KR20170104035A - Negative electrode active material for lithium ion battery using composite of silicon comprising coal tar pitch and carbon nanofiber, and preparing method thereof - Google Patents

Negative electrode active material for lithium ion battery using composite of silicon comprising coal tar pitch and carbon nanofiber, and preparing method thereof Download PDF

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KR20170104035A
KR20170104035A KR1020160025733A KR20160025733A KR20170104035A KR 20170104035 A KR20170104035 A KR 20170104035A KR 1020160025733 A KR1020160025733 A KR 1020160025733A KR 20160025733 A KR20160025733 A KR 20160025733A KR 20170104035 A KR20170104035 A KR 20170104035A
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pitch
silicon
cnfs
sio
composite
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강용묵
민설희
조미루
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동국대학교 산학협력단
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H01M4/587—Carbonaceous material, e.g. graphite-intercalation compounds or CFx for inserting or intercalating light metals
    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
    • D01F9/00—Artificial filaments or the like of other substances; Manufacture thereof; Apparatus specially adapted for the manufacture of carbon filaments
    • D01F9/08—Artificial filaments or the like of other substances; Manufacture thereof; Apparatus specially adapted for the manufacture of carbon filaments of inorganic material
    • D01F9/12—Carbon filaments; Apparatus specially adapted for the manufacture thereof
    • D01F9/14—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments
    • D01F9/145—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments from pitch or distillation residues
    • D01F9/15—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments from pitch or distillation residues from coal pitch
    • D—TEXTILES; PAPER
    • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
    • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
    • D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
    • D04H1/70—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres characterised by the method of forming fleeces or layers, e.g. reorientation of fibres
    • D04H1/72—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres characterised by the method of forming fleeces or layers, e.g. reorientation of fibres the fibres being randomly arranged
    • D04H1/728—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres characterised by the method of forming fleeces or layers, e.g. reorientation of fibres the fibres being randomly arranged by electro-spinning
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • H01M4/386—Silicon or alloys based on silicon
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries
    • Y02E60/122—

Abstract

The present invention relates to a negative electrode active material for a lithium secondary battery of a silicon-carbon nanofiber composite into which coal tar pitch is introduced, and to a manufacturing method thereof, and more specifically, to silicon-pitch-carbon nanofibers (SiO_x-Pitch-CNFs), which are negative electrode active materials for a lithium secondary battery having superior price competitiveness and improved electroconductivity by substituting a part of polyacrylonitrile (PAN) into the coal tar pitch, and to a method for manufacturing silicon-pitch-carbon nanofibers (SiO_x-Pitch-CNFs), which comprises the following steps: 1) controlling the size of the pitch particles through a grinding process; 2) adding a silicon powder and a pitch powder in a solution in which a polymer is dissolved and mixing the same uniformly; 3) conducting electrospinning using the mixed solution; 4) heat-treating and calcinating the mixture.

Description

피치를 도입한 실리콘-카본 나노섬유 복합체의 리튬이차전지용 음극활물질 및 이의 제조 방법{Negative electrode active material for lithium ion battery using composite of silicon comprising coal tar pitch and carbon nanofiber, and preparing method thereof}[0001] The present invention relates to a negative electrode active material for a lithium secondary battery and a method for manufacturing the negative electrode active material,

본 발명은 리튬이차전지용 음극활물질 및 그 제조 방법에 관한 것으로서, 구체적으로는 실리콘(Si)-피치(Coal tar Pitch)-카본 나노섬유(SiOx-Pitch-CNFs) 복합체를 이용한 리튬이차전지용 음극활물질 및 그 제조 방법에 관한 것이다.The present invention relates to a negative active material and a method of manufacturing the same, specifically, a silicon (Si) - the pitch (Pitch Coal tar) - carbon nano fiber (SiO x -Pitch-CNFs) negative active material using a composite And a manufacturing method thereof.

최근 이차전지는 에너지저장시스템(Energy Storage System) 및 전기차(HEV or EV) 등의 대형 전력저장전지와 휴대전화, 노트북 등의 고성능 소형 에너지원으로 지속적으로 확대되는 추세이다. 이처럼 전자기기의 장시간 연속사용을 목표로 부품의 경량화와 저소비 전력화에 대한 연구뿐만 아니라 안전성 측면에서 매우 강화된 사양이 요구됨으로서 신재생에너지 전력 안정화를 위한 자율 독립전원 기술로서 활용될 수 있다. 이처럼 최근 이차전지 시장은 고용량, 고성능을 가지는 음극활물질의 개발이 필수적이다.Recently, secondary batteries have been continuously expanding into large-capacity power storage batteries such as energy storage systems (HEV or EV) and high-performance compact energy sources such as mobile phones and notebook computers. As a result, it is required to use a high-performance specification in addition to research on reduction of parts weight and low power consumption aiming at long-time continuous use of electronic devices, and thus it can be utilized as an autonomous power supply technology for stabilizing renewable energy. As such, it is essential to develop anode active materials having high capacity and high performance in the secondary battery market.

그러나 현재까지 상용화되어 온 고결정질 탄소계 흑연은 전지의 활물질로서 제반 특성이 우수함에도 불구하고, 리튬의 이론 저장용량(LiC6 기준)이 372 mAh/g으로 제한된다. 이러한 문제점을 극복하기 위해서 보다 많은 리튬 저장 용량을 갖는 음극활물질이 필요하다. However, high-crystalline carbon-based graphite, which has been commercialized to date, is limited to 372 mAh / g based on theoretical storage capacity of lithium (based on LiC 6 ), although it has excellent properties as a battery active material. To overcome this problem, there is a need for an anode active material having a larger lithium storage capacity.

또한, 흑연 외에 고용량이 가능한 음극활물질로는 리튬과 반응하여 합금(alloy)을 형성할 수 있는 실리콘(Si)이 있는데 이는 4,200 mAh/g의 높은 방전용량뿐 아니라 리튬 반응 전위가 0.4 V(Li/Li+)로 매우 낮기 때문에 음극소재로서 적합한 물질로 알려져 있다. 하지만 실리콘(Si)은 리튬 이온의 삽입 시 최대 400 %에 이르는 부피팽창으로 용량이 유지되지 못할 뿐만 아니라 낮은 전자 전도도 등의 문제점이 있다. 따라서 이러한 문제점들을 개선하기 위해 실리콘 (Si)의 나노구조화와 탄소와의 복합화를 통해 음극활물로의 상용화를 위한 연구가 진행되고 있다. In addition to graphite, there is silicon (Si) capable of forming an alloy by reacting with lithium as a negative electrode active material capable of high capacity, which has a high discharge capacity of 4,200 mAh / g and a lithium reaction potential of 0.4 V (Li / Li + ), it is known as a material suitable as a cathode material. Silicon (Si), however, can not maintain its capacity due to the volume expansion up to 400% when inserting lithium ions, and has problems such as low electronic conductivity. Therefore, in order to solve these problems, studies are being conducted to commercialize an anode active material through the nanostructuring of silicon (Si) and the complexation with carbon.

기존에 보고되었던 실리콘-카본 나노섬유(SiOx-CNFs)의 경우 특성은 우수하나 카본의 원료인 PAN의 가격이 매우 비싸고 비결정질 카본형성에 의해 전자 전도도가 낮은 문제 때문에 이를 상용화하기에는 어려움이 따른다. In the case of silicon-carbon nanofibers (SiO x -CNFs) reported previously, the characteristics are excellent, but the cost of PAN, which is a raw material of carbon, is very high and the electron conductivity is low due to amorphous carbon formation.

한편, 탄소계 콜타르 피치(Coal tar Pitch)의 경우 높은 전자 전도도를 지니고 있고, 자원적으로 풍부하며, 가격 또한 저렴하여 상업적으로 유리한 장점을 가지고 있다. On the other hand, the carbon-based coal tar pitch has commercial advantages because it has a high electron conductivity, is abundant in resources, and is cheap in price.

대한민국 등록특허 제 10-1341951호Korean Patent No. 10-1341951

본 발명은 상기 종래 기술의 문제점을 해결하기 위해 창안된 것으로, 폴리아크릴로니트릴(Polyacrylonitrile; PAN)의 일부를 콜타르 피치(Coal tar Pitch)로 대체하여 가격 경쟁력이 우수하며 전자 전도도가 향상되어 보다 개선된 전기화학 특성을 갖는 리튬이차전지용 음극활물질인 실리콘(Si)-피치(Coal tar Pitch)-카본 나노섬유(SiOx-Pitch-CNFs) 및 그 제조 방법을 제공하는 것을 목적으로 한다.The present invention has been made to solve the problems of the prior art, and it is an object of the present invention to provide a method of replacing a part of polyacrylonitrile (PAN) with a coal tar pitch to provide excellent price competitiveness, (Si) -Pitch (Coar tar Pitch) -carbon nanofibers (SiO x -Pitch-CNFs) which is a negative electrode active material for a lithium secondary battery having electrochemical characteristics and a process for producing the same.

또한, 본 발명은 상기 본 발명에 따른 실리콘(Si)-피치(Coal tar Pitch)-카본 나노섬유(SiOx-Pitch-CNFs) 복합체의 음극활물질을 포함하는 리튬이차전지를 제공하는 것을 목적으로 한다.It is another object of the present invention to provide a lithium secondary battery comprising the anode active material of the silicon (Si) -Pitch (Co-tar Pitch) -carbon nanofiber (SiO x -Pitch-CNFs) .

상기 목적을 달성하기 위하여, 본 발명은 탄소 나노 섬유; 피치(Coal tar Pitch) 입자; 및 실리콘(Si) 입자;를 포함하고, 피치 입자와 실리콘 입자가 탄소 나노 섬유에 균일하게 분산되어 섬유 속에 박혀 있는(encapsulated) 것을 특징으로 하는, 실리콘-피치-카본 나노섬유(SiOx-Pitch-CNFs) 복합체를 제공한다.In order to accomplish the above object, the present invention provides a carbon nanofiber comprising: carbon nanofibers; Coal tar pitch particles; Pitch-carbon nanofibers (SiO x -Pitch-carbon nanofibers) characterized in that the pitch particles and the silicon particles are uniformly dispersed in the carbon nanofibers and encapsulated in the fibers. CNFs) complexes.

또한, 본 발명은 상기 본 발명에 따른 실리콘-피치-카본 나노섬유(SiOx-Pitch-CNFs) 복합체를 포함하는 리튬이차전지용 음극활물질을 제공한다.The present invention also provides a negative electrode active material for a lithium secondary battery comprising the silicon-pitch-carbon nanofiber (SiO x -Pitch-CNFs) composite according to the present invention.

또한, 본 발명은 상기 본 발명에 따른 음극활물질을 포함하는 리튬이차전지를 제공한다.The present invention also provides a lithium secondary battery comprising the negative active material according to the present invention.

또한, 본 발명은 상기 본 발명에 따른 피치(Coal tar Pitch)를 분쇄하여 분말화하는 제 1단계; 실리콘 분말과 피치 분말을 고분자를 용해시킨 용액에 균일하게 혼합하는 제 2단계; 혼합 용액을 전기방사하여 나노섬유 혼합물을 제조하는 제 3단계; 및 나노섬유 혼합물을 열처리하여 나노섬유 복합체를 제조하는 제 4단계;를 포함하는, 실리콘-피치-카본 나노섬유(SiOx-Pitch-CNFs) 복합체의 제조 방법을 제공한다. In addition, the present invention relates to a method for pulverizing and pulverizing a pitch pitch according to the present invention; A second step of uniformly mixing the silicon powder and the pitch powder into a solution in which the polymer is dissolved; A third step of electrospinning the mixed solution to produce a nanofiber mixture; And a fourth step of heat treating the nanofiber mixture to produce a nanofiber composite. The present invention also provides a method of manufacturing a silicon-pitch-carbon nanofiber (SiO x -Pitch-CNFs) composite.

아울러, 본 발명은 상기 본 발명에 따른 제조 방법으로 제조된 실리콘-피치-카본 나노섬유(SiOx-Pitch-CNFs) 복합체, 이를 포함하는 음극활물질, 및 상기 음극활물질을 포함하는 리튬이차전지를 제공한다.In addition, the present invention provides a silicon-pitch-carbon nanofiber (SiO x -Pitch-CNFs) composite prepared by the production method according to the present invention, a negative electrode active material containing the same, and a lithium secondary battery comprising the negative active material do.

본 발명의 피치를 도입한 실리콘(Si)-피치(Coal tar Pitch)-카본 나노섬유(SiOx-Pitch-CNFs) 음극활물질의 제조방법으로 제조할 경우, 폴리아크릴로니트릴(Polyaconitile, PAN)의 일부를 피치로 대체하여 가격 경쟁력이 우수하며 전자 전도도가 향상되어 보다 개선된 전기화학 특성을 가질 수 있다.When manufactured by the method of manufacturing a silicon-Si (Co) tar pitch-carbon nanofiber (SiO x -Pitch-CNFs) negative electrode active material to which the pitch of the present invention is introduced, a polyaconitile By replacing some of them with pitch, they have excellent price competitiveness and improved electronic conductivity, so that they can have improved electrochemical characteristics.

또한, 전지의 용량, 수명, 율속특성 및 표면저항이 개선된 실리콘(Si)-피치(Coal tar Pitch)-카본 나노섬유(SiOx-Pitch-CNFs) 음극활물질을 얻을 수 있다.Also, it is possible to obtain a silicon (Si) -pitch (Coar tar Pitch) -carbon nano fiber (SiO x -Pitch-CNFs) negative electrode active material having improved capacity, lifetime, rate-

도 1은 본 발명에 따른 실리콘-피치-카본 나노섬유(SiOx-Pitch-CNFs) 복합체의 구조 분석을 위한 X선 회절 분석 결과를 나타낸 그림이다.
도 2는 본 발명에 따른 실리콘-피치-카본 나노섬유(SiOx-Pitch-CNFs) 복합체의 구조 분석을 위한 라만 분광법을 이용한 분석 결과를 나타낸 그림이다.
도 3은 본 발명에 따른 실리콘-피치-카본 나노섬유(SiOx-Pitch-CNFs) 복합체의 형태를 분석하기 위해 주사전자현미경을 이용하여 관찰한 사진이다:
여기서 도 3(a)는 분쇄를 하지 않은 피치(Pitch), 도 3(b)는 분쇄과정을 거친 피치(Pitch), 도 3(c)는 피치를 포함하지 않은 실리콘(Si)-카본 복합체(SiOx-CNFs), 도 3(d)는 PAN과 피치의 비율이 4:6인 실리콘(Si)-피치(Coal tar Pitch)-카본 복합체(SiOx-Pitch-CNFs), 도 3(e)는 PAN과 피치의 비율이 5:5인 실리콘(Si)-피치(Coal tar Pitch)-카본 복합체(SiOx-Pitch-CNFs), 도 3(f)는 PAN과 피치의 비율이 6:4인 실리콘(Si)-피치(Coal tar Pitch)-카본 복합체(SiOx-Pitch-CNFs)이다.
도 4는 본 발명에 따른 실리콘-피치-카본 나노섬유(SiOx-Pitch-CNFs) 복합체의 실리콘(Si) 잔류 함량을 확인하기 위해 열 분석법을 수행한 결과를 나타낸 그림이다.
도 5는 본 발명에 따른 실리콘-피치-카본 나노섬유(SiOx-Pitch-CNFs) 복합체의 전기화학평가를 위해 충방전에 의한 용량을 분석한 결과를 나타낸 그림이다:
도 5(a)는 첫 사이클의 충전(charge)은 CC/CV 모드로 (CC (constant current)모드 = 0.05 C, CV (constant voltage)모드 = 0.01 C), 방전(discharge)은 CC (constant current)모드로 0.05 C에서 활성화시킨 초기 충방전 결과(voltage profile)를 나타낸 그림이며, 도 5(b)는 첫 사이클 이후의 사이클을 CC (constant current)모드에서 0.2 C로 각각 50사이클(cycle)까지 충방전한 결과를 나타낸 그림이다.
도 6은 본 발명에 따른 실리콘-피치-카본 나노섬유(SiOx-Pitch-CNFs) 복합체의 전기화학평가를 위해 전류밀도 변화에 따른 용량을 분석한 결과를 나타낸 그림이다.
도 7은 본 발명에 따른 실리콘-피치-카본 나노섬유(SiOx-Pitch-CNFs) 복합체의 표면저항을 분석하기 위해 교류 임피던스 분석법을 수행한 결과를 나타낸 그림이다.1 is a graph showing the results of X-ray diffraction analysis for the structural analysis of a silicon-pitch-carbon nanofiber (SiO x -Pitch-CNFs) composite according to the present invention.
2 is a graph showing the results of analysis using Raman spectroscopy for the structural analysis of the silicon-pitch-carbon nanofiber (SiO x -Pitch-CNFs) complex according to the present invention.
FIG. 3 is a photograph of a silicon-pitch-carbon nanofiber (SiO x -Pitch-CNFs) complex according to the present invention observed using a scanning electron microscope to analyze the shape of the composite.
3 (a), 3 (b) and 3 (c) show a pitch without grinding, a pitch after grinding, and a Si-carbon composite without pitch SiO x -CNFs), Figure 3 (d) is the ratio of PAN and pitch 4:06 silicon (Si) - the pitch (pitch Coal tar) - carbonyl complex (SiO x -Pitch-CNFs), Figure 3 (e) (Si) -Pitch-carbon composite (SiO x -Pitch-CNFs) having a PAN to pitch ratio of 5: 5 and FIG. 3 (f) (Si) -Pitch (Coal tar pitch) -carbon composite (SiO x -Pitch-CNFs).
FIG. 4 is a graph showing a result of performing a thermal analysis to confirm the silicon (Si) residual content of the silicon-pitch-carbon nanofiber (SiO x -Pitch-CNFs) composite according to the present invention.
FIG. 5 is a graph showing the results of an analysis of the capacity of a silicon-pitch-carbon nanofiber (SiO x -Pitch-CNFs) composite according to the present invention for charging and discharging for electrochemical evaluation:
FIG. 5 (a) is a graph showing the relationship between the charge of the first cycle in the CC / CV mode (constant current mode = 0.05 C, constant voltage mode = 0.01 C) FIG. 5 (b) is a graph showing the initial charge / discharge voltage profile at 0.05 C in the mode of FIG. The results are shown in Fig.
FIG. 6 is a graph showing a result of an analysis of capacitance according to a change in current density for an electrochemical evaluation of a silicon-pitch-carbon nanofiber (SiO x -Pitch-CNFs) composite according to the present invention.
7 is a graph showing a result of performing AC impedance analysis to analyze the surface resistance of the silicon-pitch-carbon nanofiber (SiO x -Pitch-CNFs) composite according to the present invention.

이하, 본 발명을 상세하게 설명한다. 본 발명을 설명함에 있어서 관련된 공지 구성 또는 기능에 대한 상세한 설명은 생략할 수 있다.Hereinafter, the present invention will be described in detail. In the following description of the present invention, a detailed description of known configurations and functions will be omitted.

본 명세서 및 특허청구범위에 사용된 용어나 단어는 통상적이거나 사전적 의미로 한정되어 해석되지 아니하며, 본 발명의 기술적 사항에 부합하는 의미와 개념으로 해석되어야 한다.The terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary meanings and should be construed in accordance with the technical meanings and concepts of the present invention.

본 명세서에 기재된 실시예와 도면에 도시된 구성은 본 발명의 바람직한 실시예이며, 본 발명의 기술적 사상을 모두 대변하는 것이 아니므로, 본 출원 시점에서 이들을 대체할 수 있는 다양한 균등물과 변형예들이 있을 수 있다.The embodiments described in the present specification and the configurations shown in the drawings are preferred embodiments of the present invention and are not intended to represent all of the technical ideas of the present invention and thus various equivalents and modifications Can be.

본 발명은 고분자의 일부를 콜타르 피치(Coal tar Pitch)로 대체하여 가격 경쟁력이 우수하며 전자 전도도가 향상되어 보다 개선된 전기화학 특성을 갖는 리튬이차전지용 음극활물질인 실리콘(Si)-피치(Coal tar Pitch)-카본 나노섬유(SiOx-Pitch-CNFs) 복합체를 제공한다.The present invention relates to a negative electrode active material for a lithium secondary battery, which is superior in price competitiveness and has improved electronic conductivity by replacing a part of polymer with a coal tar pitch, Pitch-carbon nanofiber (SiO x -Pitch-CNFs) composite.

구체적으로, 본 발명에 따른 실리콘(Si)-피치(Coal tar Pitch)-카본 나노섬유(SiOx-Pitch-CNFs) 복합체는 탄소 나노 섬유; 피치(Coal tar Pitch) 입자; 및 실리콘(Si) 입자;를 포함하고, 피치 입자와 실리콘 입자가 탄소 나노 섬유에 균일하게 분산되어 섬유 속에 박혀 있는(encapsulated) 구조를 가질 수 있다.Specifically, the silicon (Si) -Pitch-carbon nanofiber (SiO x -Pitch-CNFs) composite according to the present invention is a carbon nanofiber; Coal tar pitch particles; And silicon (Si) particles, wherein the pitch particles and the silicon particles are uniformly dispersed in the carbon nanofibers and encapsulated in the fibers.

상기 복합체는 피치와 고분자가 6:4 내지 4:6의 중량비로 혼합되어 있는 것이 바람직하고, 5:5의 중량비로 혼합되어 있는 것이 더욱 바람직하다.It is preferable that the pitch and the polymer are mixed in a weight ratio of 6: 4 to 4: 6, more preferably 5: 5.

상기 고분자는 폴리아크릴로니트릴(Polyaconitile, PAN), 폴리비닐아세테이트(PVAc), 폴리비닐피롤리돈(PVP), 폴리비닐알콜(PVA), 폴리에틸렌 옥사이드(PEO), 폴리메틸메타아크릴레이트(PMMA), 폴리아크릴산(PAA), 폴리카보네이트(PC), 폴리프닐렌이소프탈라마이드(poly(m)-phenylene isophthalamide, PMIA), 폴리에틸아민(PEI), 폴리에틸렌 테레프탈레이트(PET), 폴리트리메틸렌 테트라프탈레이트(PTT), 폴리부틸렌 테트라프탈레이트(PBT), 폴리설폰(PSF), 폴리에테레테르케톤(polyetheretherketone, PEEK), 폴리스티렌(PS), 폴리비닐리덴플로라이드(PVDF), 폴리우레탄, 폴리비닐 부티랄레신(poly-vinyl butyral resin, PVB), 폴리비닐에스터(PVE), 폴리페로세실디틸실란(polyferrocenyldimethylsilane, PFDMS), 폴리이미드, 폴리피롤(poly-pyrrole-2,5-diyl(p-nitrobenylidene), PPy), 폴리옥시메틸렌(POM), 폴리에틸렌이민(polyethyleneimine, PEI), 폴리아크릴아민(PAM), 폴리에틸렌글리콜(PEG), 폴리락타이드(polylactides, PLLA/PDLA), 폴리카프로락톤(PCL), 폴리글리콜산(PGA), 폴리베타하이드록시알카노아트(poly-β-hydroxyalkanoates, PHA), 폴리부틸렌 써시네이트(poly-butylene succinate, PBS), 폴리에티르 우레탄 우레아(poly-ether urethane urea, PEUU) 및 폴리비닐클로라이드(PVC)로 구성된 군으로부터 선택된 어느 하나 또는 둘 이상의 혼합물인 것이 바람직하고, 폴리아크릴로니트릴(Polyaconitile, PAN)인 것이 더욱 바람직하다.The polymer may be selected from the group consisting of polyacrylonitrile (PAN), polyvinyl acetate (PVAc), polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), polyethylene oxide (PEO), polymethylmethacrylate , Polyacrylic acid (PAA), polycarbonate (PC), polyphenylene isophthalamide (PMIA), polyethylamine (PEI), polyethylene terephthalate (PET), polytrimethylene tetra (PTFE), polybutylene terephthalate (PBT), polysulfone (PSF), polyetheretherketone (PEEK), polystyrene (PS), polyvinylidene fluoride Polyvinyl butyral resin (PVB), polyvinyl ester (PVE), polyferrocenyldimethylsilane (PFDMS), polyimide, poly-pyrrole-2,5-diyl (p-nitrobenylidene) , PPy), polyoxymethylene (POM), polyethyleneimine (polyethyleneimine, (PEI), polyacrylamines (PAM), polyethylene glycols (PEG), polylactides (PLLA / PDLA), polycaprolactone (PCL), polyglycolic acid (PGA), polybetahydroxyalkanoat (PEA) and polyvinyl chloride (PVC), wherein the polymer is selected from the group consisting of poly (? -hydroxyalkanoates, PHA), poly-butylene succinate (PBS), polyether urethaneurea Or a mixture of two or more thereof, and more preferably polyacrylonitrile (PAN).

또한, 실리콘-피치-카본 나노섬유(SiOx-Pitch-CNFs) 복합체를 포함하는 리튬이차전지용 음극활물질을 제공한다.Further, there is provided a negative active material for a lithium secondary battery comprising a silicon-pitch-carbon nanofiber (SiO x -Pitch-CNFs) complex.

또한, 음극활물질을 포함하는 리튬이차전지를 제공한다.Further, a lithium secondary battery including a negative electrode active material is provided.

또한, 본 발명은 상기 본 발명에 따른 실리콘-피치-카본 나노섬유(SiOx-Pitch-CNFs) 복합체를 제조하는 방법을 제공한다.The present invention also provides a method for producing the silicon-pitch-carbon nanofiber (SiO x -Pitch-CNFs) complex according to the present invention.

구체적으로, 상기 방법은 피치(Coal tar Pitch)를 분쇄하여 분말화하는 제 1단계; 실리콘 분말과 피치 분말을 고분자를 용해시킨 용액에 균일하게 혼합하는 제 2단계; 혼합 용액을 전기방사하여 나노섬유 혼합물을 제조하는 제 3단계; 및 나노섬유 혼합물을 열처리하여 나노섬유 복합체를 제조하는 제 4단계;를 포함할 수 있다.Specifically, the method comprises: a first step of pulverizing and pulverizing a pitch (Coal tar Pitch); A second step of uniformly mixing the silicon powder and the pitch powder into a solution in which the polymer is dissolved; A third step of electrospinning the mixed solution to produce a nanofiber mixture; And a fourth step of preparing a nanofiber composite by heat-treating the nanofiber mixture.

상기 제 1단계는 분쇄 과정을 통한 피치(Coal tar Pitch)의 입자의 크기를 줄이는 단계이다.The first step is to reduce the particle size of the pitch (Coal tar pitch) through the grinding process.

상기 제 1단계에 있어서, 분쇄는 볼밀(ball mill)을 통하여 수행할 수 있다.In the first step, the pulverization may be carried out through a ball mill.

상기 볼밀은 볼 무게 대비 피치의 무게가 1.2 내지 1.5 중량%이며, 300 내지 700 rpm으로 5 내지 15시간 동안 수행하는 것이 바람직하고, 500 내지 600 rpm으로 10 내지 12시간 동안 수행하는 것이 더욱 바람직하다.The ball mill preferably has a pitch weight of 1.2 to 1.5% by weight relative to the ball weight, and is preferably performed at 300 to 700 rpm for 5 to 15 hours, more preferably at 500 to 600 rpm for 10 to 12 hours.

상기 무게가 상기 범위의 하한을 미달하는 경우 피치의 변형이 발생하여 조대화 등과 같은 문제가 있고, 상기 범위의 상한을 초과하는 경우 입자 크기가 크거나 불균일한 문제가 발생하여 바람직하지 못하다.When the weight is below the lower limit of the above range, deformation of the pitch occurs and there is a problem such as coarsening. If the weight exceeds the upper limit of the above range, the particle size becomes large or uneven.

상기 시간이 상기 범위의 하한을 미달하는 경우 입자 크기가 크거나 불균일한 문제가 있고, 상기 범위의 상한을 초과하는 경우 피치의 변형이 발생하여 조대화 등과 같은 문제가 발생하여 바람직하지 못하다. When the time falls below the lower limit of the above range, there is a problem that the particle size is large or uneven. When the time exceeds the upper limit of the above range, the pitch is deformed to cause problems such as coarsening.

상기 제 2단계는 실리콘 분말과 피치(Coal tar Pitch)분말을 고분자를 용해시킨 용액에 균일하게 혼합하는 단계이다.The second step is a step of uniformly mixing the silicon powder and the pitch (Coal tar pitch) powder into a solution in which the polymer is dissolved.

상기 제2단계에 있어서, 고분자는 폴리아크릴로니트릴(Polyaconitile, PAN), 폴리비닐아세테이트(PVAc), 폴리비닐피롤리돈(PVP), 폴리비닐알콜(PVA), 폴리에틸렌 옥사이드(PEO), 폴리메틸메타아크릴레이트(PMMA), 폴리아크릴산(PAA), 폴리카보네이트(PC), 폴리프닐렌이소프탈라마이드(poly(m)-phenylene isophthalamide, PMIA), 폴리에틸아민(PEI), 폴리에틸렌 테레프탈레이트(PET), 폴리트리메틸렌 테트라프탈레이트(PTT), 폴리부틸렌 테트라프탈레이트(PBT), 폴리설폰(PSF), 폴리에테레테르케톤(polyetheretherketone, PEEK), 폴리스티렌(PS), 폴리비닐리덴플로라이드(PVDF), 폴리우레탄, 폴리비닐 부티랄레신(poly-vinyl butyral resin, PVB), 폴리비닐에스터(PVE), 폴리페로세실디틸실란(polyferrocenyldimethylsilane, PFDMS), 폴리이미드, 폴리피롤(poly-pyrrole-2,5-diyl(p-nitrobenylidene), PPy), 폴리옥시메틸렌(POM), 폴리에틸렌이민(polyethyleneimine, PEI), 폴리아크릴아민(PAM), 폴리에틸렌글리콜(PEG), 폴리락타이드(polylactides, PLLA/PDLA), 폴리카프로락톤(PCL), 폴리글리콜산(PGA), 폴리베타하이드록시알카노아트(poly-β-hydroxyalkanoates, PHA), 폴리부틸렌 써시네이트(poly-butylene succinate, PBS), 폴리에티르 우레탄 우레아(poly-ether urethane urea, PEUU) 및 폴리비닐클로라이드(PVC)로 구성된 군으로부터 선택된 어느 하나 또는 둘 이상의 혼합물인 것이 바람직하다.In the second step, the polymer is selected from the group consisting of polyacrylonitrile (PAN), polyvinyl acetate (PVAc), polyvinyl pyrrolidone (PVP), polyvinyl alcohol (PVA), polyethylene oxide (PMMA), polyacrylic acid (PAA), polycarbonate (PC), polyphenylene isophthalamide (PMIA), polyethylamine (PEI), polyethylene terephthalate (PTFE), polybutylene terephthalate (PBT), polysulfone (PSF), polyetheretherketone (PEEK), polystyrene (PS), polyvinylidene fluoride (PVDF) Polyvinyl butyral resin (PVB), polyvinyl ester (PVE), polyferrocenyldimethylsilane (PFDMS), polyimide, poly-pyrrole-2,5- diyl (p-nitrobenylidene), PPy), polyoxymethylene (POM), polyethylene (PEI), polyacrylamide (PAM), polyethylene glycol (PEG), polylactides (PLLA / PDLA), polycaprolactone (PCL), polyglycolic acid It is composed of poly-β-hydroxyalkanoates (PHA), poly-butylene succinate (PBS), poly-ether urethane urea (PEUU) and polyvinyl chloride Or a mixture of two or more thereof.

상기 제 2단계에 있어서 피치 분말과 고분자의 중량비는 6:4 내지 4:6인 것이 바람직하고, 5:5인 것이 더욱 바람직하다.In the second step, the weight ratio of the pitch powder and the polymer is preferably 6: 4 to 4: 6, more preferably 5: 5.

본 발명의 실시예에서는 피치 분말과 PAN의 중량비를 다양하게 하여 전지의 용량, 수명, 율속특성 및 표면저항을 종합적으로 분석한 결과, PAN : 피치의 최적비율이 5:5이 바람직함을 확인하였다.In the embodiment of the present invention, the capacity, life time, rate characteristics and surface resistance of the battery were variously analyzed by varying the weight ratio of the pitch powder and the PAN, and it was confirmed that the optimal ratio of PAN: pitch was preferably 5: 5 .

상기 피치 분말과 고분자의 중량비에서 상기 피치 분말이 상기 범위의 하한을 미달하는 경우 전기전도성이 낮아 전지의 출력 특성이 낮아지게 되는 등의 문제가 있고, 상기 범위의 상한을 초과하는 경우 나노섬유의 균일성이 낮은 문제가 발생하여 바람직하지 못하다.When the pitch powder is below the lower limit of the above range in terms of the weight ratio of the pitch powder and the polymer, there is a problem that the electric conductivity is low and the output characteristics of the battery are lowered. When the upper limit of the above range is exceeded, It is not preferable because the problem is low.

상기 제 2단계에 있어서 실리콘 분말과 고분자의 중량비는 1:9 내지 3:7인 것이 바람직하며, 2:8인 것이 더욱 바람직하다.In the second step, the weight ratio of the silicon powder to the polymer is preferably 1: 9 to 3: 7, more preferably 2: 8.

상기 실리콘 분말과 고분자의 중량비에서 상기 실리콘 분말이 상기 범위의 하한을 미달하는 경우 에너지 밀도가 낮아지게 되는 등의 문제가 있고, 상기 범위의 상한을 초과하는 경우 부피팽창을 억제하지 못해 수명특성이 급격하게 감소하는 문제가 발생하여 바람직하지 못하다.There is a problem that the energy density is lowered when the silicon powder falls below the lower limit of the range in the weight ratio of the silicon powder and the polymer. When the upper limit of the above range is exceeded, the volume expansion can not be suppressed, And there is a problem that it is not preferable.

상기 제 2단계에 있어서, 상기 용매는 디메틸포름아마이드(dimethylformamide, DMF), 디메틸아세트아마이드(dimethylacetamide, DMAc), 아세톤, 테트라하이드로퓨란, 물, 아세트산, 헥사플루오로이소프로판올(Hexafluoroisopropanol), 메탄올, 에탄올, 프로판올, 클로로포름, 디클로로메탄, 테트라파이드로퓨란(tetrahydrofuran), 포름산, 아세트산, 트리플루오로아세트산(trifluoroacetic acid), 이소프로판올(isopropanol) 및 톨루엔으로 구성된 군으로부터 선택된 어느 하나 또는 둘 이상의 혼합물인 것이 바람직하다.In the second step, the solvent is selected from the group consisting of dimethylformamide (DMF), dimethylacetamide (DMAc), acetone, tetrahydrofuran, water, acetic acid, hexafluoroisopropanol, methanol, ethanol, It is preferably one or a mixture of two or more selected from the group consisting of propanol, chloroform, dichloromethane, tetrahydrofuran, formic acid, acetic acid, trifluoroacetic acid, isopropanol and toluene.

상기 제 3단계는 상기 혼합 용액을 사용하여 전기방사를 진행하는 단계이다.In the third step, electrospinning is performed using the mixed solution.

상기 제 3단계에 있어서, 상기 전기방사는 용액을 5 kV내지 15 kV의 양(+) 전압을 가한 금속 바늘(27-gauge 내지 19-gauge)을 사용하여 분당 5 ㎕ 내지 100 ㎕의 속도로 방사하는 것이 바람직하며, 8.5 kV내지 15 kV의 양(+) 전압을 가한 금속 바늘(23-gauge)을 사용하는 것이 가장 바람직하다.In the third step, the electrospinning is performed by irradiating the solution with a metal needle (27-gauge to 19-gauge) applied with a positive (+) voltage of 5 kV to 15 kV at a rate of 5 μl to 100 μl per minute And it is most preferable to use a metal needle (23-gauge) with a positive voltage of 8.5 kV to 15 kV.

상기 전압이 상기 범위의 하한을 미달하는 경우 전기장이 약하게 발생해서 나노섬유가 제조되지 않는 문제 혹은 용매가 완전히 증발되지 않는 등의 문제가 있고, 상기 범위의 상한을 초과하는 경우 나노섬유가 너무 얇거나 끊기는 현상이 발생하여 균일성이 낮아지게 되는 문제가 발생하여 바람직하지 못하다.If the voltage is below the lower limit of the above range, there is a problem that the electric field is weak and the nanofiber is not produced or the solvent is not evaporated completely. If the voltage is above the upper limit of the range, the nanofiber is too thin There is a problem in that the uniformity is lowered due to the occurrence of the breaking phenomenon.

상기 속도가 상기 범위의 하한을 미달하는 경우 나노섬유가 끊어지거나 균일성이 낮아지게 되는 등의 문제가 있고, 상기 범위의 상한을 초과하는 경우 나노섬유가 두꺼워지거나 구형태의 복합체가 제조되어 균일성이 낮아지게 되는 문제가 발생하여 바람직하지 못하다. When the speed is below the lower limit of the above range, there is a problem that the nanofibers are broken or the uniformity is lowered. When the upper limit of the above range is exceeded, the nanofibers are thickened or spherical complexes are produced, Is lowered, which is undesirable.

상기 금속바늘 크기가 상기 범위의 하한을 미달하는 경우 바늘구멍이 막혀 전기방사가 되지 않는 등의 문제가 있고, 상기 범위의 상한을 초과하는 경우 나노섬유의 두께가 두껍거나 용매가 증발되지 않는 문제가 발생하여 바람직하지 못하다.If the size of the metal needle is below the lower limit of the above range, there is a problem that the needle hole is clogged and electrospinning does not occur, and when the upper limit of the range is exceeded, the problem that the thickness of the nanofiber is thick or the solvent is not evaporated Which is undesirable.

상기 제 4단계는 상기 혼합물을 열처리 하는 단계이다.The fourth step is a step of heat-treating the mixture.

상기 제 4단계에 있어서, 상기 열처리는 200 ℃ 내지 1000 ℃의 온도 및 불활성 분위기에서 이루어지는 것이 바람직하다.In the fourth step, the heat treatment is preferably performed at a temperature of 200 ° C to 1000 ° C and in an inert atmosphere.

상기 열처리는 공기 분위기에서 250 내지 300 ℃, 3 내지 8시간 동안 열처리를 진행한 후, 불활성 분위기 하에서 800 내지 1000 ℃, 30분 내지 2시간 동안 열처리하는 것이 바람직하며, 공기 분위기에서 280 내지 300 ℃, 5 내지 6시간 동안 열처리를 진행한 후, 불활성 분위기 하에서 900 내지 1000 ℃, 1 내지 2시간 동안 열처리하는 것이 더욱 바람직하다.The heat treatment is preferably carried out in an air atmosphere at 250 to 300 ° C for 3 to 8 hours and then at 800 to 1000 ° C for 30 minutes to 2 hours under an inert atmosphere. It is more preferable to perform heat treatment for 5 to 6 hours and then heat treatment at 900 to 1000 ° C for 1 to 2 hours in an inert atmosphere.

상기 온도가 상기 범위의 하한을 미달하는 경우 고분자의 카본화가 완벽하게 이뤄지지 않는 등의 문제가 있고, 상기 범위의 상한을 초과하는 경우 실리콘이 산화될 수 있는 문제와 카본의 증발로 나노섬유가 얇아지게 되는 문제가 발생하여 바람직하지 못하다.When the temperature is below the lower limit of the above range, there is a problem that the carbonization of the polymer is not completely performed. In the case where the upper limit of the above range is exceeded, silicon may be oxidized and carbon nanofiber may be thinned So that it is not preferable.

상기 시간이 상기 범위의 하한을 미달하는 경우 고분자의 카본화가 완벽하게 이뤄지지 않는 등의 문제가 있고, 상기 범위의 상한을 초과하는 경우 실리콘이 산화될 수 있는 문제와 카본의 증발로 나노섬유가 얇아지게 되는 문제가 발생하여 바람직하지 못하다. When the time is less than the lower limit of the above range, there is a problem that the carbonization of the polymer is not completely performed. In the case where the upper limit of the above range is exceeded, silicon may be oxidized and the nanofiber may be thinned So that it is not preferable.

상기 불활성 분위기의 기체는 아르곤(Ar), 질소(N2), 헬륨(He) 및 네온(Ne)으로 이루어진 군에서 선택된 1종인 것이 바람직하고, 아르곤(Ar)인 것이 더욱 바람직하다.The gas in the inert atmosphere is preferably one selected from the group consisting of argon (Ar), nitrogen (N 2 ), helium (He) and neon (Ne), and more preferably argon (Ar).

또한, 본 발명은 상기 본 발명에 따른 제조 방법으로 제조된, 실리콘-피치-카본 나노섬유(SiOx-Pitch-CNFs) 복합체를 제공한다.In addition, the present invention provides a silicon-pitch-carbon nanofiber (SiO x -Pitch-CNFs) composite produced by the manufacturing method according to the present invention.

또한, 본 발명은 상기 본 발명에 따른 제조 방법으로 제조된 실리콘-피치-카본 나노섬유(SiOx-Pitch-CNFs) 복합체를 포함하는 리튬이차전지용 음극활물질을 제공한다.The present invention also provides a negative electrode active material for a lithium secondary battery comprising the silicon-pitch-carbon nanofiber (SiO x -Pitch-CNFs) composite produced by the production method according to the present invention.

또한, 본 발명은 상기 본 발명에 따른 제조 방법으로 제조된 실리콘-피치-카본 나노섬유(SiOx-Pitch-CNFs) 복합체를 음극활물질로 포함하는 리튬이차전지를 제공한다.Also, the present invention provides a lithium secondary battery comprising the silicon-pitch-carbon nanofiber (SiO x -Pitch-CNFs) composite prepared by the manufacturing method according to the present invention as a negative electrode active material.

이하, 본 발명을 실시예 및 실험예에 의해 상세히 설명한다. Hereinafter, the present invention will be described in detail with reference to Examples and Experimental Examples.

단, 하기 실시예 및 실험예는 본 발명을 예시하는 것일 뿐, 본 발명의 내용이 하기 실시예 및 실험예에 한정되는 것은 아니다.However, the following Examples and Experimental Examples are merely illustrative of the present invention, and the present invention is not limited to the following Examples and Experimental Examples.

<< 실시예Example 1> 실리콘( 1> silicon ( SiSi )-피치(Coal tar Pitch)-카본 복합체() - Coat tar pitch - Carbon composite ( SiOSiO xx -Pitch--Pitch- CNFsCNFs )의 제조)

본 발명은 나노섬유 형태의 실리콘(Si)-피치(Coal tar Pitch)-카본 복합체 제조에 관한 것으로서, 분쇄 과정(Ball milling)을 통한 피치(Coal tar Pitch)의 입자의 크기를 줄이는 단계, 실리콘 분말과 피치(Coal tar Pitch) 분말을 고분자를 용해시킨 용액에 균일하게 혼합하는 단계, 상기 혼합 용액을 사용하여 전기방사를 진행하는 단계, 상기 혼합물을 열처리하는 단계를 포함한다.The present invention relates to a method of manufacturing a nanofiber silicon (Si) -Pitch (Coar tar Pitch) -carbon composite, comprising the steps of reducing the particle size of the pitch by means of ball milling, And a coar tar pitch powder in a solution in which the polymer is dissolved, conducting electrospinning using the mixed solution, and heat-treating the mixture.

구체적으로, (A) 분쇄 과정은 볼밀(ball mill)을 통하여 진행하였으며, 이때 강철(Steel) 소재로 된 볼을 사용하였다. 이때 사용한 볼 무게(200 g-250 g) 대비 피치(Coal tar Pitch)의 무게(3 g) 비율은 약 1.2 %에서 1.5 %이며, 500 rpm으로 10시간 동안 상기 과정을 진행하여 입자의 크기가 감소된 피치(Coal tar Pitch)를 얻었다.Specifically, (A) the grinding process was carried out through a ball mill, and a steel ball was used. The ratio of the weight (3 g) of the coar tar pitch to the ball weight (200 g-250 g) used was about 1.2% to 1.5%, and the process was performed at 500 rpm for 10 hours, (Coal tar pitch) was obtained.

(B) 상기 고분자 물질은 폴리아크릴로니트릴(Polyaconitile, PAN)을 사용하였으며, 혼합용액 제조를 위한 용매로는 디메틸포름아마이드 (Dimethylformamide, DMF)를 사용하였다. 이때 폴리아크릴로니트릴(Polyaconitile, PAN)과 디메틸포름아마이드(Dimethylformamide, DMF)의 질량비를 11:89로 하여 60 ℃의 온도로 가열해 용해시켰다. 이 혼합용액에 분쇄과정을 거친 피치(Coal tar Pitch)를 넣고, 교반(stirring)하였다. 이때, 폴리아크릴로니트릴과 피치(Coal tar Pitch)의 첨가 비율 (PAN: Pitch=4:6, 5:5, 6:4)을 조절하여 혼합용액을 제조하였다. 상기 제조된 혼합용액에 실리콘(Si) 분말을 폴리아크릴로니트릴 대비 2:8 비율로 넣고 교반하여 균질한 혼합용액을 얻었다. (B) Polyacrylonitrile (PAN) was used as the polymer material, and dimethylformamide (DMF) was used as a solvent for preparing the mixed solution. At this time, the mixture was heated to a temperature of 60 캜 at a mass ratio of polyacrylonitrile (PAN) and dimethylformamide (DMF) of 11:89 and dissolved. The mixed solution was pulverized to a pitch (Coal tar pitch), and stirred. At this time, a mixed solution was prepared by controlling the addition ratio (PAN: Pitch = 4: 6, 5: 5, 6: 4) of polyacrylonitrile and a coar tar pitch. Silicon (Si) powder was added to the prepared mixed solution at a ratio of 2: 8 to polyacrylonitrile and stirred to obtain a homogeneous mixed solution.

(C) 상기 제조된 혼합용액을 사용하여 전기방사장치의 공급기를 통하여 공급하고, 이를 방사노즐을 통하여 방사하였다. 방사할 때 8.5 kV/cm 이상의 양(+) 전압을 인가하였다. 방사된 섬유는 방사노즐보다 상대적으로 음(-) 전압을 띤 수집기에 수집하여 일차원(1D)구조를 갖는 나노섬유 복합체를 얻었다.(C) The prepared mixed solution was supplied through a feeder of an electrospinning apparatus and radiated through a spinning nozzle. A positive (+) voltage of 8.5 kV / cm or more was applied when irradiated. The irradiated fibers were collected in a collector with a negative voltage relative to the spinning nozzle to obtain a one-dimensional (1D) nanofiber composite.

전기방사법에 의해 일차원 구조의 나노섬유 혼합물을 제조 후, After preparing a one-dimensional nanofiber mixture by electrospinning,

(D) 상기 제조된 나노 섬유형 복합체를 공기 분위기에서 280 ℃, 5시간 동안 열처리를 진행한 후, 불활성 분위기(Ar) 하에서 900 ℃, 1시간 동안 열처리하여 본 발명의 일차원(1D)의 나노섬유구조 실리콘(Si)-피치(Coal tar Pitch)-카본 복합체(SiOx-Pitch-CNFs)를 완성하였다.(D) The nanofiber-type composite prepared above was heat-treated at 280 ° C for 5 hours in an air atmosphere and then heat-treated at 900 ° C for 1 hour under an inert atmosphere (Ar) to obtain a one-dimensional (1D) Structural Silicon (Si) -Pitch (Coar tar Pitch) -Carbon Composite (SiO x -Pitch-CNFs) was completed.

<< 비교예Comparative Example 1> 피치를 도입하지 않은 실리콘-카본 복합체( 1 > pitch-free silicon-carbon composite ( SiOSiO xx -- CNFsCNFs )의 제조)

앞서 제조한 <실시예 1>과의 비교를 위하여 피치(Coal tar Pitch)를 도입하지 않는 실리콘(Si)-PAN CNFs 복합체를 공기분위기에서 280 ℃, 5시간, 불활성 분위기 (Ar)에서 900 ℃, 1시간 동안 열처리하여 일차원 섬유구조 실리콘(Si)-카본 복합체(SiOx-CNFs)를 제조하였다.(Si) -PAN CNFs composite without the introduction of a pitch (coal tar pitch) in an air atmosphere at 280 DEG C for 5 hours, in an inert atmosphere (Ar) at 900 DEG C, (SiC) -carbon composites (SiO x -CNFs) were prepared by heat treatment for 1 hour.

<< 실험예Experimental Example 1> X선 회절 분석( 1> X-ray diffraction analysis ( XRDXRD )을 통한 구조 분석Structural analysis through

상기 <실시예 1>에서 제조한 일차원(1D) 나노섬유 구조를 갖는 실리콘(Si)-피치(Coal tar Pitch)-카본 복합체의 구조를 분석하기 위하여, <비교예 1>과 함께 X선 회절 분석을 하여 도 1에 나타내었다.In order to analyze the structure of the silicon (Si) -Pitch (Coar tar Pitch) -carbon composite having a one-dimensional (1D) nanofiber structure prepared in Example 1 above, X-ray diffraction analysis As shown in Fig.

구체적으로, X선 회절 분석은 Rigaku사의 Ultima IV 분석기를 이용하였으며, 0.1 g의 시료를 사용하여 측정 속도(scan rate) 4 o/min, 측정 범위(scan range) 5-60 o, 측정 단계(scan step) 0.02 o, 전압 40 kV, 전류 30 mA의 조건으로 수행하였다.Specifically, X-ray diffraction analysis was performed using a Rigaku Ultima IV analyzer. The measurement was performed using a 0.1 g sample at a scan rate of 4 o / min, a scan range of 5-60 o , step was 0.02 o , voltage was 40 kV, and current was 30 mA.

도 1에서 보는 바와 같이, <비교예 1>과 <실시예 1>을 비교하였을 때, 피치(Coal tar Pitch)가 도입되어 그 함량이 증가함에 따라 흑연의 (002)면에 해당하는 25 o 부근의 특정적인 피크 강도(peak intensity)가 증가하였다. 이는 피치(Coal tar Pitch)를 도입함에 따라 결정성이 높은 카본(Graphitic carbon)의 함량이 증가하는 것을 알 수 있다.As shown in FIG. 1, when Comparative Example 1 and Example 1 were compared with each other, a pitch (Coal tar pitch) was introduced to increase the content of graphite to about 25 o Specific peak intensities were increased. It can be seen that the content of graphitic carbon increases with the introduction of pitch (coal tar pitch).

<< 실험예Experimental Example 2> 라만 분광법(Raman spectroscopy)을 통한 구조 분석 2> Structural analysis by Raman spectroscopy

상기 <실시예 1>에서 제조한 실리콘(Si)-피치(Coal tar Pitch)-카본 복합체(SiOx-Pitch-CNFs) 복합체의 표면 구조를 분석하기 위하여, <비교예 1>과 함께 라만 분광법을 이용한 분석을 진행하여 도 2에 나타냈다. In order to analyze the surface structure of the silicon (Si) -Pitch (Co-tar Pitch) -carbon composite (SiO x -Pitch-CNFs) composite prepared in Example 1, Raman spectroscopy The analysis used is shown in Fig.

구체적으로, 라만 분광법은 0.1 g을 펠릿(pellet)으로 제조하여, 라만분광기 MonoRa 750i/ELT10000를 이용하여 488 nm의 아르곤 레이저(Ar laser), 1000-1800 cm-1 의 분석범위에서 라만 분광법을 수행하였다.Specifically, 0.1 g of the Raman spectroscopy was prepared using a pellet and subjected to a 488 nm argon laser (Ar laser) using a Raman spectroscope MonoRa 750i / ELT10000, and Raman spectroscopy at an analysis range of 1000-1800 cm -1 Respectively.

도 2에서 보는 바와 같이, <실시예 1> 및 <비교예 1> 모두 1360 cm- 1와 1580 cm-1 부근의 디 밴드(D band)와 지 밴드(G band)를 확인하였다. <비교예 1>에 비하여 <실시예 1>에서 PAN: Pitch 비율별로(4:6, 5:5, 6:4) 제조한 실리콘(Si)-피치(Coal tar Pitch)-카본 복합체(SiOx-Pitch-CNFs)의 ID/IG 비(ratio)가 감소하는 것으로 확인하였으며, 이러한 경향은 피치(Coal tar Pitch)의 함량이 증가할수록 커지는 것을 확인하였다. 이러한 결과로부터 피치(Coal tar Pitch)의 첨가량이 증가할수록 결정성이 높은 카본(Graphitic carbon)의 양이 증가함을 확인하였다.It was confirmed in the vicinity of the di-band 1 and 1580 cm -1 (D band) and the band support (G band) - As shown in FIG. 2, <Example 1> and <COMPARATIVE EXAMPLE 1> both 1360 cm. (Si) -Pitch (Coar tar Pitch) -carbon composite (SiO x (1)) prepared in Example 1 according to PAN: pitch ratio (4: 6, 5: 5, 6: 4) It was determined that the I D / I G ratio (ratio) of -Pitch-CNFs) decreases, this trend was confirmed to be greater the more the amount of the pitch (pitch Coal tar) increases. From these results, it was confirmed that the amount of carbon (graphitic carbon) with high crystallinity was increased as the amount of pitch (Coar tar Pitch) was increased.

<< 실험예Experimental Example 3> 주사전자현미경(Scanning electron microscope;  3> Scanning electron microscope; SEMSEM )을 통한 형태 분석)

상기 <실시예 1>에서 PAN과 Pitch 비율별로(4:6, 5:5, 6:4) 제조한 실리콘(Si)-피치(Coal tar Pitch)-카본 복합체(SiOx-Pitch-CNFs)의 형태를 관찰하기 위해 주사현미경 분석 이미지를 도 3에 나타냈다. (Si) -Pitch-carbon composite (SiO x -Pitch-CNFs) prepared by PAN and pitch ratio (4: 6, 5: 5, 6: 4) An image of the scanning microscope analysis is shown in Fig. 3 to observe the morphology.

구체적으로, 주사현미경 분석은 JEOL사의 JSM-6700F 주사현미경을 이용하여 10-30 kV의 조건에서 극소량을 사용하여 분석하였다.Specifically, the scanning microscope analysis was performed using JEOL's JSM-6700F scanning microscope using a very small amount at 10-30 kV.

도 3(a)은 분쇄를 하지 않은 피치(Pitch)로 입자의 크기가 약 2 ㎛-10 ㎛로 불균하며, 일차원(1D) 섬유의 두께보다 크기 때문에 균일한 구조 구현에 어려움이 있다. 따라서 분쇄과정을 거쳐 약 200 nm-1 ㎛로 입자의 크기를 감소시켰다(도 3(b)).Fig. 3 (a) is a non-pulverized pitch having a particle size of about 2 占 퐉 to 10 占 퐉, which is larger than the thickness of one-dimensional (1D) fiber, making it difficult to achieve a uniform structure. Thus, the size of the particles was reduced to about 200 nm-1 占 퐉 through pulverization (Fig. 3 (b)).

피치(Coal tar Pitch)를 포함하지 않은 비교예(도 3(c))는 비교적 균일한 두께(1 ㎛)를 가지고 있으며 섬유 형태가 잘 유지되고 있음을 볼 수 있다. 또한 PAN과 Pitch (4:6(도 3(d)), 5:5(도 3(e)), 6:4(도 3(f))) 비율별로 제조된 실시예도 균일한 두께를 가지고 있으며 섬유 형태를 잘 유지하고 있음을 할 수 있다. The comparative example (Fig. 3 (c)) which does not include the pitch (coal tar pitch) has a comparatively uniform thickness (1 탆) and the fiber shape is well maintained. Also, the examples manufactured by the ratio of PAN and Pitch (4: 6 (Fig. 3 (d)), 5: 5 (Fig. 3 (e), and 6: 4 It can be said that the fiber shape is maintained well.

본 발명에 따라 제조한 실리콘(Si)-피치(Coal tar Pitch)-카본 복합체(SiOx-Pitch-CNFs)에서 피치(Coal tar Pitch)입자와 실리콘 입자가 일차원(1D) 섬유형 구조에 균일하게 분산되어 섬유 속에 박혀있음(encapsulated)을 확인하였다.Coat tar pitch particles and silicon particles are uniformly distributed in a one-dimensional (1D) fibrous structure in a silicon (Si) pitch coarse pitch carbon composite (SiO x -Pitch-CNFs) Dispersed and encapsulated in the fibers.

<< 실험예Experimental Example 4> 열 분석법( 4> Thermal Analysis ( ThermogravimetricThermogravimetric Analysis(TG))을 통한 열분해 후 실리콘 잔류 함량 확인 Analysis (TG)) to determine silicon residue after pyrolysis

본 발명에서 제조된 PAN:Pitch 비율(6:4, 5:5, 4:6)에 따른 실리콘(Si)-피치(Coal tar Pitch)-카본 복합체(SiOx-Pitch-CNFs)의 열분해 후 실리콘(Si) 잔류 함량을 관찰하기 위해 열 분석법을 이용하여 도 4에 나타내었다. After pyrolysis of the silicon (Si) -Pitch (Coar tar pitch) -carbon composite (SiO x -Pitch-CNFs) according to the PAN: Pitch ratio (6: 4, 5: 5, 4: 6) (Si) residual content of the silicon oxide film is shown in FIG. 4 by using a thermal analysis method.

구체적으로, 열분석법은 Rigaku사의 TAS-100 열분석 장치를 이용하여 25 ℃에서부터 700 ℃까지 온도를 증가시키면서, 무게 변화를 측정하였다. Specifically, the weight change was measured by increasing the temperature from 25 ° C to 700 ° C using a Rigaku TAS-100 thermal analyzer.

도 4에서 보이는 바와 같이, 피치(Pitch)의 첨가량이 증가함(6:4, 5:5, 4:6)에 따라 단위 무게당 차지하는 카본의 함량(carbon yeild)의 증가로 잔류 실리콘(Si)의 함량이 각각 31 %, 23.3 %, 16 %로 감소하는 경향을 확인할 수 있다.As shown in FIG. 4, residual silicon (Si) is increased due to an increase in the content of carbon per unit weight (carbon yeild) according to an increase in the amount of pitch (6: 4, 5: 5, 4: 6) , Respectively, decreased to 31%, 23.3%, and 16%, respectively.

<< 실험예Experimental Example 5> 전기화학평가를 통한 수명 특성 및  5> Life cycle characteristics through electrochemical evaluation and 율속Rate 특성의 분석 Analysis of characteristics

<5-1> 반쪽 전지의 제조<5-1> Preparation of half cell

본 발명에서 제조된 <실시예 1> 및 <비교예 1>의 음극활물질을 각각 사용해 반쪽 전지를 제조하였다.A half cell was prepared using the negative electrode active materials of Example 1 and Comparative Example 1 prepared in the present invention, respectively.

우선, SiOx-Pitch-CNFs 전극을 제조하였다.First, a SiO x -Pitch-CNFs electrode was prepared.

구체적으로, SiOx-Pitch-CNFs 80 wt%, 아세틸렌 블랙(acetylene black) 10 wt%, 바인더(N-메틸-2-피롤리디논(N-methyl-2-pyrrolidone, NMP)에 용해된 폴리이미드(polyimide, PI)) 10 wt%를 혼합하여 슬러리를 만들어 구리 호일에 코팅하고 코팅된 전극을 110 ℃에서 5시간 건조하였다. 이때, 건조는 진공 건조(10-3 Torr)를 하였고 건조 후 Ar 분위기에서 350 ℃로 1시간 동안 열처리를 하였다. 열처리 완료 후 지름 12 mm인 원 모양으로 전극을 뚫어 SiOx-Pitch-CNFs 전극을 제조하였다.Specifically, a polyimide solution in which 80 wt% of SiO x -Pitch-CNFs, 10 wt% of acetylene black, and a binder (N-methyl-2-pyrrolidone, (PI)) were mixed to prepare a slurry. The slurry was coated on a copper foil, and the coated electrode was dried at 110 ° C for 5 hours. At this time, drying was performed by vacuum drying (10 -3 Torr), and after drying, heat treatment was performed at 350 ° C for 1 hour in an Ar atmosphere. After the completion of the heat treatment, the electrode was drilled in a circular shape with a diameter of 12 mm to prepare an SiO x -Pitch-CNFs electrode.

그런 다음, 반쪽전지를 제조하였다.Then, a half-cell was manufactured.

구체적으로, Ar 분위기의 글러브 박스 안에서 CR2016 코인 타입(coin-type)의 셀(cell)에 작업전극(SiOx-Pitch-CNFs), 분리막(Polypropylene, PP), 상대전극(Li 금속)을 순서대로 쌓고 탄산에틸렌(ethylene carbonate, EC)와 탄산디에틸(diethyl carbonate, DEC)가 부피비 1:1로 된 용매에 리튬염(LiPF6)을 1.3 M, 리튬염 중량비 대비 FEC 첨가제를 5 % 녹인 전해액을 넣고 조립하여 반쪽전지를 제조하였다.Specifically, a working electrode (SiO x -Pitch-CNFs), a polypropylene (PP) electrode and a counter electrode (Li metal) were sequentially placed in a coin-type cell of CR2016 in an Ar atmosphere glove box (LiPF 6 ) in an amount of 1: 1 by volume of ethylene carbonate (EC) and diethyl carbonate (DEC) in a volume ratio of 1.3 M and an electrolytic solution in which FEC additive is dissolved in an amount of 5% And assembled to prepare a half-cell.

<5-2> 전기화학평가<5-2> Electrochemical evaluation

상기 제조된 반쪽전지에 대하여 0.01 V내지 1.5 V에서 구동시켰다. 각 활물질에 대해서 첫 사이클의 충전(charge)은 CC/CV 모드로 (CC (constant current)모드 = 0.05 C, CV (constant voltage)모드 = 0.01 C), 방전(discharge)은 CC (constant current)모드로 0.05 C에서 활성화 시킨 초기 충방전 결과(voltage profile)를 도 5(a)에 나타내었다. 또한 첫 사이클 이후의 사이클은 CC (constant current)모드에서 0.2 C로 각각 50사이클(cycle)까지 충방전을 실시하였고, 그 결과를 도 5(b)에 나타내었다. 0.01 V 내지 1.5 V에서 0.2 C, 0.5 C, 1 C, 2 C, 및 5 C로 전류 밀도를 다르게 하여 율속 평가를 실시하였고, 그 결과를 도 6에 나타내었다. The prepared half-cell was driven at 0.01 V to 1.5 V. For each active material, the charge of the first cycle is in the CC / CV mode (constant current mode = 0.05 C, constant voltage mode = 0.01 C) Figure 5 (a) shows the initial charge and discharge voltage profile at 0.05 C, The cycle after the first cycle was charged and discharged at 0.2 C in constant current mode until 50 cycles, and the result is shown in FIG. 5 (b). Rate evaluation was performed by varying the current density from 0.01 V to 1.5 V at 0.2 C, 0.5 C, 1 C, 2 C, and 5 C, and the results are shown in FIG.

도 5(a)을 참조하면, 0.01 V 내지 1.5 V의 첫 사이클 충방전 결과에서 본 발명에 따라 <실시예 1>에서 제조한 PAN:Pitch 비율별(6:4, 5:5, 4:6) 실리콘(Si)-피치(Coal tar Pitch)-카본 복합체(SiOx-Pitch-CNFs)는 <비교예 1>과 같은 산화/환원 반응을 나타내었다. 또한, PAN 대비 피치(Pitch)의 비율이 늘어날수록 낮은 용량을 나타내었다. 이는 도 4에서 열처리 후 나노섬유의 단위 면적당 잔류 카본의 증가로 실리콘(Si)의 양이 줄어들어 나타나는 것을 알 수 있다. Referring to FIG. 5 (a), the results of the first cycle charge and discharge of 0.01 V to 1.5 V show that the PAN: Pitch ratio (6: 4, 5: 5, 4: ) Si (Co-tar Pitch) -carbon composite (SiO x -Pitch-CNFs) exhibited the same oxidation / reduction reaction as in Comparative Example 1. Also, as the ratio of pitch to PAN increased, it showed lower capacity. It can be seen from FIG. 4 that the amount of silicon (Si) decreases due to an increase in residual carbon per unit area of the nanofibers after heat treatment.

도 5(b)를 참조하면, 본 발명에서 제조된 PAN:Pitch 비율(6:4, 5:5, 4:6)에 따른 실리콘(Si)-피치(Coal tar Pitch)-카본 복합체(SiOx-Pitch-CNFs)는 PAN:Pitch의 비율에 따라 각각 76 %, 81 %, 84 %의 용량 유지율을 나타낸다. 또한, <비교예 1>을 음극활물질로 사용하여 제조된 리튬이온 반쪽전지의 유지율은 75 %로 나타난 데에 비해 수명특성이 개선된 것을 확인하였다. 이러한 결과는 구조적으로 안정한 피치가 증가할수록 실리콘의 양이 줄어 방전용량은 낮지만 수명특성은 피치에 의해 개선되는 것을 확인할 수 있다.A Referring to Figure 5 (b), produced by the invention PAN: Pitch ratio (6: 4, 5: 5, 4: 6), silicon (Si) according to-pitch (Coal tar Pitch) - carbonyl complex (SiO x -Pitch-CNFs) show capacity retention rates of 76%, 81% and 84%, respectively, according to the ratio of PAN: Pitch. Also, it was confirmed that the lifetime characteristics of the lithium ion battery produced using Comparative Example 1 as the negative electrode active material were improved to 75%, compared with that of the lithium ion battery. These results show that as the structurally stable pitch increases, the amount of silicon decreases and the discharge capacity decreases, but the lifetime characteristics are improved by the pitch.

도 6을 참조하면, 본 발명에 따라 PAN:Pitch 비율별(6:4, 5:5, 4:6)로 제조한 실리콘(Si)-피치(Coal tar Pitch)-카본 복합체(SiOx-Pitch-CNFs)를 음극활물질로 사용하여 제조된 상기 리튬이온 반쪽전지는 높은 전류밀도인 5 C에서도 0.2 C대비 각각 59.5 %, 82.5 %, 72.3 %의 유지율을 보이고 있다. 또한, 비교예 1을 음극활물질로 사용하여 제조된 리튬이온 반쪽전지는 5 C에서 0.2 C 대비 유지율이 59 %를 나타내는 것을 확인하였다.Referring to FIG. 6, a silicon (Si) -Pitch (Coat tar pitch) -carbon composite (SiO x -Pitch) having a PAN: pitch ratio of 6: 4, 5: 5, -CNFs) as a negative electrode active material, the lithium ion half cell has a maintenance ratio of 59.5%, 82.5%, and 72.3%, respectively, at 0.2C, even at a high current density of 5C. In addition, it was confirmed that the lithium ion battery produced using the negative electrode active material of Comparative Example 1 had a retention ratio of 59% as compared with 0.2C at 5C.

상기 결과로부터 본 발명에 따라 제조된 실리콘(Si)-피치(Coal tar Pitch)-카본 복합체(SiOx-Pitch-CNFs)는 지속적인 충방전에 의한 실리콘의 부피팽창에도 불구하고 우수한 수명특성(cycle retention) 및 율속(kinetic)특성을 나타내는 것을 확인하였다. 또한, 피치(Pitch)의 첨가 비율이 증가함에 따라 단위 무게당 카본의 비율(carbon yield)이 늘어나 용량감소 하지만, 구조적 안정성과 전도성이 우수하여 수명 특성과 율속 특성 향상에 효과적인 것으로 판단된다.From the above results, it can be seen that the silicon (Si) -pitch-carbon composite (SiO x -Pitch-CNFs) prepared according to the present invention has excellent cycle life ) And kinetic characteristics. Also, as the ratio of pitch is increased, the carbon yield per unit weight is increased and the capacity is decreased. However, it is considered to be effective in improving lifetime characteristics and rate characteristics because of excellent structural stability and conductivity.

<< 실험예Experimental Example 6> 교류 임피던스 분석법을 통한 저항 분석 6> Resistance Analysis by AC Impedance Analysis

본 발명에서 제조한 실리콘(Si)-피치(Coal tar Pitch)-카본 복합체(SiOx-Pitch-CNFs)을 사용하여 제조한 리튬이온 반쪽전지의 저항을 확인하기 위하여 교류 임피던스 분석법을 수행하여 그 결과를 도 7에 나타내었다.AC impedance analysis was performed to confirm the resistance of the lithium ion semi-cell fabricated using the silicon (Si) -pitch (Co-tar pitch) -carbon composite (SiO x -Pitch-CNFs) Is shown in Fig.

구체적으로, 제조된 반쪽전지를 이용해 Ivium Technologies사의 Iviumstat 전력분석기를 사용하여 진폭 5 mV, 진동수 0.1~100 kHz의 조건에서 교류 임피던스 분석법을 수행하였다.Specifically, using the Iviumstat power analyzer manufactured by Ivium Technologies, the produced half-cell was subjected to AC impedance analysis under the conditions of an amplitude of 5 mV and a frequency of 0.1 to 100 kHz.

도 7(a)에서 보이는 바와 같이, 충방전을 진행하지 않은 활물질의 표면저항(surface resistance)을 측정한 결과 비교예 1의 활물질에 비하여 PAN:Pitch 비율 별로 제조한 활물질의 표면저항이 감소하는 것을 확인하였다. As shown in FIG. 7 (a), the surface resistance of the active material that did not undergo charging / discharging was measured. As a result, the surface resistance of the active material produced by the ratio of PAN to Pitch was decreased compared to the active material of Comparative Example 1 Respectively.

도 7(b)을 참고하면, 첫 사이클 충방전 완료 후 활물질의 표면저항(surface resistance)을 측정하였을 때 마찬가지로 비교예 1의 활물질 표면저항보다 실시예의 활물질 표면저항이 작은 것을 확인할 수 있었다.  7 (b), when the surface resistance of the active material was measured after completion of charge and discharge for the first cycle, it was confirmed that the surface resistivity of the active material of the Example was smaller than that of the active material of Comparative Example 1.

상기 결과로부터, 실리콘(Si)-카본 복합체(SiOx-CNFs)에 피치(Coal tar Pitch)를 도입함으로써 초기 표면저항 감소 및 충방전시 형성되는 고체 전해질막(SEI film)을 안정화에 기인하는 것을 확인하였다.From the above results, it was found that by introducing a pitch (Coar tar Pitch) into the silicon (Si x -CNFs), the initial surface resistivity was reduced and the solid electrolyte film (SEI film) Respectively.

상기 결과들로부터, 전지의 용량, 수명, 율속특성 및 표면저항을 종합적으로 판단하였을 때 PAN:Pitch의 최적비율은 5:5임을 알 수 있었다. From the above results, it can be seen that the optimum ratio of PAN: Pitch is 5: 5 when the capacity, lifetime, rate characteristics and surface resistance of the battery are comprehensively judged.

이상과 같이, 본 명세서와 도면에는 본 발명의 바람직한 실시예에 대하여 개시하였으며, 비록 특정 용어들이 사용되었으나, 이는 단지 본 발명의 기술 내용을 쉽게 설명하고 발명의 이해를 돕기 위한 일반적인 의미에서 사용된 것이지, 본 발명의 범위를 한정하고자 하는 것은 아니다. As described above, preferred embodiments of the present invention have been disclosed in the present specification and drawings, and although specific terms have been used, they have been used only in a general sense to easily describe the technical contents of the present invention and to facilitate understanding of the invention , And are not intended to limit the scope of the present invention.

여기에 개시된 실시예 외에도 본 발명의 기술적 사상에 바탕을 둔 다른 변형 예들이 실시 가능하다는 것은 본 발명이 속하는 기술 분야에서 통상의 지식을 가진 자에게 자명한 것이다.It is to be understood by those skilled in the art that other modifications based on the technical idea of the present invention are possible in addition to the embodiments disclosed herein.

Claims (18)

탄소 나노 섬유;
피치(Coal tar Pitch) 입자; 및
실리콘(Si) 입자;를 포함하고,
피치 입자와 실리콘 입자가 탄소 나노 섬유에 균일하게 분산되어 섬유 속에 박혀 있는(encapsulated) 것을 특징으로 하는,
실리콘-피치-카본 나노섬유(SiOx-Pitch-CNFs) 복합체.
Carbon nanofibers;
Coal tar pitch particles; And
Silicon (Si) particles,
Characterized in that the pitch particles and the silicon particles are uniformly dispersed in the carbon nanofibers and encapsulated in the fibers.
Silicon-pitch-carbon nanofiber (SiO x -Pitch-CNFs) composite.
제 1항의 실리콘-피치-카본 나노섬유(SiOx-Pitch-CNFs) 복합체를 포함하는 리튬이차전지용 음극활물질.
A negative electrode active material for a lithium secondary battery, comprising the silicon-pitch-carbon nanofiber (SiO x -Pitch-CNFs) composite of claim 1.
제 2항의 음극활물질을 포함하는 리튬이차전지.
A lithium secondary battery comprising the negative electrode active material of claim 2.
피치(Coal tar Pitch)를 분쇄하여 분말화하는 제 1단계;
실리콘 분말과 피치 분말을 고분자를 용해시킨 용액에 균일하게 혼합하는 제 2단계;
혼합 용액을 전기방사하여 나노섬유 혼합물을 제조하는 제 3단계; 및
나노섬유 혼합물을 열처리하여 나노섬유 복합체를 제조하는 제 4단계;를 포함하는,
실리콘-피치-카본 나노섬유(SiOx-Pitch-CNFs) 복합체의 제조 방법.
Pulverizing and pulverizing the pitch (Coal tar Pitch);
A second step of uniformly mixing the silicon powder and the pitch powder into a solution in which the polymer is dissolved;
A third step of electrospinning the mixed solution to produce a nanofiber mixture; And
And a fourth step of preparing a nanofiber composite by heat treating the nanofiber mixture.
Method for manufacturing silicon-pitch-carbon nanofiber (SiO x -Pitch-CNFs) complexes.
제 4항에 있어서,
상기 제 1 단계에 있어서 분쇄는 볼밀(ball mill)을 통하여 수행하는 것을 특징으로 하는 실리콘-피치-카본 나노섬유(SiOx-Pitch-CNFs) 복합체의 제조 방법.
5. The method of claim 4,
Wherein the pulverization is carried out through a ball mill in the first step. &Lt; RTI ID = 0.0 &gt; [ 10] & lt ; / RTI &gt;
제 5항에 있어서,
상기 볼밀은 볼 무게 대비 피치의 무게가 1.2 내지 1.5 중량%로서 300 내지 700 rpm으로 5 내지 15시간 동안 진행하는 것을 특징으로 하는 실리콘-피치-카본 나노섬유(SiOx-Pitch-CNFs) 복합체의 제조 방법.
6. The method of claim 5,
Wherein the ball mill has a pitch weight of 1.2 to 1.5% by weight relative to the ball weight and is run at 300 to 700 rpm for 5 to 15 hours to produce a silicon-pitch-carbon nanofiber (SiO x -Pitch-CNFs) composite Way.
제 4항에 있어서,
상기 제 2단계에 있어서 고분자는 폴리아크릴로니트릴(Polyaconitile, PAN), 폴리비닐아세테이트(PVAc), 폴리비닐피롤리돈(PVP), 폴리비닐알콜(PVA), 폴리에틸렌 옥사이드(PEO), 폴리메틸메타아크릴레이트(PMMA), 폴리아크릴산(PAA), 폴리카보네이트(PC), 폴리프닐렌이소프탈라마이드(poly(m)-phenylene isophthalamide, PMIA), 폴리에틸아민(PEI), 폴리에틸렌 테레프탈레이트(PET), 폴리트리메틸렌 테트라프탈레이트(PTT), 폴리부틸렌 테트라프탈레이트(PBT), 폴리설폰(PSF), 폴리에테레테르케톤(polyetheretherketone, PEEK), 폴리스티렌(PS), 폴리비닐리덴플로라이드(PVDF), 폴리우레탄, 폴리비닐 부티랄레신(poly-vinyl butyral resin, PVB), 폴리비닐에스터(PVE), 폴리페로세실디틸실란(polyferrocenyldimethylsilane, PFDMS), 폴리이미드, 폴리피롤(poly-pyrrole-2,5-diyl(p-nitrobenylidene), PPy), 폴리옥시메틸렌(POM), 폴리에틸렌이민(polyethyleneimine, PEI), 폴리아크릴아민(PAM), 폴리에틸렌글리콜(PEG), 폴리락타이드(polylactides, PLLA/PDLA), 폴리카프로락톤(PCL), 폴리글리콜산(PGA), 폴리베타하이드록시알카노아트(poly-β-hydroxyalkanoates, PHA), 폴리부틸렌 써시네이트(poly-butylene succinate, PBS), 폴리에티르 우레탄 우레아(poly-ether urethane urea, PEUU) 및 폴리비닐클로라이드(PVC)로 구성된 군으로부터 선택된 어느 하나 또는 둘 이상의 혼합물인 것을 특징으로 하는 실리콘-피치-카본 나노섬유(SiOx-Pitch-CNFs) 복합체의 제조 방법.
5. The method of claim 4,
In the second step, the polymer may be selected from the group consisting of polyacrylonitrile (PAN), polyvinyl acetate (PVAc), polyvinyl pyrrolidone (PVP), polyvinyl alcohol (PVA), polyethylene oxide (PMMA), polyacrylic acid (PAA), polycarbonate (PC), poly (m) -phenylene isophthalamide (PMIA), polyethylamine (PEI), polyethylene terephthalate , Polytrimethylene tetraphthalate (PTT), polybutylene tetraphthalate (PBT), polysulfone (PSF), polyetheretherketone (PEEK), polystyrene (PS), polyvinylidene fluoride Polyvinyl butyral resin (PVB), polyvinyl ester (PVE), polyferrocenyldimethylsilane (PFDMS), polyimide, poly-pyrrole (2,5-diyl (p-nitrobenylidene), PPy), polyoxymethylene (POM), polyethylene (PEI), polyacrylamide (PAM), polyethylene glycol (PEG), polylactides (PLLA / PDLA), polycaprolactone (PCL), polyglycolic acid It is composed of poly-β-hydroxyalkanoates (PHA), poly-butylene succinate (PBS), poly-ether urethane urea (PEUU) and polyvinyl chloride (SiO x --Pitch - CNFs) composite according to any one of claims 1 to 3,
제 4항에 있어서,
상기 제 2단계에 있어서 피치 분말과 고분자의 중량비는 6:4 내지 4:6인 것을 특징으로 하는 실리콘-피치-카본 나노섬유(SiOx-Pitch-CNFs) 복합체의 제조 방법.
5. The method of claim 4,
The weight ratio of the pitch powder and polymer in the second step is 6: 4 to 4: silicon, characterized in that the 6-pitch - carbon nano-fiber production method of the (SiO x -Pitch-CNFs) complex.
제 8항에 있어서,
상기 피치 분말과 고분자의 중량비는 5:5인 것을 특징으로 하는 실리콘-피치-카본 나노섬유(SiOx-Pitch-CNFs) 복합체의 제조 방법.
9. The method of claim 8,
Wherein the weight ratio of the pitch powder to the polymer is 5: 5. &Lt; RTI ID = 0.0 &gt; 8. & lt ; / RTI &gt;
제 4항에 있어서,
상기 제 2단계에 있어서 실리콘 분말과 고분자의 중량비는 1:9 내지 3:7인 것을 특징으로 하는 실리콘-피치-카본 나노섬유(SiOx-Pitch-CNFs) 복합체의 제조 방법.
5. The method of claim 4,
The weight ratio of the silicon powder and the polymer in the second step is from 1: 9 to 3: silicon, characterized in that 7 - The method of producing a carbon nanofiber (SiO x -Pitch-CNFs) complex-pitch.
제 4항에 있어서,
상기 제 2단계에 있어서 용매는 디메틸포름아마이드(dimethylformamide, DMF), 디메틸아세트아마이드(dimethylacetamide, DMAc), 아세톤, 테트라하이드로퓨란, 물, 아세트산, 헥사플루오로이소프로판올(Hexafluoroisopropanol), 메탄올, 에탄올, 프로판올, 클로로포름, 디클로로메탄, 테트라파이드로퓨란(tetrahydrofuran), 포름산, 아세트산, 트리플루오로아세트산(trifluoroacetic acid), 이소프로판올(isopropanol) 및 톨루엔으로 구성된 군으로부터 선택된 어느 하나 또는 둘 이상의 혼합물인 것을 특징으로 하는 실리콘-피치-카본 나노섬유(SiOx-Pitch-CNFs) 복합체의 제조 방법.
5. The method of claim 4,
In the second step, the solvent is selected from the group consisting of dimethylformamide (DMF), dimethylacetamide (DMAc), acetone, tetrahydrofuran, water, acetic acid, hexafluoroisopropanol, methanol, ethanol, Is a mixture of one or more selected from the group consisting of chloroform, dichloromethane, tetrahydrofuran, formic acid, acetic acid, trifluoroacetic acid, isopropanol and toluene. Method for producing pitch-carbon nanofiber (SiO x -Pitch-CNFs) complexes.
제 4항에 있어서,
상기 제 3단계에 있어서 상기 전기방사는 용액을 5 kV내지 15 kV의 양(+) 전압을 가한 금속 바늘을 사용하여 분당 5 ㎕ 내지 100 ㎕의 비율로 방사하는 것을 특징으로 하는 실리콘-피치-카본 나노섬유(SiOx-Pitch-CNFs) 복합체의 제조 방법.
5. The method of claim 4,
In the third step, the electrospinning is performed by spitting the solution at a rate of 5 μl to 100 μl per minute using a metal needle with a positive (+) voltage of 5 kV to 15 kV. Method of making nanofibers (SiO x -Pitch-CNFs) complexes.
제 4항에 있어서,
상기 제 4단계에 있어서 열처리는 200℃ 내지 1000℃의 온도 및 불활성 분위기에서 이루어지는 것을 특징으로 하는 실리콘-피치-카본 나노섬유(SiOx-Pitch-CNFs) 복합체의 제조 방법.
5. The method of claim 4,
The method of manufacturing a silicon-pitch-carbon nanofiber (SiO x -Pitch-CNFs) composite according to claim 4, wherein the heat treatment is performed at a temperature of 200 ° C. to 1000 ° C. and in an inert atmosphere.
제 4항에 있어서,
상기 제 4단계에 있어서 열처리는 공기 분위기에서 250 내지 300 ℃, 3 내지 8시간 동안 열처리를 진행한 후, 불활성 분위기 하에서 800 내지 1000 ℃, 30분 내지 2시간 동안 열처리하는 것을 특징으로 하는 실리콘-피치-카본 나노섬유(SiOx-Pitch-CNFs) 복합체의 제조 방법.
5. The method of claim 4,
In the fourth step, the heat treatment is performed in an air atmosphere at 250 to 300 ° C for 3 to 8 hours, and then heat-treated in an inert atmosphere at 800 to 1000 ° C for 30 minutes to 2 hours. - Manufacturing method of carbon nanofiber (SiO x -Pitch-CNFs) composite.
제 14항에 있어서,
상기 불활성 분위기의 기체는 아르곤(Ar), 질소(N2), 헬륨(He) 및 네온(Ne)으로 이루어진 군에서 선택된 1종 이상인 것을 특징으로 하는 실리콘-피치-카본 나노섬유(SiOx-Pitch-CNFs) 복합체의 제조 방법.
15. The method of claim 14,
The gas of the inert atmosphere is argon (Ar), nitrogen (N 2), helium (He) and neon silicon, characterized in that at least one member selected from the group consisting of (Ne) - pitch - carbon nano fiber (SiO x -Pitch -CNFs) complexes.
제 4항 내지 제 15항 중 어느 한 항의 제조 방법을 통해 제조된, 실리콘-피치-카본 나노섬유(SiOx-Pitch-CNFs) 복합체.
15. A silicon-pitch-carbon nanofiber (SiO x -Pitch-CNFs) composite prepared by the method of any one of claims 4 to 15.
제 16항의 실리콘-피치-카본 나노섬유(SiOx-Pitch-CNFs) 복합체를 포함하는 리튬이차전지용 음극활물질.
A negative electrode active material for a lithium secondary battery comprising the silicon-pitch-carbon nanofiber (SiO x -Pitch-CNFs) composite of claim 16.
제 17항의 음극활물질을 포함하는 리튬이차전지.A lithium secondary battery comprising the negative electrode active material of claim 17.
KR1020160025733A 2016-03-03 2016-03-03 Negative electrode active material for lithium ion battery using composite of silicon comprising coal tar pitch and carbon nanofiber, and preparing method thereof KR20170104035A (en)

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Cited By (4)

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CN110656442A (en) * 2019-08-20 2020-01-07 苏州大学 Lithium ion battery diaphragm and preparation method thereof
CN111095626A (en) * 2018-05-24 2020-05-01 株式会社Lg化学 Negative active material for lithium secondary battery and method for preparing same
CN113003579A (en) * 2021-03-23 2021-06-22 内蒙古科技大学 Green method for comprehensive utilization of coal gangue
US11962003B2 (en) 2019-01-21 2024-04-16 Lg Energy Solution, Ltd. Negative electrode active material for lithium secondary battery, and negative electrode and lithium secondary battery including the same

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111095626A (en) * 2018-05-24 2020-05-01 株式会社Lg化学 Negative active material for lithium secondary battery and method for preparing same
CN111095626B (en) * 2018-05-24 2022-06-24 株式会社Lg新能源 Negative active material for lithium secondary battery and method for preparing same
US11962003B2 (en) 2019-01-21 2024-04-16 Lg Energy Solution, Ltd. Negative electrode active material for lithium secondary battery, and negative electrode and lithium secondary battery including the same
CN110656442A (en) * 2019-08-20 2020-01-07 苏州大学 Lithium ion battery diaphragm and preparation method thereof
CN113003579A (en) * 2021-03-23 2021-06-22 内蒙古科技大学 Green method for comprehensive utilization of coal gangue

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