoms grow on the surface of the metal lithium, damaging the separator and destroying the battery. Therefore, carbon-based materials are mainly used recently. However, carbon-based materials have a disadvantage of low capacity, with a theoretical capacity of only about 400 mAh / g, and various studies are being conducted to replace the carbon-based materials using high-capacity materials such as silicon (Si), which has a high theoretical capacity (4,200 mAh / g) as a negative electrode material.

[0006] Meanwhile, when using negative electrode materials such as silicon, a technology is being applied to coat the surface of the negative electrode with pitch, which acts as a conductive material and binder, to prevent volume changes. However, the performance of secondary batteries remains inconsistent depending on the pitch used.

[0007]

[0008] The present invention has been devised to overcome the above-described problems, and provides a secondary battery electrode material and a method for manufacturing the same, which can significantly improve the performance of a secondary battery to which the same is applied, by forming a coating layer containing petroleum pitch on the surface of an electrode active material, and then introducing an additional coating layer or performing an additional process to manufacture the secondary battery electrode material.

[0009]

[0010] To solve the above-described problem, the secondary battery electrode material of the present invention may include an electrode active material including silicon (Si), a first coating layer coated on the surface of the electrode active material, and a second coating layer coated on the surface of the second coating layer.

[0011] As a preferred embodiment of the present invention, the first coating layer may include carbonized petroleum pitch.

[0012] As a preferred embodiment of the present invention, the carbonized petroleum pitch may be carbonized at a temperature of 500 to 900°C for 60 to 180 minutes.

[0013] As a preferred embodiment of the present invention, the electrode active material includes a porous carbon support, and silicon can be disposed on the surface and inside the pores of the porous carbon support.

[0014] As a preferred embodiment of the present invention, the electrode active material may include a nonporous carbon support including at least one of hard carbon and soft carbon.

[0015] As a preferred embodiment of the present invention, the electrode active material may be a porous carbon support having an average particle size of 5 to 20 μm.

[0016] As a preferred embodiment of the present invention, the first coating layer may have a thickness of 10 to 400 nm.

[0017] As a preferred embodiment of the present invention, the second coating layer may include carbonized petroleum pitch or carbon.

[0018] As a preferred embodiment of the present invention, the second coating layer may have a thickness of 10 to 400 nm.

[0019] Furthermore, the secondary battery electrode material of the present invention includes an electrode active material including silicon (Si) and a coating layer coated on the surface of the electrode active material, and the coating layer includes carbonized petroleum pitch and may have a thickness of 10 to 95 nm.

[0020] As a preferred embodiment of the present invention, the secondary battery may be a lead (Pd) battery, a nickel-cadmium (NiCd) battery, a nickel-metal (Ni-metal) hydrogen battery, a lithium ion (Li-ion) battery, a solid-state battery, a soft carbon battery, a hard carbon battery, or a lithium ion polymer (Li-ion polymer) battery.

[0021] As a preferred embodiment of the present invention, the electrode active material may be a negative electrode active material.

[0022] As a preferred embodiment of the present invention, the electrode active material may be a spherical activated carbon powder having silicon (Si) coated on the surface.

[0023] As a preferred embodiment of the present invention, the spherical activated carbon may contain 10 to 60 wt% of silicon based on the total wt%.

[0024] As a preferred embodiment of the present invention, the secondary battery electrode material may be a secondary battery negative electrode material.

[0025] Furthermore, the method for manufacturing a secondary battery electrode material of the present invention may include a first step of forming a first coating layer on the surface of an electrode active material by coating petroleum pitch on the surface of the electrode active material, a second step of carbonizing the electrode active material having the first coating layer formed on the surface, a third step of forming a second coating layer on the surface of the carbonized first coating layer by coating petroleum pitch on the surface of the carbonized first coating layer, and a fourth step of carbonizing the negative electrode active material having the first coating layer and the second coating layer sequentially formed on the surface, thereby manufacturing a secondary battery negative electrode material.

[0026] Meanwhile, the method for manufacturing a secondary battery electrode material of the present invention may include a first step of forming a first coating layer on the surface of an electrode active material by coating petroleum pitch on the surface of the electrode active material, a second step of carbonizing the electrode active material on the surface of which the first coating layer has been formed, and a third step of forming a second coating layer made of carbon on the surface of the carbonized first coating layer, thereby manufacturing a secondary battery negative electrode material.

[0027] Furthermore, the method for manufacturing a secondary battery electrode material of the present invention may include a first step of forming a coating layer on the surface of an electrode active material by coating petroleum pitch on the surface of the electrode active material, and a second step of carbonizing the electrode active material on the surface of which the coating layer has been formed, and then performing a CIP (Cold Isostatic Pressing) method to manufacture a secondary battery negative electrode material.

[0028] Meanwhile, the method for manufacturing a secondary battery electrode material of the present invention may include a first step of forming a first coating layer on the surface of an electrode active material by coating petroleum pitch on the surface of the electrode active material and then performing a CIP (Cold Isostatic Pressing) method, a second step of carbonizing the electrode active material having the first coating layer formed on the surface, a third step of forming a second coating layer on the surface of the carbonized first coating layer by coating petroleum pitch on the surface of the carbonized first coating layer, and a fourth step of carbonizing the negative electrode active material having the first coating layer and the second coating layer sequentially formed on the surface, thereby manufacturing a secondary battery negative electrode material.

[0029] As a preferred embodiment of the present invention, the first step coating can be performed by dry coating using the mechano-fusion method.

[0030] As a preferred embodiment of the present invention, the second stage carbonization can be performed at a temperature of 500 to 900°C for 60 to 180 minutes.

[0031] As a preferred embodiment of the present invention, the fourth stage carbonization can be performed at a temperature of 500 to 900°C for 60 to 180 minutes.

[0032] As a preferred embodiment of the present invention, the third step may form a second coating layer made of carbon on the surface of the carbonized first coating layer using a CVD (Chemical Vapor Deposition) method.

[0033]

[0034] The secondary battery electrode material of the present invention and its manufacturing method can significantly improve the performance of a secondary battery to which the secondary battery electrode material is applied by forming a coating layer containing petroleum pitch on the surface of an electrode active material and then introducing an additional coating layer or performing an additional process to manufacture the secondary battery electrode material.

[0035]

[0036] Hereinafter, the present invention will be described in more detail.

[0037] To prevent volume changes when using existing anode materials like silicon, a technology has been applied to coat the surface of the anode with pitch, which acts as a conductive material and binder. However, the performance of secondary batteries has been inconsistent depending on the pitch used.

[0038] Accordingly, the present invention can significantly improve the performance of a secondary battery using the electrode material by forming a coating layer containing petroleum pitch on the surface of an electrode active material and then introducing an additional coating layer or performing an additional process to manufacture a secondary battery electrode material.

[0039]

[0040] The secondary battery electrode material of the present invention may include an electrode active material including silicon (Si), a first coating layer coated on the surface of the electrode active material, and a second coating layer coated on the surface of the first coating layer. In this case, the first coating layer may include carbonized pitch. In addition, the second coating layer may include carbonized pitch and / or carbon.

[0041] The electrode active material containing silicon (Si) may be a porous carbon support containing silicon (Si), and preferably may be a spherical activated carbon powder having silicon (Si) coated on the surface.

[0042] Additionally, the electrode active material may have an average particle size of 20 μm or less, preferably 5 to 20 μm.

[0043] Meanwhile, when the electrode active material is a porous carbon support containing silicon (Si), the first coating layer is formed on the surface of the porous carbon support containing silicon (Si), and the surface of the porous carbon support containing silicon (Si) includes not only the surface exposed to the outside but also the surface located inside. Specifically, the porous carbon support containing silicon (Si) is a porous material having pores on the outer surface and / or the inner surface. For example, when the first coating layer is formed using petroleum pitch, the petroleum pitch penetrates and coats not only the outer surface of the porous carbon support containing silicon (Si) but also the inner surface of the porous carbon support containing silicon (Si) through the pores, thereby partially or completely blocking the pores of the porous carbon support containing silicon (Si), and can be coated on the outer surface of the porous carbon support containing silicon (Si) with a certain thickness to form the first coating layer.

[0044] Furthermore, the second coating layer is formed on the surface of the first coating layer, and the surface of the first coating layer includes not only the surface exposed to the outside but also the surface located inside. Specifically, the porous carbon support including silicon (Si) having the first coating layer coated on the surface is a porous material having pores on the outer surface and / or the inner surface. For example, when the second coating layer is formed using petroleum pitch and / or carbon, the petroleum pitch and / or carbon penetrate and coat not only the outer surface of the porous carbon support including silicon (Si) having the first coating layer coated on the surface, but also the inner surface of the porous carbon support including silicon (Si) having the first coating layer coated on the surface through the pores, thereby partially or completely blocking the pores of the porous carbon support including silicon (Si) having the first coating layer coated on the surface, and can form a second coating layer by coating the outer surface of the porous carbon support including silicon (Si) having the first coating layer coated on the surface with a certain thickness.

[0045] In addition, the spherical activated carbon powder coated with silicon (Si) on the surface means that silicon is formed on the surface of the spherical activated carbon powder, and the surface of the spherical activated carbon powder includes not only the surface exposed to the outside but also the surface located inside. Specifically, the spherical activated carbon powder is a porous material having pores on the outside and / or the inside. For example, when the surface of the spherical activated carbon powder is coated using silicon, the silicon penetrates and coats not only the outside surface of the spherical activated carbon powder but also the inside surface of the spherical activated carbon powder through the pores, thereby partially or completely blocking the pores of the spherical activated carbon powder and coating the outside surface of the spherical activated carbon powder with a certain thickness.

[0046] Furthermore, the spherical activated carbon may contain silicon in an amount of 10 wt% or more, preferably 10 to 60 wt%, based on the total weight.

[0047]

[0048] Meanwhile, the electrode active material may include a porous carbon support containing silicon (Si), and the silicon may be disposed on the surface and inside the pores of the porous carbon support. Specifically, the porous carbon support containing silicon (Si) means that silicon is formed on the surface of an activated carbon porous carbon support, and the surface of the porous carbon support includes not only the surface exposed to the outside but also the surface located inside. Specifically, the porous carbon support is a porous material having pores on the outer surface and / or the inner surface, and for example, when coating the surface of the porous carbon support using silicon, the silicon penetrates and coats not only the outer surface of the porous carbon support but also the inner surface of the porous carbon support through the pores, thereby partially or completely blocking the pores of the porous carbon support, and may be coated with a certain thickness on the outer surface of the porous carbon support.

[0049] In addition, when the electrode active material is a porous carbon support containing silicon (Si), the coating layer is formed on the surface of the porous carbon support containing silicon (Si), and the surface of the porous carbon powder containing silicon (Si) includes not only the surface exposed to the outside but also the surface located inside. Specifically, the porous carbon support containing silicon (Si) is a porous material having pores on the outer surface and / or the inner surface. As an example, when forming a coating layer using petroleum pitch, the petroleum pitch penetrates and coats not only the outer surface of the porous carbon support containing silicon (Si) but also the inner surface of the porous carbon support containing silicon (Si) through the pores, thereby not only blocking some or all of the pores of the porous carbon support containing silicon (Si), but also coating the outer surface of the porous carbon support containing silicon (Si) with a certain thickness to form a coating layer.

[0050] Additionally, the electrode active material may include a nonporous carbon support including at least one of hard carbon and soft carbon.

[0051] Additionally, the electrode active material may most preferably be a carbon-silicon composite.

[0052] A carbon-silicon composite comprises a carbon support including a surface portion and a core portion, and silicon (Si) disposed including a surface of the carbon support.

[0053] In this specification, the core of the carbon support may mean an area within a distance of 1 / 2 the radius of the support from the center of the support, and the surface may mean the remaining area of ​​the support excluding the core.

[0054] The porous 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.

[0055] When the carbon support is a porous carbon support, the porous carbon support can be manufactured by a method including (1) a step of synthesizing pitch by thermal decomposition and condensation polymerization of a petroleum-based raw material, (2) 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, (3) a step of stabilizing the pellet-like pitch or the powder-like pitch, (4) a step of carbonizing the stabilized pitch to obtain a carbonized body, and (5) a step of activating the carbonized body to obtain a porous carbon support.

[0056] Step (1) of the method for manufacturing a porous carbon support according to the present invention may be a step of synthesizing pitch by thermal decomposition and polycondensation of petroleum-based raw materials.

[0057] 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.

[0058] 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.

[0059] 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 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.

[0060] 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 (5) 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 large amount of relatively high molecular weight components, making it difficult to manufacture a carbon support having mesopores.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] In a specific embodiment of the present invention, the pitch synthesized in step (1) 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.

[0067] In a specific embodiment of the present invention, the yield of the pitch synthesized in step (1) may be 10 to 50 wt%. In another specific embodiment of the present invention, the yield of the pitch may be 10 to 40 wt%. In yet another specific embodiment of the present invention, the yield of the pitch may be 20 to 30 wt%.

[0068] In a process for producing a porous carbon support from a petroleum-based raw material according to one embodiment of the present invention, a step of pretreating the petroleum-based raw material may be performed prior to step (1) above. By removing low-boiling-point components contained in the petroleum-based raw material through the pretreatment step, a pitch having a higher softening point can be produced.

[0069] 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 (1), 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.

[0070] In a specific embodiment of the present invention, the pretreatment step may be performed for a time equal to or shorter than the time for thermal decomposition and polycondensation of the petroleum-based raw material in step (1), 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.

[0071] In addition, in the above step (2), the pitch can be solidified and pelletized to obtain a pellet-like pitch, or the pitch can be solidified, pelletized, and pulverized to obtain a powder-like pitch.

[0072] First, in the case of the pellet-shaped pitch, the liquid pitch obtained in step (1) is solidified, for example, by extrusion and cooling, and then 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.

[0073] The pitch pellets (pellet-shaped pitch) obtained in step (2) have an average particle size of 1 to 30 mm, preferably 5 to 25 mm. When the average particle size of the pitch pellets (pellet-shaped pitch) is within this range, a porous carbon support can be manufactured through stabilization, carbonization, and activation described below without separately pulverizing the pitch pellets (pellet-shaped pitch).

[0074] 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, classification can be performed by dry classification, wet classification, or classification using a sieve. Through crushing or pulverization and classification, a powdered pitch having a diameter of 50 to 500 μm can be obtained.

[0075] And, in step (3), a step of stabilizing the pellet-shaped pitch or powder-shaped pitch can be performed. Specifically, step (3) may be a step of stabilizing the structure of the pitch by first oxidizing the pellet-shaped pitch or powder-shaped pitch.

[0076] 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 350°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.

[0077] 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.

[0078] 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 or oxygen, 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.

[0079] 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.

[0080] And, in step (4), 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.

[0081] 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 of the pitch may be performed under a nitrogen or argon atmosphere, but is not particularly limited thereto.

[0082] In a specific embodiment of the present invention, the carbonization may be performed at a temperature of 700°C to 1,000°C, preferably 800°C to 1,000°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.

[0083] 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.

[0084] 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.

[0085] And, in step (5), a porous carbon support can be obtained by activating the carbonized body (carbonized pitch). By activating the carbonized body (carbonized pitch), pores are formed in the pitch, thereby obtaining a porous carbon support.

[0086] In a specific embodiment of the present invention, the activation of the carbonized body may be performed under an oxidizing gas atmosphere. In a preferred embodiment of the present invention, the activation of the carbonized body may be performed under a steam atmosphere, but is not particularly limited thereto.

[0087] In a specific example of the present invention, the activation of the carbonized body can be performed at a temperature of 700°C to 1,000°C or 800°C to 1,000°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.

[0088] 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.

[0089] In a specific example 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.

[0090] 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.

[0091] In a specific embodiment of the present invention, the stabilization, carbonization, and activation of steps (3) to (5) above can each be performed in a heating furnace using microwaves. In a preferred specific embodiment of the present invention, the stabilization, carbonization, and activation of steps (3) to (5) above can all be performed in a heating furnace using microwaves. A heating furnace using microwaves 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.

[0092] In a specific embodiment of the present invention, the stabilization, carbonization, and activation of steps (3) to (5) above can be performed continuously in a single device. In a preferred embodiment of the present invention, the stabilization, carbonization, and activation of steps (3) to (5) above can be performed continuously in a single rotary kiln, but this device is not particularly limited. Since the stabilization, carbonization, and activation are performed continuously in a single device, process optimization can be easily achieved.

[0093] In a specific embodiment of the present invention, the porous carbon support (or porous carbon support powder) obtained in step (5) may be further pulverized or ground and classified. Through pulverization or grounding, the porous carbon support powder can be further finely divided, and through classification, the particle size distribution of the porous carbon support can be made uniform. Here, classification may be dry classification, wet classification, or classification using a sieve. Through pulverization or grounding and classification, a powdered porous carbon support having a diameter of 1 to 20 μm can be obtained.

[0094] The porous carbon support manufactured by performing the above steps (1) to (5) includes mesopores having a diameter of 2 nm to 50 nm, and the ratio of the volume of the mesopores of the surface layer to the volume of the entire mesopores may be 0.5 or more, preferably 0.5 to 0.76. When the ratio of the mesopores of the surface layer to the total mesopores of the porous carbon support is 0.5 or more, the mesopores formed in the surface layer may act as passages through which pores may be formed deep into the porous carbon support, so that silicon may be deposited into the interior of the support. In addition, the volume of the total mesopores of the porous carbon support may refer to the volume of the total mesopores arranged in the interior of the porous carbon support, and the volume of the mesopores of the surface layer may refer to the volume of the total mesopores arranged in the surface layer of the porous carbon support. In addition, the volume of the mesopores of the surface layer may mean the volume of the area corresponding to the surface layer with respect to the entire mesopores arranged in the porous carbon support.

[0095] At this time, if the ratio of the surface mesopores to the entire mesopores of the carbon-silicon composite particles is outside the above range, the charge / discharge capacity may decrease and the cycle characteristics may deteriorate.

[0096] In one example of the present invention, the porous carbon support of the carbon-silicon composite according to the present invention may have a ratio of the volume of mesopores to the total pore volume of 0.1 or more. The pores of the porous carbon support can be classified into micropores with a diameter of less than 2 nm, mesopores with a diameter of 2 nm to 50 nm, and macropores with a diameter of more than 50 nm, depending on their size. Such porous supports have been studied in the direction of increasing the ratio of micropores to increase the specific surface area or increasing the ratio of macropores to increase the amount of material supported inside the pores. However, when there are many micropores, there is a problem that silicon (Si) is difficult to deposit inside the pores, resulting in a decrease in electrical capacity. In addition, when there are many macropores, silicon agglomeration occurs, which can generate stress during repeated charge / discharge processes, which can mechanically damage the negative electrode material.

[0097] On the other hand, in the case of mesopores, silicon can be sufficiently deposited deep within the pores during deposition. The carbon-silicon composite particles according to the present invention can deposit a sufficient amount of silicon within the pores of the porous support by including mesopores within a predetermined range.

[0098] In addition, the porous carbon support may have a higher porosity in the surface layer than in the deep layer, and thus may be more advantageous in achieving the purpose of the present invention.

[0099] The ratio of the volume of the mesopores to the volume of the entire pores of the porous carbon support may be, but is not limited to, 0.10 or more, 0.12 or more, 0.14 or more, or 0.15 or more. The upper limit of the ratio of the volume of the mesopores to the volume of the entire pores of the porous carbon support is not particularly limited, but may be, for example, 0.7 or less. When the ratio of the volume of the mesopores to the volume of the entire pores of the porous carbon support satisfies the above range, the porous carbon support has excellent electrical properties while preventing excessive aggregation of silicon, thereby preventing damage due to volume expansion of silicon.

[0100] In one embodiment of the present invention, the tap density of the porous carbon support may be 0.7 g / ml or less. The tap density of the porous carbon support may be a value measured using PT-TD200 (Pharma Test). Specifically, 40 ml of the porous carbon support is loaded into a cylinder, tapped 1,000 times, and the primary volume is observed. After the observation, the process of performing another 1,000 taps and observing the volume is repeated three times until there is no difference from the previous volume, and then the tap density can be calculated using the final volume. The tap density of the porous carbon support may be 0.70 g / ml or less, 0.65 g / ml or less, or 0.60 g / ml or less, and may be 0.05 g / ml or more, 0.10 g / ml or more, 0.15 g / ml or more, 0.20 g / ml or more, or 0.22 g / ml or more, but is not limited thereto. If the tap density of the porous carbon support is too low, process control may be difficult during silane gas deposition, resulting in a decrease in yield. In addition, if the tap density of the porous carbon support is too high, uniform coating may be difficult during silane gas deposition.

[0101] In one example of the present invention, the BET (Brunauer-Emmett-Teller) specific surface area of ​​the porous carbon support according to the present invention is 200 m 2 / g ~ 3,000 m 2 / g range. The BET specific surface area of ​​the porous carbon support may be a value measured using ASAP 2420 (Micromeritics instrument (USA)). Specifically, analysis was performed after vacuum drying at 300°C for 5 hours, and the N2 / 77K Isotherm adsorption results can be calculated using the BET equation and the BJH equation according to ISO9277. The BET specific surface area of ​​the porous carbon support may be 200 ㎡ / g or more, 400 ㎡ / g or more, or 500 ㎡ / g or more, and may be 3,000 ㎡ / g or less, 2,800 ㎡ / g or less, 2,600 ㎡ / g or less, 2,000 ㎡ / g or less, or 1,900 ㎡ / g or less, but is not limited thereto. If the BET surface area of ​​the porous carbon support is excessively low, the proportion of macropores may increase, which may lower the mechanical strength of the negative electrode material and result in a lack of effective pores. In addition, if the BET surface area of ​​the porous carbon support is excessively high, the proportion of micropores may increase, and silicon may not be sufficiently deposited deep into the porous carbon support.

[0102] The diameter of the above porous carbon support may be 20 μm or less. The diameter is D 50It may refer to the diameter, and may be a value measured using MICROTRAC S3500 equipment. Specifically, it may refer to an average value obtained by dispersing a porous carbon support in ethanol and then performing particle size analysis three times. The diameter of the porous carbon support may be 20 ㎛ or less, 18 ㎛ or less, 16 ㎛ or less, 14 ㎛ or less, 12 ㎛ or less, or 10 ㎛ or less, and may be 1 ㎛ or more, 2 ㎛ or more, 3 ㎛ or more, 4 ㎛ or more, or 4.5 ㎛ or more, but is not limited thereto. If the diameter of the porous carbon support is too small, when performing coating, silicon may be quickly filled inside and then additional coating may be performed on the surface, so that the surface coating layer may be formed thickly. In this case, deterioration may be accelerated during charge and discharge, and agglomeration of materials with small particle sizes may occur when manufacturing an electrode, and deterioration of the agglomerated portion may be significant. In addition, if the diameter of the porous carbon support is too large, it may be difficult for silane gas to diffuse into the interior of the porous carbon support, making it difficult to form a uniform silicon coating layer inside the support. In addition, if the diameter of the porous carbon support is too large, it may be difficult to uniformly coat the slurry on the current collector during electrode manufacturing, which may result in a decrease in capacity uniformity.

[0103] In one example, the porous carbon support of the carbon-silicon composite according to the present invention may include macropores having a diameter exceeding 50 nm. At this time, the ratio of the volume of the macropores to the total pore volume of the porous carbon support may be 0.4 or less. The ratio of the volume of the macropores to the total pore volume of the porous carbon support may be 0.40 or less, 0.35 or less, 0.30 or less, 0.25 or less, 0.20 or less, or 0.15 or less, but is not limited thereto. The lower limit of the ratio of the volume of the macropores to the total pore volume of the porous carbon support is not particularly limited, but may be, for example, 0 or more or greater than 0. If the ratio of the macropores of the porous carbon support of the carbon-silicon composite is too high, the mechanical strength of the negative electrode material manufactured from the carbon-silicon composite may be reduced. In addition, local agglomeration of silicon occurs inside the negative electrode material, which can cause stress due to volume expansion during repeated charge and discharge processes, thereby causing damage to the negative electrode material.

[0104] In addition, when the carbon support is hard carbon, the hard carbon can be manufactured by a method including the steps of (1') synthesizing pitch by thermal decomposition and condensation polymerization of petroleum-based raw materials, (2') solidifying and pelletizing the pitch to obtain pellet-like pitch, or solidifying, pelletizing, and pulverizing the pitch to obtain powder-like pitch, (3') stabilizing the pellet-like pitch or powder-like pitch, and (4') carbonizing the stabilized pitch to obtain hard carbon.

[0105] At this time, since the description of the above steps (1') to (4') may be the same as the description of the above steps (1) to (4), a detailed description will be omitted.

[0106] 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.

[0107] In addition, when the carbon support is soft carbon, the soft carbon can be manufactured by a method including the steps of (1") synthesizing pitch by thermal decomposition and condensation polymerization of petroleum-based raw materials, (2") solidifying and pelletizing the pitch to obtain pellet-like pitch, or solidifying, pelletizing, and pulverizing the pitch to obtain powder-like pitch, (3") stabilizing the pellet-like pitch or powder-like pitch, and (4") carbonizing the stabilized pitch to obtain soft carbon.

[0108] At this time, the description of the above steps (1") and (2") may be the same as the description of the above steps (1) and (2), so a detailed description will be omitted.

[0109] The above step (3") and the step (4") described below may be performed as a series of steps in a rotary kiln, as in the above-described steps (3) and (4), or may be performed as a series of steps by placing the material in a crucible and placing it in an oven. Preferably, it may be advantageous to achieve the purpose of the present invention to perform the series of steps by placing the material in a crucible and placing it in an oven.

[0110] Meanwhile, since the description of the contents other than the above step (3") may be the same as the description of the above step (3), a detailed description will be omitted.

[0111] In addition, the above step (4") 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.

[0112] In a specific embodiment of the present invention, the carbonization in step (4") may be performed under an inert gas atmosphere. In a preferred specific embodiment of the present invention, the carbonization in step (4") may be performed under a nitrogen or argon atmosphere, but is not particularly limited thereto.

[0113] In a specific example of the present invention, the carbonization in step (4") 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 (4") 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.

[0114] In a specific example of the present invention, the carbonization in step (4") can 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.

[0115] In a specific example of the present invention, the carbonization in step (4") can be performed for 0.5 to 5 hours, preferably 1 to 3 hours. When the carbonization in step (4") is performed for this period of time, the stabilized pitch can be sufficiently carbonized.

[0116] Meanwhile, since the description of the contents other than the above step (4") may be the same as the description of the above step (4), a detailed description will be omitted.

[0117] 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.

[0118]

[0119] Pitch, which may be included in the first coating layer and / or the second coating layer, is a solid organic material at room temperature or a residue resulting from the thermal decomposition of tar distillation, and is composed of a complex mixture of numerous highly aromatic hydrocarbons and heterocyclic compounds. Pitch is not a substance with a constant melting point, but rather has a wide softening range, with a softening temperature ranging from approximately 320 K to 570 K, depending on the molecular weight and component composition.

[0120] The pitch of the present invention may include at least one selected from petroleum pitch, coal tar pitch, and mesogenic pitch, and preferably may include petroleum pitch.

[0121] In addition, the secondary battery of the present invention may be a lead (Pd) battery, a nickel-cadmium (NiCd) battery, a nickel-metal (Ni-metal) hydrogen battery, a lithium ion (Li-ion) battery, a solid-state battery, a soft carbon battery, a hard carbon battery, or a lithium ion polymer (Li-ion) battery, and preferably a lithium ion (Li-ion) battery.

[0122] Additionally, the electrode active material of the present invention may be a negative electrode active material, and the negative electrode active material may include silicon (Si).

[0123]

[0124] Meanwhile, the first coating layer can be formed by coating petroleum pitch on the surface of an electrode active material including silicon and then carbonizing it.

[0125] More specifically, the carbonized petroleum pitch may be carbonized at a temperature of 500 to 900°C, preferably 600 to 800°C, and even more preferably 650 to 750°C for 60 to 180 minutes, and preferably 90 to 150 minutes. At this time, if the carbonization temperature is less than 500°C, there may be a problem of incomplete carbonization, and if it exceeds 900°C, there may be a problem of excessive reaction with silicon. In addition, if the carbonization time is less than 60 minutes, there may be a problem of incomplete carbonization, and if it exceeds 180 minutes, there may be a problem of excessive reaction with silicon.

[0126] In addition, the first coating layer may have a thickness of 10 to 400 nm, preferably 20 to 300 nm, more preferably 30 to 200 nm, and even more preferably 30 to 150 nm. If the thickness is less than 10 nm, the effect of suppressing the increase in expansion rate may be insignificant, and if it exceeds 400 nm, it is advantageous in terms of low expansion rate and suppression of side reaction layer formation, but the effect of increasing the electrical efficiency of the secondary battery may be reduced.

[0127] Furthermore, the second coating layer may be formed by coating petroleum pitch on the surface of the electrode active material including silicon coated with the first coating layer and then carbonizing it, or may be formed on the surface of the electrode active material including silicon coated with the first coating layer using a CVD (Chemical Vapor Deposition) method.

[0128] In addition, the second coating layer may have a thickness of 10 to 400 nm, preferably 20 to 300 nm, more preferably 20 to 200 nm, and even more preferably 20 to 150 nm. If the thickness is less than 10 nm, the effect of suppressing the increase in expansion rate may be insignificant, and if it exceeds 400 nm, it is advantageous in terms of low expansion rate and suppression of side reaction layer formation, but the effect of increasing the electrical efficiency of the secondary battery may be reduced.

[0129] Additionally, the secondary battery electrode material of the present invention may be a secondary battery negative electrode material.

[0130]

[0131] Meanwhile, another secondary battery electrode material of the present invention includes an electrode active material including silicon (Si) and a coating layer coated on the surface of the electrode active material, and the coating layer includes carbonized petroleum pitch and may have a thickness of 10 to 95 nm. Unlike the secondary battery electrode material of the present invention including the first and second coating layers described above, another secondary battery electrode material of the present invention has a single coating layer and may have a thinner thickness through the CIP (Cold Isostatic Pressing) method.

[0132]

[0133] Furthermore, the method for manufacturing a secondary battery electrode material of the present invention includes steps 1 to 4.

[0134] First, in the first step of the method for manufacturing a secondary battery electrode material of the present invention, a first coating layer can be formed on the surface of the electrode active material by coating the surface of the electrode active material with petroleum pitch. At this time, the electrode active material and / or the petroleum pitch are each as described above.

[0135] Additionally, the first stage coating can be performed by dry coating using the mechano-fusion method.

[0136] Specifically, dry coating can be performed at a speed of 500 to 5,000 rpm, preferably 900 to 4,500 rpm, for 5 to 30 minutes, preferably 10 to 20 minutes. If the speed is less than 500 rpm, there may be a problem of coating detachment, and if it exceeds 5,000 rpm, there may be a problem of particle damage. In addition, if the time is less than 10 minutes, there may be a problem of incomplete coating, and if it exceeds 30 minutes, there may be a problem of particle damage.

[0137] Next, the second step of the method for manufacturing a secondary battery electrode material of the present invention can carbonize an electrode active material having a first coating layer formed on the surface.

[0138] At this time, carbonization can be performed at a temperature of 500 to 900°C, preferably 600 to 800°C, more preferably 650 to 750°C, for 60 to 180 minutes, preferably 90 to 150 minutes.

[0139] Additionally, the carbonized first coating layer may have a thickness of 10 to 400 nm, preferably 30 to 300 nm, more preferably 50 to 200 nm, and even more preferably 80 to 150 nm.

[0140] Next, in the third step of the method for manufacturing a secondary battery electrode material of the present invention, a second coating layer can be formed on the surface of the carbonized first coating layer by coating petroleum pitch on the surface of the carbonized first coating layer. In this case, the petroleum pitch is as described above.

[0141] Additionally, the third-stage coating can be performed by dry coating using the mechano-fusion method.

[0142] Specifically, dry coating can be performed at a speed of 500 to 5,000 rpm, preferably 900 to 4,500 rpm, for 5 to 30 minutes, preferably 10 to 20 minutes. If the speed is less than 500 rpm, there may be a problem of coating detachment, and if it exceeds 5,000 rpm, there may be a problem of particle damage. In addition, if the time is less than 5 minutes, there may be a problem of incomplete coating, and if it exceeds 30 minutes, there may be a problem of particle damage.

[0143] Next, in the fourth step of the method for manufacturing a secondary battery electrode material of the present invention, a secondary battery negative electrode material can be manufactured by carbonizing a negative electrode active material on the surface of which a first coating layer and a second coating layer are sequentially formed.

[0144] At this time, carbonization can be performed at a temperature of 500 to 900°C, preferably 600 to 800°C, more preferably 650 to 750°C, for 60 to 180 minutes, preferably 90 to 150 minutes.

[0145] Additionally, the carbonized second coating layer may have a thickness of 10 to 400 nm, preferably 30 to 300 nm, more preferably 50 to 200 nm, and even more preferably 80 to 150 nm.

[0146] In addition, the first coating layer and the second coating layer manufactured by the method for manufacturing a secondary battery electrode material of the present invention may have a thickness ratio of 1:0.8 to 1.2, preferably a thickness ratio of 1:0.9 to 1.1, and by satisfying such a thickness ratio, a secondary battery electrode material having the desired performance can be manufactured.

[0147]

[0148] Meanwhile, another method for manufacturing a secondary battery electrode material of the present invention includes steps 1 to 3.

[0149] First, in the first step of another method for manufacturing a secondary battery electrode material of the present invention, a first coating layer can be formed on the surface of the electrode active material by coating the surface of the electrode active material with petroleum pitch. In this case, the electrode active material and / or the petroleum pitch are as described above, respectively.

[0150] Additionally, the first stage coating can be performed by dry coating using the mechano-fusion method.

[0151] Specifically, dry coating can be performed at a speed of 500 to 5,000 rpm, preferably 900 to 4,500 rpm, for 5 to 30 minutes, preferably 10 to 20 minutes. If the speed is less than 500 rpm, there may be a problem of coating detachment, and if it exceeds 5,000 rpm, there may be a problem of particle damage. In addition, if the time is less than 5 minutes, there may be a problem of incomplete coating, and if it exceeds 30 minutes, there may be a problem of particle damage.

[0152] Next, the second step of another method for manufacturing a secondary battery electrode material of the present invention can carbonize an electrode active material having a first coating layer formed on the surface.

[0153] At this time, carbonization can be performed at a temperature of 500 to 900°C, preferably 600 to 800°C, more preferably 650 to 750°C, for 60 to 180 minutes, preferably 90 to 150 minutes.

[0154] Additionally, the carbonized first coating layer may have a thickness of 10 to 400 nm, preferably 30 to 300 nm, more preferably 50 to 200 nm, and even more preferably 80 to 150 nm.

[0155] Next, in the third step of the method for manufacturing another secondary battery electrode material of the present invention, a second coating layer made of carbon can be formed on the surface of the carbonized first coating layer, thereby manufacturing a secondary battery negative electrode material. Specifically, in the third step, a second coating layer made of carbon can be formed on the surface of the carbonized first coating layer using a CVD (Chemical Vapor Deposition) method, and as a precursor for performing the CVD (Chemical Vapor Deposition) method, any precursor used in the art to enable carbon to be coated and / or deposited during coating and / or deposition can be used, and preferably, ethylene can be used.

[0156] Specifically, the CVD method can be performed at a reaction temperature of 375 to 575°C, preferably 400 to 550°C, more preferably 425 to 525°C, and even more preferably 450 to 500°C, an ethylene flow rate of 800 to 1200 sccm, preferably 900 to 1100 sccm, and even more preferably 950 to 1050 sccm, and a reaction time of 10 to 60 minutes, preferably 20 to 50 minutes, and even more preferably 20 to 40 minutes, and by satisfying these conditions, a secondary battery electrode material having the desired performance can be manufactured.

[0157] Additionally, the formed second coating layer may have a thickness of 10 to 400 nm, preferably 10 to 100 nm, more preferably 10 to 50 nm, and even more preferably 15 to 30 nm.

[0158] In addition, the first coating layer and the second coating layer manufactured by another method for manufacturing a secondary battery electrode material of the present invention may have a thickness ratio of 1:0.05 to 0.5, preferably a thickness ratio of 1:0.1 to 0.3, and more preferably a thickness ratio of 1:0.15 to 0.25, and by satisfying such a thickness ratio, a secondary battery electrode material having the desired performance can be manufactured.

[0159]

[0160] Furthermore, another method for manufacturing a secondary battery electrode material of the present invention includes a first step and a second step.

[0161] First, the first step of another method for manufacturing a secondary battery electrode material of the present invention can form a coating layer on the surface of the electrode active material by coating the surface of the electrode active material with petroleum pitch. In this case, the electrode active material and / or the petroleum pitch are as described above, respectively.

[0162] Additionally, the first stage coating can be performed by dry coating using the mechano-fusion method.

[0163] Specifically, dry coating can be performed at a speed of 500 to 5,000 rpm, preferably 900 to 4,500 rpm, for 5 to 30 minutes, preferably 10 to 20 minutes. If the speed is less than 500 rpm, there may be a problem of coating detachment, and if it exceeds 5,000 rpm, there may be a problem of particle damage. In addition, if the time is less than 5 minutes, there may be a problem of incomplete coating, and if it exceeds 30 minutes, there may be a problem of particle damage.

[0164] Next, in the second step of another method for manufacturing a secondary battery electrode material of the present invention, a secondary battery negative electrode material can be manufactured by carbonizing an electrode active material having a coating layer formed on its surface and then performing a CIP (Cold Isostatic Pressing) method. At this time, the carbonization can be performed at a temperature of 500 to 900°C, preferably 600 to 800°C, and more preferably 650 to 750°C for 60 to 240 minutes, and preferably 150 to 210 minutes. In addition, the CIP method can use water as a compressed fluid, and can be performed under conditions of a temperature of 15 to 30°C, preferably 20 to 28°C, more preferably 23 to 27°C, and a pressure of 15,000 to 25,000 psi, preferably 17,000 to 23,000 psi, more preferably 19,000 to 21,000 psi, and by satisfying these conditions, a secondary battery electrode material having the desired performance can be manufactured. In addition, by performing the CIP method, the coating layer manufactured by another method for manufacturing a secondary battery electrode material of the present invention can have a thickness of 10 to 95 nm, preferably a thickness of 20 to 70 nm, more preferably a thickness of 40 to 60 nm, which can have an advantage of having a thinner thickness and better performance than when the coating layer is formed using the mechano-fusion method.

[0165]

[0166] Meanwhile, another method for manufacturing a secondary battery electrode material of the present invention includes steps 1 to 4.

[0167] First, in the first step of another method for manufacturing a secondary battery electrode material of the present invention, petroleum pitch is coated on the surface of an electrode active material, and then a cold isostatic pressing (CIP) method is performed to form a first coating layer on the surface of the electrode active material. At this time, the electrode active material and / or petroleum pitch are each as described above.

[0168] Additionally, the first stage coating can be performed by dry coating using the mechano-fusion method.

[0169] Specifically, dry coating can be performed at a speed of 500 to 5,000 rpm, preferably 900 to 4,500 rpm, for 5 to 30 minutes, preferably 10 to 20 minutes. If the speed is less than 500 rpm, there may be a problem of coating detachment, and if it exceeds 5,000 rpm, there may be a problem of particle damage. In addition, if the time is less than 5 minutes, there may be a problem of incomplete coating, and if it exceeds 30 minutes, there may be a problem of particle damage.

[0170] In addition, the CIP method can use water as a compressed fluid, and can be performed at a temperature of 15 to 30°C, preferably 20 to 28°C, more preferably 23 to 27°C, and a pressure of 15,000 to 25,000 psi, preferably 17,000 to 23,000 psi, more preferably 19,000 to 21,000 psi, and by satisfying these conditions, a secondary battery electrode material having the desired performance can be manufactured.

[0171] Next, the second step of another method for manufacturing a secondary battery electrode material of the present invention can carbonize an electrode active material having a first coating layer formed on the surface.

[0172] At this time, carbonization can be performed at a temperature of 500 to 900°C, preferably 600 to 800°C, more preferably 650 to 750°C, for 60 to 180 minutes, preferably 90 to 150 minutes.

[0173] Additionally, the carbonized first coating layer may have a thickness of 10 to 400 nm, preferably 20 to 300 nm, more preferably 30 to 100 nm, and even more preferably 40 to 70 nm.

[0174] Next, in the third step of another method for manufacturing a secondary battery electrode material of the present invention, a second coating layer can be formed on the surface of the carbonized first coating layer by coating petroleum pitch on the surface of the carbonized first coating layer. In this case, the petroleum pitch is as described above.

[0175] Additionally, the third-stage coating can be performed by dry coating using the mechano-fusion method.

[0176] Specifically, dry coating can be performed at a speed of 500 to 5,000 rpm, preferably 900 to 4,500 rpm, for 5 to 30 minutes, preferably 10 to 20 minutes. If the speed is less than 500 rpm, there may be a problem of coating detachment, and if it exceeds 5,000 rpm, there may be a problem of particle damage. In addition, if the time is less than 5 minutes, there may be a problem of incomplete coating, and if it exceeds 30 minutes, there may be a problem of particle damage.

[0177] Next, in the fourth step of another method for manufacturing a secondary battery electrode material of the present invention, a secondary battery negative electrode material can be manufactured by carbonizing a negative electrode active material on which a first coating layer and a second coating layer are sequentially formed on the surface.

[0178] At this time, carbonization can be performed at a temperature of 500 to 900°C, preferably 600 to 800°C, more preferably 650 to 750°C, for 60 to 180 minutes, preferably 90 to 150 minutes.

[0179] Additionally, the carbonized second coating layer may have a thickness of 10 to 400 nm, preferably 30 to 300 nm, more preferably 50 to 200 nm, and even more preferably 80 to 150 nm.

[0180] In addition, the first coating layer and the second coating layer manufactured by another method for manufacturing a secondary battery electrode material of the present invention may have a thickness ratio of 1:1 to 3, preferably a thickness ratio of 1:1.5 to 2.5, and more preferably a thickness ratio of 1:1.8 to 2.2, and by satisfying such thickness ratios, a secondary battery electrode material having the desired performance can be manufactured.

[0181]

[0182] Hereinafter, the present invention will be described in more detail through examples, but the following examples do not limit the scope of the present invention, and should be interpreted as helping to understand the present invention.

[0183]

[0184] Example 1: Preparation of secondary battery negative electrode material

[0185] (1) Using the mechano-fusion method, petroleum pitch was dry-coated on the surface of the negative electrode active material to form a first coating layer on the surface of the negative electrode active material. At this time, spherical activated carbon powder with silicon (Si) coated on the surface was used as the negative electrode active material, and the coating was performed at a speed of 2700 rpm for 15 minutes.

[0186] (2) The negative active material having a first coating layer formed on the surface was carbonized at a temperature of 700°C for 120 minutes.

[0187] (3) A secondary battery negative electrode material was manufactured by forming a second coating layer made of carbon on the surface of a carbonized first coating layer using a CVD (Chemical Vapor Deposition) method using ethylene as a precursor. Meanwhile, the CVD method was performed at a reaction temperature of 475°C, an ethylene flow rate of 1000 sccm, and a reaction time of 30 minutes, and the first coating layer of the manufactured secondary battery negative electrode material was formed to a thickness of 100 nm, and the second coating layer was formed to a thickness of 20 nm.

[0188]

[0189] Example 2: Manufacturing of secondary battery negative electrode material

[0190] (1) Using the mechano-fusion method, petroleum pitch was dry-coated on the surface of the negative electrode active material to form a first coating layer on the surface of the negative electrode active material. At this time, spherical activated carbon powder with silicon (Si) coated on the surface was used as the negative electrode active material, and the coating was performed at a speed of 2700 rpm for 15 minutes.

[0191] (2) The negative active material having a first coating layer formed on the surface was carbonized at a temperature of 700°C for 120 minutes.

[0192] (3) Using the mechano-fusion method, petroleum pitch was dry-coated on the surface of the carbonized first coating layer to form a second coating layer on the surface of the first coating layer. At this time, the coating was performed at a speed of 2700 rpm for 15 minutes.

[0193] (4) A negative electrode active material having a first coating layer and a second coating layer sequentially formed on the surface was carbonized at a temperature of 700°C for 120 minutes to manufacture a secondary battery negative electrode material. Meanwhile, the first coating layer of the manufactured secondary battery negative electrode material was formed to a thickness of 100 nm, and the second coating layer was formed to a thickness of 100 nm.

[0194]

[0195] Example 3: Preparation of secondary battery negative electrode material

[0196] (1) Using the mechano-fusion method, petroleum pitch was dry-coated on the surface of the negative electrode active material to form a coating layer on the surface of the negative electrode active material. At this time, spherical activated carbon powder with silicon (Si) coated on the surface was used as the negative electrode active material, and the coating was performed at a speed of 2700 rpm for 15 minutes.

[0197] (2) The negative electrode active material having a coating layer formed on the surface was carbonized at a temperature of 700°C for 180 minutes, and then the CIP (Cold Isostatic Pressing) method was performed to manufacture a secondary battery negative electrode material. Meanwhile, the CIP method was performed using water as a compressed fluid, at a temperature of 25°C, and a pressure of 20,000 psi, and the coating layer of the manufactured secondary battery negative electrode material was formed with a thickness of 50 nm.

[0198]

[0199] Example 4: Manufacturing of secondary battery negative electrode material

[0200] (1) Using the mechano-fusion method, petroleum pitch was dry-coated on the surface of the negative electrode active material, and the cold isostatic pressing (CIP) method was performed to form a first coating layer on the surface of the negative electrode active material. At this time, spherical activated carbon powder with silicon (Si) coated on the surface was used as the negative electrode active material, and the coating was performed at a speed of 2700 rpm for 15 minutes. In addition, the CIP method was performed using water as the compressed fluid under the conditions of a temperature of 25°C and a pressure of 20,000 psi.

[0201] (2) The negative active material having a first coating layer formed on the surface was carbonized at a temperature of 700°C for 120 minutes.

[0202] (3) Using the mechano-fusion method, petroleum pitch was dry-coated on the surface of the carbonized first coating layer to form a second coating layer on the surface of the first coating layer. At this time, the coating was performed at a speed of 2700 rpm for 15 minutes.

[0203] (4) A negative electrode active material having a first coating layer and a second coating layer sequentially formed on the surface was carbonized at a temperature of 700°C for 120 minutes to manufacture a secondary battery negative electrode material. Meanwhile, the first coating layer of the manufactured secondary battery negative electrode material was formed to a thickness of 50 nm, and the second coating layer was formed to a thickness of 100 nm.

[0204]

[0205] Comparative Example 1: Manufacturing of secondary battery negative electrode material

[0206] (1) Using the mechano-fusion method, petroleum pitch was dry-coated on the surface of the negative electrode active material to form a coating layer on the surface of the negative electrode active material. At this time, spherical activated carbon powder with silicon (Si) coated on the surface was used as the negative electrode active material, and the coating was performed at a speed of 2700 rpm for 15 minutes.

[0207] (2) A secondary battery negative electrode material was manufactured by carbonizing a negative electrode active material having a coating layer formed on its surface at a temperature of 700°C for 120 minutes. Meanwhile, the coating layer of the manufactured secondary battery negative electrode material was formed to a thickness of 100 nm.

[0208]

[0209] Manufacturing Example 1: Manufacturing of a secondary battery half coin cell

[0210] (1) The secondary battery negative electrode material, conductive material, and binder manufactured in Example 1 were mixed to manufacture a negative electrode material slurry. At this time, the negative electrode material slurry was mixed with 80 wt% of the secondary battery negative electrode material manufactured in Example 1, 10 wt% of the conductive material, and 10 wt% of the binder based on 100 wt% of the total. Super-P, which is a conductive carbon black, was used as the conductive material, and styrene butadiene rubber (SBR) and sodium carboxymethyl cellulose (CMC) were mixed in a weight ratio of 5:5 as the binder.

[0211] (2) Copper foil was prepared, and the negative electrode slurry was uniformly applied to the surface of the prepared copper foil, and dried in an oven at 80°C for 1 hour. After the primary drying, roll pressing was performed, and secondary drying was performed in a vacuum oven at 120°C for 6 hours and 30 minutes to manufacture a negative electrode plate.

[0212] (3) Lithium foil was prepared, and the prepared lithium foil and the negative electrode plate were used as counter electrodes, and a porous polyethylene film was used as a separator, and a secondary battery half coin cell was manufactured by punching to have a diameter of 20 mm and a thickness of 3.2 mm. In addition, the manufactured secondary battery half coin cell was filled with an electrolyte, and a 1.3M LiPF6 solution containing 10 wt% fluoro-ethylene carbonate (FEC), 0.2 wt% lithium tetrafluoroborate (LiBF4), 0.5 wt% vinylene carbonate (VC), and 1 wt% propane sulton (PS) additive was dissolved in a mixed solution, and the mixed solution was a mixture of 30 vol% ethylene carbonate (EC), 50 vol% ethyl methyl carbonate (EMC), and 20 vol% dimethyl carbonate (DMC) with respect to the total 100 vol%.

[0213]

[0214] Manufacturing Example 2: Manufacturing of a secondary battery half coin cell

[0215] A secondary battery half-coil cell was manufactured using the same method as Manufacturing Example 1. However, unlike Manufacturing Example 1, the secondary battery negative electrode material manufactured in Example 2 was used instead of the secondary battery negative electrode material manufactured in Example 1, and a secondary battery half-coil cell was finally manufactured.

[0216]

[0217] Manufacturing Example 3: Manufacturing of a secondary battery half coin cell

[0218] A secondary battery half-coil cell was manufactured using the same method as Manufacturing Example 1. However, unlike Manufacturing Example 1, the secondary battery negative electrode material manufactured in Example 3 was used instead of the secondary battery negative electrode material manufactured in Example 1, and a secondary battery half-coil cell was finally manufactured.

[0219]

[0220] Manufacturing Example 4: Manufacturing of a secondary battery half coin cell

[0221] A secondary battery half-coil cell was manufactured using the same method as Manufacturing Example 1. However, unlike Manufacturing Example 1, the secondary battery negative electrode material manufactured in Example 4 was used instead of the secondary battery negative electrode material manufactured in Example 1, and a secondary battery half-coil cell was finally manufactured.

[0222]

[0223] Comparative Manufacturing Example 1: Manufacturing of a Secondary Battery Half Coin Cell

[0224] A secondary battery half-coil cell was manufactured using the same method as Manufacturing Example 1. However, unlike Manufacturing Example 1, the secondary battery negative electrode material manufactured in Comparative Example 1 was used instead of the secondary battery negative electrode material manufactured in Example 1, and a secondary battery half-coil cell was finally manufactured.

[0225]

[0226] Reference Example 1: Manufacturing of a Secondary Battery Half Coin Cell

[0227] A secondary battery half-coil cell was manufactured using the same method as Manufacturing Example 1. However, unlike Manufacturing Example 1, instead of the secondary battery negative electrode material manufactured in Example 1, a spherical activated carbon powder with silicon (Si) coated on the surface was used to manufacture a secondary battery half-coil cell.

[0228]

[0229] Experimental Example 1: Measurement of electric capacity, initial charge-discharge efficiency (ICE), and charge-discharge efficiency after 50 charge-discharge cycles.

[0230] Using a charger / discharger (WBCS3000, Wonatech), the electric capacity (= charge capacity and discharge capacity), initial charge / discharge efficiency (ICE), volume expansion reduction rate after 50 charge / discharge cycles, and retention rate compared to the initial electric capacity after 50 charge / discharge cycles of the secondary battery coin cells manufactured in Manufacturing Examples 1 to 4 and Comparative Manufacturing Example 1 were measured, and the results are shown in Table 1 below. Meanwhile, the volume expansion reduction rate after 50 charge / discharge cycles was calculated using the following equation 1.

[0231] [Relationship 1]

[0232] Volume expansion reduction rate (%) after 50 charge / discharge cycles = (BA) / B × 100%

[0233] In the above relational expression 1, A represents the volume expansion rate of each of the secondary battery coin cells manufactured in Manufacturing Examples 1 to 4 and Comparative Manufacturing Example 1 after 50 cycles of charging and discharging, and B represents the volume expansion rate of the secondary battery half coin cell manufactured in Reference Example 1 after 50 cycles of charging and discharging.

[0234]

[0235]

[0236] As can be seen in Table 1, the secondary battery coin cells manufactured in Manufacturing Examples 1 to 4 not only had superior electric capacity and initial charge / discharge efficiency compared to the secondary battery coin cells manufactured in Comparative Manufacturing Example 1, but also had superior volume expansion reduction rate after 50 charge / discharge cycles and retention rate compared to the initial electric capacity after 50 charge / discharge cycles.

[0237] Specifically, it was confirmed that the secondary battery coin cell manufactured in Manufacturing Example 1 not only had the best electric capacity and initial charge / discharge efficiency, but also had the best volume expansion reduction rate after 50 charge / discharge cycles and the best retention rate compared to the initial electric capacity after 50 charge / discharge cycles.

[0238] Compared to the secondary battery coin cell manufactured in Manufacturing Example 1,

[0239] It was confirmed that the secondary battery coin cell manufactured in Comparative Manufacturing Example 1 had severe volume expansion and a reduced capacity retention rate.

[0240] It was confirmed that the secondary battery coin cell manufactured in Manufacturing Example 2 had a reduced capacity retention rate.

[0241] It was confirmed that the secondary battery coin cell manufactured in Manufacturing Example 3 not only showed increased volume expansion, but also had decreased capacity, initial charge / discharge efficiency, and capacity retention rate.

[0242] It was confirmed that the secondary battery coin cell manufactured in Manufacturing Example 4 had a reduced capacity retention rate.

[0243]

[0244] The above illustrates and describes specific embodiments. However, the invention is not limited to the aforementioned embodiments, and those skilled in the art will readily appreciate that various modifications and implementations can be made without departing from the spirit and scope of the invention as set forth in the claims below.

Claims

1. Electrode active material containing silicon (Si); A first coating layer coated on the surface of the electrode active material; and A second coating layer coated on the surface of the first coating layer; A secondary battery electrode material, wherein the first coating layer comprises carbonized petroleum-based pitch.

2. In paragraph 1, The above carbonized petroleum pitch is a secondary battery electrode material carbonized at a temperature of 500 to 900°C for 60 to 180 minutes.

3. In paragraph 1, The above electrode active material includes a porous carbon support, A secondary battery electrode material, wherein the silicon is disposed on the surface and inside the pores of the porous carbon support.

4. In paragraph 1, A secondary battery electrode material, wherein the electrode active material comprises a non-porous carbon support containing at least one of hard carbon and soft carbon.

5. In paragraph 1, A secondary battery electrode material, wherein the first coating layer has a thickness of 10 to 400 nm.

6. In paragraph 1, A secondary battery electrode material, wherein the second coating layer comprises carbonized petroleum-based pitch or carbon.

7. In paragraph 1, A secondary battery electrode material, wherein the second coating layer has a thickness of 10 to 400 nm.

8. Electrode active material containing silicon (Si); and A coating layer coated on the surface of the electrode active material; A secondary battery electrode material, wherein the coating layer comprises carbonized petroleum-based pitch and has a thickness of 10 to 95 nm.

9. In paragraph 1, The secondary battery is a secondary battery electrode material, which is a lead (Pd) storage battery, a nickel-cadmium (NiCd) battery, a nickel-metal (Ni-metal) hydrogen battery, a lithium ion (Li-ion) battery, a solid-state battery, a soft carbon battery, a hard carbon battery, or a lithium ion polymer (Li-ion polymer) battery.

10. In paragraph 1, The above electrode active material is a negative electrode active material, a secondary battery electrode material.

11. In paragraph 1, The above secondary battery electrode material is a secondary battery negative electrode material.

12. A first step of forming a first coating layer on the surface of the electrode active material by coating the surface of the electrode active material with petroleum pitch; A second step of carbonizing an electrode active material having a first coating layer formed on the surface; A third step of forming a second coating layer on the surface of the carbonized first coating layer by coating petroleum pitch on the surface of the carbonized first coating layer; and A fourth step of manufacturing a secondary battery negative electrode material by carbonizing a negative electrode active material on which a first coating layer and a second coating layer are sequentially formed on the surface; A method for manufacturing a secondary battery electrode material, comprising:

13. A first step of forming a first coating layer on the surface of an electrode active material by coating the surface of the electrode active material with petroleum pitch; A second step of carbonizing an electrode active material having a first coating layer formed on the surface; and A third step of manufacturing a secondary battery negative electrode material by forming a second coating layer made of carbon on the surface of the carbonized first coating layer; A method for manufacturing a secondary battery electrode material, comprising:

14. A first step of forming a coating layer on the surface of the electrode active material by coating the surface of the electrode active material with petroleum pitch; and A second step of manufacturing a secondary battery negative electrode material by carbonizing an electrode active material having a coating layer formed on the surface and then performing a CIP (Cold Isostatic Pressing) method; A method for manufacturing a secondary battery electrode material, comprising:

15. A first step of forming a first coating layer on the surface of the electrode active material by coating petroleum pitch on the surface of the electrode active material and then performing the CIP (Cold Isostatic Pressing) method; A second step of carbonizing an electrode active material having a first coating layer formed on the surface; A third step of forming a second coating layer on the surface of the carbonized first coating layer by coating petroleum pitch on the surface of the carbonized first coating layer; and A fourth step of manufacturing a secondary battery negative electrode material by carbonizing a negative electrode active material on which a first coating layer and a second coating layer are sequentially formed on the surface; A method for manufacturing a secondary battery electrode material, comprising:

16. In any one of paragraphs 12 to 15, A method for manufacturing a secondary battery electrode material, wherein the coating in the first step is dry coating using a mechano-fusion method.

17. In any one of paragraphs 12 to 15, A method for manufacturing a secondary battery electrode material, wherein the carbonization in the second step is performed at a temperature of 500 to 900°C for 60 to 180 minutes.

18. In paragraph 12 or paragraph 15, A method for manufacturing a secondary battery electrode material, wherein the carbonization in the fourth step is performed at a temperature of 500 to 900°C for 60 to 180 minutes.

19. In paragraph 13, the third step is A method for manufacturing a secondary battery electrode material, wherein a second coating layer made of carbon is formed on the surface of a carbonized first coating layer using the CVD (Chemical Vapor Deposition) method.

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