Heteroatom-doped carbon support composition, method for preparing same, heteroatom-doped carbon support, carbon-silicon composite particles comprising same, all-solid-state battery comprising same, and lithium ion battery comprising same

Abstract

The present invention relates to a heteroatom-doped porous carbon support composition and, more particularly, to a heteroatom-doped porous carbon support composition, a method for preparing same, a heteroatom-doped porous carbon support, carbon-silicon composite particles comprising same, an all-solid-state battery comprising same, and a lithium ion battery comprising same.

Description

Heterogeneous element-doped carbon support composition, method for preparing the same, heterogeneous element-doped carbon support, carbon-silicon composite particles comprising the same, all-solid-state battery comprising the same, and lithium-ion battery comprising the same

[0001] The present invention relates to carbon-silicon composite particles used as a negative electrode material for a secondary battery such as a lithium-ion battery and / or an all-solid-state battery, a carbon support used in producing the composite particles, 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 active material.

[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 silicon, one of the anode components, to fragment during charging and discharging, resulting in significantly reduced mechanical stability.

[0005] Additionally, the introduction of carbon materials as a support for the above silicon-based negative electrode material is being attempted and developed.

[0006] Carbon materials are materials composed of carbon, one of the most abundant resources on Earth. Carbon materials are extremely lightweight, strong, and possess excellent electrical and thermal conductivity, making them a key material widely used in fields such as hydrogen vehicles, aviation, secondary batteries, and high-end consumer goods. Carbon materials can be manufactured from a variety of raw materials, including coconut shells, polyacrylonitrile, rayon, and pitch. However, carbon materials manufactured from solid raw materials like coconut shells are difficult to control in terms of molecular weight and composition (Korean Patent Application Publication No. 10-2019-0093960).

[0007] On the other hand, pitch, a viscoelastic solid polymer extracted from crude oil or plants, has the advantages of high yield when converted into carbon materials, low cost of raw materials, and its molecular structure is closer to the graphite structure than other raw materials, which reduces the energy required for heat treatment (U.S. Patent Nos. 4,242,196 and 4,340,464).

[0008] In particular, pyrolysis fuel oil (PFO), naphtha cracking bottom oil (NCB), vacuum residue (VR), and fluid catalytic cracking decant oil (FCC-DO), which are obtained as by-products in the petroleum refining process, have a high content of aromatic compounds and a low content of impurities such as sulfur and nitrogen, and therefore pitch manufactured from them is attracting attention as a material for carbon materials.

[0009] Conventional carbon supports used as anode materials for secondary batteries are composed of amorphous carbon-based materials, which have the disadvantage of low electrical conductivity. As a result, anode materials manufactured with conventional carbon supports have limitations in high-rate characteristics due to poor electron and Li ion transport. To solve this problem, the inventors of the present invention have discovered the optimal conditions for introducing a specific heterogeneous element as a doping component into the carbon support to improve electrical conductivity, thereby completing the present invention. That is, the present invention provides a carbon support doped with a specific heterogeneous element, and a method for manufacturing carbon-silicon composite particles that can be applied as an anode material.

[0010] To solve the above problem, the present invention provides a heterogeneous element doped carbon support composition comprising a heterogeneous element precursor including a boron (B) precursor and a carbon precursor included in an amount greater than the amount of the heterogeneous element precursor.

[0011] According to a preferred embodiment of the present invention, the boron precursor may include at least one selected from boric acid, boron oxide, sodium borohydride, phenylboronic acid, 4-hydroxyphenylboronic acid, borazine, boron carbide, and triphenylborane.

[0012] Additionally, the heterogeneous element precursor may be included in an amount of 1 to 100 parts by weight per 100 parts by weight of the carbon precursor.

[0013] Additionally, the heterogeneous element precursor may be included in an amount of 11 to 100 parts by weight per 100 parts by weight of the carbon precursor.

[0014]

[0015] In addition, the present invention provides a heterogeneous element doped carbon support including a surface layer and a deep layer, and doped with a heterogeneous element including boron (B).

[0016] According to a preferred embodiment of the present invention, the heterogeneous element doped carbon support may be a non-porous carbon support including at least one of hard carbon and soft carbon, doped with a heterogeneous element including boron.

[0017] In addition, the above heterogeneous element doped carbon support may be a porous carbon support doped with a heterogeneous element including boron.

[0018] Additionally, the boron (B) and carbon (C) contents measured through SEM-EDS analysis can satisfy the following equation 1.

[0019] [Formula 1]

[0020] 0.001 ≤ B / C ≤ 0.3

[0021] In Equation 1, B is the content (weight %) of boron (B) in the heterogeneous element doped carbon support analyzed by SEM-EDS, and C is the content (weight %) of carbon (C) in the heterogeneous element doped carbon support analyzed by SEM-EDS.

[0022]

[0023] In addition, the present invention provides a method for producing a heterogeneous element-doped carbon support, characterized by comprising the steps of (1) producing a heterogeneous element-doped carbon support composition by mixing a heterogeneous element precursor including a boron-based precursor and a carbon precursor in an amount greater than the amount of the heterogeneous element precursor, (2) stabilizing the composition, and (3) carbonizing the stabilized composition to obtain a carbonized body.

[0024] According to a preferred embodiment of the present invention, after step (3), a step (4) of activating the carbonized body may be further included.

[0025]

[0026] In addition, the present invention provides a carbon-silicon composite particle including the above-described heterogeneous element doped carbon support and silicon arranged on the surface of the heterogeneous element doped carbon support.

[0027]

[0028] In addition, the present invention provides an all-solid-state battery characterized by having a negative electrode including the above-described carbon-silicon composite particles.

[0029]

[0030] In addition, the present invention provides a lithium ion battery characterized by having a negative electrode including the above-described carbon-silicon composite particles.

[0031] When the heterogeneous element doped carbon support of the present invention is applied as a negative electrode material, it can improve the high-rate characteristics of a secondary battery compared to existing negative electrode materials.

[0032] Figure 1 is a high-rate characteristic specific graph of a manufacturing example and a comparative manufacturing example of the present invention.

[0033] In this specification, expressions such as “has”, “may have”, “includes”, or “may include” indicate the presence of a feature (e.g., a component such as a number, function, operation, or part), and do not exclude the presence of additional features.

[0034] In this specification, expressions such as "A or B," "at least one of A and / or B," or "one or more of A or / and B" can include all possible combinations of the listed items. For example, "A or B," "at least one of A and B," or "at least one of A or B" can all refer to (1) including at least one A, (2) including at least one B, or (3) including both at least one A and at least one B.

[0035] 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.

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

[0037] The heterogeneous element doped carbon support of the present invention is manufactured by performing a process including: (1) preparing a heterogeneous element doped carbon support composition by mixing a heterogeneous element precursor including a boron (B) precursor and a carbon precursor included in an amount greater than the heterogeneous element precursor; (2) stabilizing the composition; and (3) carbonizing the stabilized composition to obtain a carbonized body.

[0038] Additionally, after the step (3), a step (4) of activating the carbonized body may be further included.

[0039] Step (1)

[0040] The heterogeneous element doped carbon support composition of step (1) includes a heterogeneous element precursor including a boron-based precursor and a carbon precursor included in an amount greater than the amount of the heterogeneous element precursor.

[0041] In the above composition, the heterogeneous element precursor includes a boron (B) precursor.

[0042] The above boron-based precursor may include at least one selected from boric acid, boron oxide, sodium borohydride, phenylboronic acid, 4-hydroxyphenylboronic acid, borazine, boron carbide, and triphenylborane, and preferably may include at least one selected from boric acid, boron oxide, and sodium borohydride.

[0043] And, the content of the heterogeneous element precursor in the composition may be 1 to 100 parts by weight, preferably 11 to 100 parts by weight, and more preferably 42 to 100 parts by weight, based on 100 parts by weight of the carbon precursor.

[0044] At this time, if the content of the heterogeneous element precursor in the composition is less than 1 part by weight based on 100 parts by weight of the carbon precursor, the amount of the heterogeneous element doped in the carbon support may be too small, resulting in a problem of insufficient improvement in the electrical properties of the heterogeneous element-doped carbon support. If it exceeds 100 parts by weight, there may be a problem of performance deviation of the electrode occurring due to a decrease in the uniformity of doping in the heterogeneous element-doped carbon support and interference with pore control (in the case of a porous carbon support). Therefore, it is recommended to use it within the above range.

[0045] And, the carbon precursor in the composition may be a pitch synthesized by thermal decomposition and polycondensation of a petroleum-based raw material. In a specific embodiment of the present invention, the petroleum-based raw material may include at least one selected from the group consisting of thermal cracking 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 oil (RFCC-DO), 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 thermal cracking fuel oil.

[0046] In a specific embodiment of the present invention, the softening point of the pitch may be 200°C or higher. Since the pitch has a high softening point, when used as a precursor for producing a carbon support, the stabilization process is easy, and a high yield can be obtained after carbonization and activation. The upper limit of the softening point of the pitch may be, for example, 350°C or lower, 330°C or lower, or 300°C or lower, but is not limited thereto.

[0047] Meanwhile, the pitch synthesized by thermal decomposition and polycondensation of the petroleum-based raw material may be a liquid pitch, in which case the step of solidifying the liquid pitch to produce a solid pitch may further be included. The liquid pitch may be solidified, for example, by extrusion and cooling. The process of extruding and cooling the liquid pitch to obtain a solid pitch may be performed using commercialized equipment. For example, this process may be performed using a double belt cooler & flaker manufactured by IPCO, but is not particularly limited to this equipment.

[0048] The solidified pitch may have an average particle size of 1 to 30 mm, preferably 5 to 25 mm. When the average particle size of the pitch is within this range, the pitch can be effectively used for various purposes when a carbon support is produced through a series of steps described below using the pitch directly.

[0049]

[0050] Step (2)

[0051] Step (2) of the method for producing a heteroatom-doped carbon support according to the present invention is a step of stabilizing the composition produced in step (1). Specifically, it is a step of stabilizing the carbon structure of the pitch by first oxidizing the pitch in the mixture.

[0052] 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 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.

[0053] In a specific embodiment of the present invention, the stabilization of the pitch can be performed at a pressure of 0.1 to 10 bar, preferably 0.5 to 5 bar. When the stabilization of the pitch is performed at this pressure, the structure of the pitch can be sufficiently stabilized, even to the carbon inside the pitch.

[0054] In a specific embodiment of the present invention, the stabilization of the pitch 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 of the pitch is performed under these oxidizing gas flow rates, the structure of the pitch, including the carbon within the pitch, can be sufficiently stabilized.

[0055] In a specific embodiment of the present invention, the pitch stabilization may be performed for 1 to 10 hours, preferably 2 to 8 hours. If the pitch stabilization is performed for this period of time, the structure of the pitch, including the carbon within the pitch, can be sufficiently stabilized.

[0056]

[0057] Step (3)

[0058] Step (3) of the method for producing a heterogeneous element doped carbon support according to the present invention is a step of carbonizing a stabilized composition to obtain a carbonized body.

[0059] In addition, the carbonization treatment may be performed under an inert gas atmosphere. In a preferred embodiment of the present invention, the carbonization treatment may be performed under a nitrogen or argon atmosphere, but is not particularly limited thereto.

[0060] Meanwhile, the heterogeneous element doped carbon support according to the present invention may be one in which a heterogeneous element including boron is doped into at least one of a non-porous carbon support and a porous carbon support, and more preferably, one in which a heterogeneous element including boron is doped into at least one of graphite, hard carbon, soft carbon, and porous carbon support, and even more preferably, one in which a heterogeneous element including boron is doped into at least one of hard carbon, soft carbon, and porous carbon support, may be more advantageous in achieving the purpose of the present invention.

[0061] When the above heterogeneous element doped carbon support is one in which a heterogeneous element including boron is doped into at least one of a hard carbon and a porous carbon support, the carbonization treatment may be performed at a temperature of 700 to 1,000°C, preferably 800 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.

[0062] In addition, when the heterogeneous element doped carbon support is a soft carbon doped with a heterogeneous element including boron, the carbonization treatment 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 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.

[0063] In a specific embodiment of the present invention, the carbonization of the pitch can be performed under a flow rate condition of an inert gas, preferably one or more of nitrogen and argon, of 0.01 to 30 L / min, preferably 0.01 to 10 L / min. When the carbonization of the pitch is performed under these inert gas flow rate conditions, the pitch can be sufficiently carbonized.

[0064] In a specific embodiment of the present invention, the carbonization of the pitch may be performed for 0.5 to 5 hours, preferably 1 to 3 hours. If the carbonization of the pitch is performed for this period of time, the pitch can be sufficiently carbonized.

[0065]

[0066] Step (4)

[0067] The method for manufacturing a heterogeneous element-doped porous carbon support according to the present invention may further include, after step (3), a step (4) of activating the carbonized body, when the heterogeneous element-doped carbon support is a porous carbon support doped with a heterogeneous element including boron. In step (4), the carbonized body is activated to form and increase porosity within the carbon support.

[0068] Activation of the carbonized body may be performed in an oxidizing gas atmosphere. In a preferred embodiment of the present invention, activation of the carbonized body may be performed in a steam atmosphere, but is not particularly limited thereto.

[0069] Additionally, activation of the carbonized body can be performed at a temperature of more than 500°C and less than 1,000°C or between 800°C and 1,000°C. When 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.

[0070] Additionally, activation of the carbonized body can be performed at a pressure of 0.1 to 10 bar, preferably 0.1 to 5 bar. When activation of the carbonized body is performed at this pressure, a porous carbon support with sufficiently formed pores can be obtained.

[0071] Additionally, the activation of the carbonized body can 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 heterogeneous element-doped porous carbon support with sufficiently formed pores can be obtained.

[0072]

[0073] In the manufacturing method of the present invention, steps (2) to (3) or steps (2) to (4) above can be performed continuously in one device. For example, steps (2) to (3) or steps (2) to (4) above can be performed continuously in one rotary kiln, but are not particularly limited to this device. Since stabilization, carbonization, and activation are performed continuously in one device, optimization of the process can be easily achieved.

[0074] Meanwhile, when the heterogeneous element doped carbon support is a soft carbon doped with a heterogeneous element including boron, steps (2) to (3) may be performed as a series of steps in a rotary kiln, or may be performed as a series of steps by placing the support 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 support in a crucible and placing it in an oven.

[0075] In a specific embodiment of the present invention, the heteroelement-doped carbon support obtained through the above series of steps may be further pulverized or ground and classified. The carbon support can be further finely divided through pulverization or grounding, and the particle size distribution of the carbon support can be made uniform through classification. Here, the classification may be dry classification, wet classification, or classification using a sieve. Through the pulverization or pulverization and classification treatment, a carbon support powder doped with a heteroelement having an average diameter of 1 to 200 μm can be obtained.

[0076]

[0077] In addition, the heterogeneous element doped carbon support according to the present invention includes a surface portion and a core portion, and is characterized in that it is doped with a heterogeneous element including boron.

[0078] When the above heterogeneous element doped carbon support is a porous carbon support doped with a heterogeneous element including boron, the heterogeneous element doped porous carbon support may include a surface portion where pores are formed and a core portion where pores are formed, and may be doped with a heterogeneous element including boron.

[0079] The BET specific surface area of ​​the heteroatom-doped carbon support according to the present invention may be in the range of 300 m2 / g to 3000 m2 / g. The BET specific surface area of ​​the 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 results of N2 / 77K Isotherm adsorption according to ISO9277 can be calculated using the BET equation and the BJH equation. The BET specific surface area of ​​the above heterogeneous element doped carbon support may be 300 ㎡ / g or more, 400 ㎡ / g or more, or 500 ㎡ / g or more, and it may be more advantageous to achieve the purpose of the present invention when it is 3,000 ㎡ / g or less, 2,800 ㎡ / g or less, 2,600 ㎡ / g or less, 2,000 ㎡ / g or less, or 1,200 ㎡ / g or less. In particular, when the heterogeneous element doped carbon support is a porous carbon support doped with a heterogeneous element including boron, if the BET specific surface area of ​​the heterogeneous element doped porous carbon support is excessively low, the ratio of macropores may increase, which may lower the mechanical strength of the negative electrode material, and there may be a lack of effective pores. Additionally, if the BET surface area of ​​the porous carbon support is too high, the proportion of micropores may increase, and silicon may not be sufficiently deposited deep within the porous carbon support.

[0080] And, the carbon support may have a diameter of 200 μm or less. The diameter may refer to the D50 diameter. Specifically, it may refer to an average value obtained by dispersing the carbon support in ethanol and then performing particle size analysis three times. The diameter of the carbon support may be 200 μm or less, 150 μm or less, 100 μm or less, 80 μm or less, or 50 μm or less, and may be 1 μm or more, 2 μm or more, 3 μm or more, 4 μm or more, or 5 μm or more, but is not limited thereto.

[0081]

[0082] As described above, the heterogeneous element doped carbon support of the present invention can satisfy the following equation 1 in terms of boron (B) and carbon (C) contents measured through SEM-EDS analysis.

[0083] [Formula 1]

[0084] 0.001 ≤ B / C ≤ 0.3

[0085] In Equation 1, B is the content (weight %) of a heterogeneous element, preferably boron (B), in the heterogeneous element-doped carbon support analyzed by SEM-EDS, and C is the content (weight %) of carbon (C) in the heterogeneous element-doped carbon support analyzed by SEM-EDS.

[0086]

[0087] In addition, the present invention provides a carbon-silicon composite particle including the above-described heterogeneous element doped carbon support and silicon arranged on the surface of the heterogeneous element doped porous carbon support.

[0088] When the above heterogeneous element doped carbon support is a porous carbon support doped with a heterogeneous element including boron, the silicon can be arranged on the surface and inside the pores of the heterogeneous element doped porous carbon support.

[0089] When the above carbon-silicon composite particles are applied to a battery cathode, the effect of improved electrical conductivity and improved high-rate characteristics is achieved.

[0090] Meanwhile, as described above, since the heterogeneous element doped carbon support includes a surface portion and a deep portion, and especially, when the heterogeneous element doped carbon support is a porous carbon support doped with a heterogeneous element including boron, since it includes a surface portion in which pores are formed and a deep portion in which pores are formed, silicon arranged inside the pores of the heterogeneous element doped porous carbon support in the carbon-silicon composite particles may be deposited and present in the surface portion and / or the deep portion of the heterogeneous element doped porous carbon support.

[0091] Since the carbon-silicon composite particles according to the present invention have the above structure, when the carbon-silicon composite particles according to the present invention are applied to a battery negative electrode, there is an effect of stably improving high-rate characteristics due to high electrical conductivity.

[0092] In another example, the silicon content of the carbon-silicon composite particles according to the present invention may be 1 wt% or more based on the total weight of the carbon-silicon composite particles. The silicon content of the carbon-silicon composite particles may be a value obtained by analysis using an energy dispersive spectrometer (EDS). The silicon content in the carbon-silicon composite particles may be 10 wt% or more, 15 wt% or more, 20 wt% or more, 25 wt% or more, or 30 wt% or more, but is not limited thereto. In addition, the silicon content of the carbon-silicon composite particles may be 60 wt% or less, 58 wt% or less, 56 wt% or less, 54 wt% or less, 52 wt% or less, or 50 wt% or less, but is not limited thereto. If the silicon content of the carbon-silicon composite particles is too low, the electric capacity may decrease, and if the silicon content is too high, the volume expansion rate of the silicon may increase during charge and discharge, which may cause structural damage to the negative electrode material and deteriorate the cycle characteristics.

[0093]

[0094] The carbon-silicon composite particles described above can be manufactured by the following method.

[0095] The carbon-silicon composite particles of the present invention can be manufactured by performing a process including the steps of (a) preparing a heterogeneous element-doped carbon support; and (b) depositing silicon (Si) on the heterogeneous element-doped carbon support.

[0096] (a) The carbon support of step (a) can be a commercially available one, and preferably, one having the manufacturing method and properties described above can be used.

[0097] (b) The above deposition in step can be performed at a temperature of 300°C to 600°C and under a silane (SiH4) gas atmosphere.

[0098] In a preferred embodiment, the heteroatom-doped carbon support may be deposited at a temperature of 300°C to 600°C under a silane (SiH4) gas atmosphere. The deposition may be performed, for example, using chemical vapor deposition (CVD) and under atmospheric pressure, but is not limited thereto. Through the deposition, silicon may be deposited, including on the surface of the heteroatom-doped carbon support according to the present invention.

[0099]

[0100] The carbon-silicon composite particles of the present invention described above can be applied to a cathode, and preferably can be applied as a battery cathode material, and the battery cathode material can have improved high-rate characteristics due to improved electrical conductivity.

[0101] The method for manufacturing the above-mentioned battery negative electrode material is not particularly limited, and can be manufactured using a general method for manufacturing battery negative electrode materials. For example, the above-mentioned battery negative electrode material can be manufactured by mixing carbon-silicon (C-Si) composite particles, an active material, a conductive material, a binder, etc., and coating / drying / rolling the mixture onto a component such as an electrode current collector, but is not limited thereto.

[0102] The present invention also provides a secondary battery having a negative electrode including the carbon-silicon composite particles described above, such as a lithium-ion battery or an all-solid-state battery.

[0103] The lithium ion battery may specifically include a positive electrode, a negative electrode, a separator, and an electrolyte. At this time, the negative electrode may include the above-described battery negative electrode material. The positive electrode may use a material usable in a lithium ion battery, and may include, for example, one or more positive electrode active materials selected from doped or undoped lithium nickel oxide, lithium cobalt oxide, lithium cobalt aluminum oxide, lithium nickel cobalt manganese oxide, lithium manganese oxide, and lithium nickel cobalt aluminum oxide, and a positive electrode current collector selected from aluminum, stainless steel, nickel, titanium, platinum, or an alloy thereof, but is not limited thereto. In addition, the separator may use a typical separator usable in a lithium ion battery. The separator may include, for example, one or more selected from glass fiber, polyester, Teflon, polyethylene, polypropylene, and polytetrafluoroethylene (PTFE), but is not limited thereto.

[0104] The negative electrode of the lithium ion battery may include the above-described battery negative electrode material. The negative electrode may include a negative electrode current collector and a battery negative electrode material, and the negative electrode current collector may include one or more selected from aluminum, stainless steel, nickel, titanium, platinum, or an alloy thereof, but is not limited thereto.

[0105] The electrolyte of the above lithium ion battery may include, but is not limited to, an organic liquid electrolyte, an inorganic liquid electrolyte, a polymer electrolyte, or a molten inorganic electrolyte usable in a lithium ion battery.

[0106] The above-mentioned all-solid-state battery may specifically include a positive electrode, a negative electrode, and a solid electrolyte, and may further include a separator as needed, but is not limited thereto. The positive electrode may include the above-mentioned positive electrode active material, and may include a positive electrode current collector as needed, but is not limited thereto.

[0107] The above-described negative electrode may include the above-described battery negative electrode material. The above-described negative electrode may have a single-layer structure including the above-described battery negative electrode material, or may further include a negative electrode current collector as needed, but is not limited thereto.

[0108] The solid electrolyte may optionally use a solid electrolyte usable in an all-solid-state battery. The solid electrolyte may be, for example, at least one selected from the group consisting of a Garnet-type, a Nasicon-type, a LISICON-type, a perovskite-type, and a LiPON-type, but is not limited thereto.

[0109]

[0110] 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.

[0111] [Example]

[0112] Preparation Example 1: Preparation of a heterogeneous element-doped porous carbon support

[0113] 300 g of petroleum residue oil (YNCC, HTC PFO (pyrolysis fuel oil)) was introduced into 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 to 30 mm.

[0114] The solid pitch pellets obtained above were pulverized to obtain powdered pitch (carbon precursor).

[0115] Next, a heterogeneous element doped porous carbon support composition was prepared by mixing 42.85 parts by weight of boric acid as a heterogeneous element precursor with 100 parts by weight of the carbon precursor.

[0116] The manufactured composition was placed in a rotary kiln and sequentially subjected to stabilization, carbonization, and activation.

[0117] The conditions for stabilization, carbonization, and activation are as shown in Table 1 below. The activated carbonized body, after the above activation, was pulverized using a pulverizer (NETZSCH, air jet mill) to produce a heterogeneous element doped porous carbon support.

[0118] Step Condition Preparation Example 1 Stabilization temperature (℃) 320 hours (hr) 2 Atmosphere air carbonization temperature (℃) 900 hours (hr) 1 Atmosphere nitrogen activation temperature (℃) 900 hours (hr) 3 Steam flow rate (ml / min) 100

[0119]

[0120] Preparation Example 2

[0121] A heterogeneous element doped porous carbon support was manufactured using the same method and composition as in Preparation Example 1 above, but 100 parts by weight of boric acid was used per 100 parts by weight of the carbon precursor.

[0122]

[0123] Comparison Preparation Example 1

[0124] A heterogeneous element doped porous carbon support was manufactured using the same method and composition as in Preparation Example 1 above, but 150 parts by weight of boric acid was used per 100 parts by weight of the carbon precursor.

[0125]

[0126] Comparison Preparation Example 2

[0127] A porous carbon support was manufactured using the same method and composition as in Preparation Example 1 above, but 100 wt% of powdered pitch was mixed, stabilized, carbonized, and activated to manufacture a porous carbon support (without heterogeneous element doping).

[0128]

[0129] Experimental Example 1: Analysis of surface area and pore characteristics of heterogeneous element-doped porous carbon supports.

[0130] The properties of the porous carbon supports of Preparation Examples 1 to 2 and Comparative Preparation Examples 1 to 2 were measured, and the results are shown in Table 2 below.

[0131] The specific surface area was measured using a gas adsorption analyzer (ASAP 2420, Micromeritics) according to the ASTM D4820-93 method.

[0132] Preparation Example 1 Preparation Example 2 Comparison Preparation Example 1 Comparison Preparation Example 2 Specific surface area (m 2 / g)9889669311201Total pore volume (cm) 3 / g)0.640.620.600.71

[0133]

[0134] Experimental Example 2: SEM-EDS Analysis of Heterogeneous Element-Doped Porous Carbon Support

[0135] SEM-EDS analysis was performed on the porous carbon supports manufactured in Preparation Examples 1 to 2 and Comparative Preparation Examples 1 to 2, and the content of heterogeneous elements and carbon (C) in the porous carbon supports were calculated, and the results are shown in Table 3 below.

[0136] In addition, the ratio of the heterogeneous element (boron) content and carbon content was calculated according to Equation 1 below.

[0137] [Formula 1]

[0138] 0.001 ≤ B / C ≤ 0.3

[0139] In Equation 1, B is the content (weight %) of the heterogeneous element (boron) in the heterogeneous element-doped porous carbon support analyzed by SEM-EDS, and B is the content (weight %) of carbon (C) in the heterogeneous element-doped porous carbon support analyzed by SEM-EDS.

[0140] Preparation Example 1 Preparation Example 2 Comparison Preparation Example 1 Comparison Preparation Example 2 Heterogeneous element content (wt%) 3.4 6.18 10.1 C content (wt%) 95.4 93.19 0.2 9 6.7 Heterogeneous element / carbon ratio 0.04 0.07 0.090

[0141]

[0142] Example 1: Preparation of carbon-silicon composite particles and silicon-carbon composites

[0143] (1) Manufacturing of carbon-silicon (C-Si) composite particles

[0144] Carbon-silicon composite particles were prepared using the heterogeneous element-doped porous carbon support prepared in Preparation Example 1. 18.0 g of the heterogeneous element-doped porous carbon support powder was placed in a rotary kiln, and silane (SiH4) gas was injected to deposit the porous carbon support.

[0145] During silane gas deposition, the pressure was atmospheric pressure and the deposition was performed at a temperature of 475°C. The physical properties of the manufactured carbon-silicon composite particles are shown in Table 4 below.

[0146]

[0147] Comparative Examples 1 to 3

[0148] (1) Comparative Example 1 is a commercial product (Ingevity) with a diameter of 4.28 ㎛ as a porous carbon support. ®Carbon-silicon composite particles were manufactured in the same manner as in Example 1, except that a carbon-silicon composite particle (product name BAX1500, USA) was used.

[0149] (2) In addition, Comparative Example 2 produced carbon-silicon composite particles using the same method and conditions as Example 1, but used the heterogeneous element doped porous carbon support of Comparative Preparation Example 1 instead of the B-doped porous carbon support of Preparation Example 1.

[0150] (3) In addition, Comparative Example 3 produced carbon-silicon composite particles using the same method and conditions as Example 1, but used the porous carbon support of Comparative Preparation Example 2 instead of the B-doped porous carbon support of Preparation Example 1.

[0151] Classification Example 1 Comparative Example 1 Comparative Example 2 Comparative Example 3 Porous carbon support (before deposition) Particle size distribution D50 (㎛) 5.6 4.3 5.9 5.5 Specific surface area (m 2 / g)98819349311010Tab density (g / ml)0.390.210.40.42Carbon-silicon composite particles (after deposition)Particle size distribution D50 (㎛)65.56.25.5Specific surface area (m 2 / g)16641319Tab density (g / ml)0.670.60.680.61Silicon content (wt%)50.144.151.148.2

[0152]

[0153] Experimental Example 3: Electrochemical Evaluation of Secondary Batteries

[0154] Half coin cells were manufactured using each of the carbon-silicon composite particles of Example 1 and Comparative Examples 1 to 3 manufactured previously as a negative electrode material, and Manufacturing Example 1 and Comparative Manufacturing Examples 1 to 3 were performed as shown in Table 5.

[0155] A slurry was prepared by mixing carbon-silicon composite particles, conductive material, and binder in a ratio of 8:1:1. At this time, the conductive material used was super-P, and the binder used was a mixture of styrene butadiene rubber (SBR) and sodium carboxymethyl cellulose (CMC) in a weight ratio of 5:5.

[0156] Next, the slurry was uniformly applied to copper foil and dried in an equal amount in an 80°C oven for 1 hour. After the primary drying, the slurry was roll-pressed and dried in a 120°C vacuum oven for 6 hours and 30 minutes to manufacture a negative electrode plate.

[0157] A half coin cell was manufactured using the above-mentioned negative electrode and lithium foil as a counter electrode. A porous polyethylene film was used as a separator, and a CR2032 half coin cell (half cell) was manufactured under the conditions shown in Table 5 below.

[0158] The electrolyte was prepared by dissolving 1.3 M LiPF6 in a solvent containing ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC) in a volume ratio of 3:5:2, and dissolving 10 wt% fluoro-ethylene carbonate (FEC), 0.2 wt% lithium tetrafluoroborate (LiBF4), 0.5 wt% vinylene carbonate (VC), and 1 wt% propane sulton (PS) as additives (see Table 5).

[0159] Composition (AM:CM:BM) 8:1:1 Area capacity (mAh / cm 2)1 Electrolyte 1.3M LiPF6 EC / EMC / DMC 3:5:2, FFC 10%, LiBF4 0.2%, 0.5% VC, 1% PS Cut-off voltage (V) Formation: 0.005 ~ 1.5, Cycle test: 0.005 ~ 1.5 C-rate (C) Formation: 0.1 ~ 0.1. 0.01 C cut-off (CV) at 0.005 V

[0160] In Table 5 above, AM, CM, and BM represent active material (carbon-silicon composite particles), 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.

[0161] Electrochemical analysis was performed on the manufactured half coin cell under the following conditions.

[0162] Cut off voltage (V): 0.005 - 1.5V (Formation), 0.005 - 1.2V(Cycle)

[0163] Formation C-rate (C): 0.1C lithiation, 0.1C delithiation

[0164] Cycle C-rate (C): 0.5C lithiation, 0.5C delithiation

[0165] The results are shown in Table 6 below.

[0166] In addition, the high-rate characteristics were evaluated by calculating the discharging retention (%) in the range of 0.1C to 2.0C, and the results are shown in Fig. 1.

[0167] Classification Initial Half Cell C-Si Composite Recharge Capacity (mAh / g) Discharge Capacity (mAh / g) ICE (%) Manufacturing Example 1 Example 1 1988175288 Comparative Manufacturing Example 1 Comparative Example 1 1633135583 Comparative Manufacturing Example 2 Comparative Example 2 1957170187 Comparative Manufacturing Example 3 Comparative Example 3 1888161085

[0168] As can be seen in Table 6 above, Manufacturing Example 1, which applied carbon-silicon composite particles manufactured through the heterogeneous element doped porous carbon support of the present invention to the negative electrode, was found to exhibit significantly superior charge-discharge efficiency compared to Comparative Manufacturing Example 1, which used a commercial porous carbon support instead of the heterogeneous element doped porous carbon support, Comparative Manufacturing Example 2, which applied Comparative Preparation Example 1 exceeding the range of the heterogeneous element precursor content in the composition, and Comparative Manufacturing Example 3, which used a porous carbon support (without heterogeneous element doping) instead of the heterogeneous element doped porous carbon support.

[0169] Meanwhile, as the rate increases, the discharge capacity decreases. As shown in Fig. 1, when doped with boron (B), the electrical conductivity increases, and the structural stability is improved compared to the case of no doping or unsatisfactory content range, so it was confirmed that the decrease in discharge capacity is small even under high-rate conditions.

[0170]

[0171] While the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments and the attached drawings, but is intended to be defined by the appended claims. Accordingly, those skilled in the art will appreciate that various substitutions, modifications, and alterations may be made without departing from the technical spirit of the present invention as defined in the claims, and such modifications are also within the scope of the present invention.

Claims

1. A heteroelement precursor containing a boron (B) precursor; and A heterogeneous element doped carbon support composition characterized by comprising a carbon precursor contained in an amount greater than the amount of the heterogeneous element precursor.

2. In paragraph 1, A heteroatom-doped carbon support composition characterized in that the boron precursor comprises at least one selected from boric acid, boron oxide, sodium borohydride, phenylboronic acid, 4-hydroxyphenylboronic acid, borazine, boron carbide, and triphenylborane.

3. In paragraph 1, A heterogeneous element doped carbon support composition characterized in that it contains 1 to 100 parts by weight of the heterogeneous element precursor relative to 100 parts by weight of the carbon precursor.

4. In paragraph 1, A heterogeneous element doped carbon support composition characterized in that it contains 11 to 100 parts by weight of the heterogeneous element precursor relative to 100 parts by weight of the carbon precursor.

5. Including the surface and deep layers, A heteroelement doped carbon support characterized by being doped with a heteroelement containing boron (B).

6. In paragraph 5, The above heterogeneous element doped carbon support is a heterogeneous element doped carbon support in which a heterogeneous element including boron is doped into a non-porous carbon support including at least one of hard carbon and soft carbon.

7. In paragraph 5, The above heterogeneous element doped carbon support is a heterogeneous element doped carbon support in which a heterogeneous element including boron is doped into a porous carbon support.

8. In paragraph 5, A heterogeneous element doped carbon support characterized in that the boron (B) and carbon (C) contents measured through SEM-EDS analysis satisfy the following equation 1. [Formula 1] 0.001 ≤ B / C ≤ 0.3 In Equation 1, B is the content (weight %) of boron (B) in the heterogeneous element doped carbon support analyzed by SEM-EDS, and C is the content (weight %) of carbon (C) in the heterogeneous element doped carbon support analyzed by SEM-EDS. 9.(1) A step of preparing a heterogeneous element doped carbon support composition by mixing a heterogeneous element precursor including a boron precursor and a carbon precursor in an amount greater than the amount of the heterogeneous element precursor; (2) a step of stabilizing the composition; and (3) A method for producing a heterogeneous element-doped carbon support, characterized by including a step of carbonizing a stabilized composition to obtain a carbonized body.

10. In paragraph 9, A method for producing a heterogeneous element doped carbon support, characterized in that it further comprises a step of activating the carbonized body (4) after the step (3) above.

11. A heterogeneous element doped carbon support according to any one of clauses 5 to 8; and Carbon-silicon composite particles comprising silicon arranged on a surface of a heterogeneous element-doped carbon support.

12. An all-solid-state battery characterized by comprising a cathode comprising carbon-silicon composite particles according to Article 11.

13. A lithium ion battery characterized by comprising a negative electrode comprising carbon-silicon composite particles according to Article 11.

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