KR20220061593A - Anode Materials for Secondary Batteries and Method Producing the Same - Google Patents

Anode Materials for Secondary Batteries and Method Producing the Same Download PDF

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KR20220061593A
KR20220061593A KR1020200147727A KR20200147727A KR20220061593A KR 20220061593 A KR20220061593 A KR 20220061593A KR 1020200147727 A KR1020200147727 A KR 1020200147727A KR 20200147727 A KR20200147727 A KR 20200147727A KR 20220061593 A KR20220061593 A KR 20220061593A
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graphene
lithium secondary
secondary battery
negative electrode
active material
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Korean (ko)
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박상목
김익규
오승민
김사흠
이윤성
반성호
이지은
엠 야쉬 조쉬
주용락
자마니 소마예
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현대자동차주식회사
기아 주식회사
코넬 유니버시티
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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
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/134—Electrodes based on metals, Si or alloys
    • 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
    • H—ELECTRICITY
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    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/04—Processes of manufacture in general
    • 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
    • H01M4/04—Processes of manufacture in general
    • H01M4/0471—Processes of manufacture in general involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis
    • 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
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • 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
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/139—Processes of manufacture
    • H01M4/1391—Processes of manufacture of electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • 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
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/139—Processes of manufacture
    • H01M4/1395—Processes of manufacture of electrodes based on metals, Si or alloys
    • 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
    • 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
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/483—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides for non-aqueous cells
    • 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
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/621—Binders
    • H01M4/622—Binders being polymers
    • 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
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/624—Electric conductive fillers
    • H01M4/625—Carbon or graphite
    • 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

Abstract

The present invention relates to an anode material for a lithium secondary battery and a manufacturing method thereof capable of improving initial efficiency and an endurance thermal phenomenon by forming a conductive material and improving a ratio with an anode active material. The anode material for a lithium secondary battery according to an embodiment of the present invention includes a main component consisting of a Si-based anode active material and graphene. An average particle diameter (S_d) of the Si-based anode active material is 30 ㎚-1.0 ㎛. A long axis length (G_dL) of the graphene is 30 times or more of the average particle diameter (S_d) of the Si-based anode active material.

Description

리튬 이차전지용 음극소재 및 그 제조방법{Anode Materials for Secondary Batteries and Method Producing the Same}Anode Materials for Secondary Batteries and Method Producing the Same

본 발명은 리튬 이차전지용 음극소재 및 그 제조방법에 관한 것으로서, 더욱 상세하게는 도전재의 형상 및 음극 활물질과의 비율을 개선하여 초기효율 향상 및 내구열화 현상을 개선할 수 있는 리튬 이차전지용 음극소재 및 그 제조방법에 관한 것이다.The present invention relates to a negative electrode material for a lithium secondary battery and a method for manufacturing the same, and more particularly, to an anode material for a lithium secondary battery capable of improving initial efficiency and durability deterioration by improving the shape of a conductive material and a ratio with a negative active material, and It relates to a manufacturing method thereof.

이차전지는 전기 자동차나 전지 전력 저장 시스템 등의 대용량 전력 저장 전지와 휴대 전화, 캠코더, 노트북 등의 휴대 전자기기의 소형의 고 성능 에너지원으로 사용되고 있다. 휴대 전자기기의 소형화와 장시간 연속 사용을 목표로 부품의 경량화와 저 소비 전력화에 대한 연구와 더불어 소형이면서 고 용량을 실현할 수 있는 이차전지가 요구되고 있다.Secondary batteries are used as large-capacity power storage batteries for electric vehicles and battery power storage systems, and as small, high-performance energy sources for portable electronic devices such as mobile phones, camcorders, and notebook computers. With the aim of miniaturization of portable electronic devices and continuous use for a long time, there is a demand for a secondary battery capable of realizing small size and high capacity along with research on weight reduction and low power consumption.

특히, 대표적인 이차전지인 리튬 이차전지는 니켈 망간 전지나 니켈 카드뮴 전지보다 에너지 밀도가 높고 면적당 용량이 크고, 자기 방전율이 낮으며 수명이 길다. 또한, 메모리 효과가 없어서 사용의 편리성과 장수명의 특성을 갖는다.In particular, a lithium secondary battery, which is a typical secondary battery, has a higher energy density, a larger capacity per area, a lower self-discharge rate, and a longer lifespan than a nickel manganese battery or a nickel cadmium battery. In addition, since there is no memory effect, it has the characteristics of convenience of use and long life.

리튬 이차전지는 리튬 이온의 삽입(intercalations) 및 탈리(deintercalation)가 가능한 활물질로 이루어진 양극과 음극 사이에 전해질을 충전시킨 상태에서 리튬 이온이 양극 및 음극에서 삽입/탈리 될 때의 산화와 환원 반응에 의해 전기 에너지가 생산된다.Lithium secondary batteries are designed for oxidation and reduction reactions when lithium ions are inserted/desorbed from the positive and negative electrodes in a state where an electrolyte is charged between the positive electrode and the negative electrode made of an active material capable of intercalation and deintercalation of lithium ions. electrical energy is produced by

이러한 리튬 이차전지는 양극, 전해질, 분리막, 음극 등으로 구성되며, 구성요소 간의 계면 반응을 안정하게 유지하는 것이 전지의 장수명 및 신뢰성 확보를 위해 매우 중요하다.Such a lithium secondary battery is composed of a positive electrode, an electrolyte, a separator, a negative electrode, etc., and maintaining a stable interfacial reaction between the components is very important to ensure a long life and reliability of the battery.

한편, 리튬 이차전지는 통상적으로 양극에는 LiCoO2, LiMn2O4 등과 같이 리튬이 삽입되어 있는 화합물을 사용하고, 음극에는 탄소계, Si계 등의 리튬이 삽입되어 있지 않는 물질을 사용하여 제조되며, 충전시에는 양극에 삽입된 리튬 이온이 전해액을 통해 음극으로 이동하고, 방전시에는 다시 리튬 이온이 음극에서 양극으로 이동하게 된다. On the other hand, lithium secondary batteries are typically manufactured by using a compound in which lithium is inserted, such as LiCoO 2 , LiMn 2 O 4 , etc. for the positive electrode, and using a material in which lithium is not inserted, such as carbon-based or Si-based lithium, for the negative electrode. During charging, lithium ions inserted into the positive electrode move to the negative electrode through the electrolyte, and during discharging, lithium ions move from the negative electrode to the positive electrode again.

특히, Si계 물질은 리튬이온 이차전지용 고용량 음극소재로서 사용되고 있다.In particular, the Si-based material is used as a high-capacity negative electrode material for a lithium ion secondary battery.

하지만, 고용량을 가진 음극소재 임에도 불구하고 초기효율 저하, 내구특성저하 등 고질적인 문제로 10% 내외의 Si계 물질을 흑연과 블랜딩하여 사용하고 있다.However, in spite of being a high-capacity anode material, about 10% of Si-based material is blended with graphite and used due to chronic problems such as reduced initial efficiency and reduced durability.

향후 배터리셀의 추가적인 에너지밀도 향상을 위하여 Si계 물질의 사용량을 증가시키고 나아가 Si계 물질을 주성분으로 사용하는 기술을 개발할 필요가 있다.In order to further improve the energy density of the battery cell in the future, it is necessary to increase the amount of Si-based material and further develop a technology using the Si-based material as a main component.

이에, 본 출원인은 Si계 물질의 크기 및 전기 전도기능을 부여하는 도전재 성분의 종류, 형상, 비율 등의 최적화를 통하여 배터리셀의 초기효율 및 내구특성 등을 개선할 수 있다는 것에 착안하여 본 발명을 완성하였다.Accordingly, the applicant of the present invention focused on the fact that the initial efficiency and durability of the battery cell can be improved by optimizing the size of the Si-based material and the type, shape, ratio, etc. of the conductive material that imparts the electrical conduction function. was completed.

상기의 배경기술로서 설명된 내용은 본 발명에 대한 배경을 이해하기 위한 것일 뿐, 이 기술분야에서 통상의 지식을 가진 자에게 이미 알려진 종래기술에 해당함을 인정하는 것으로 받아들여져서는 안 될 것이다.The content described as the background art above is only for understanding the background of the present invention, and should not be taken as an acknowledgment that it corresponds to the prior art known to those of ordinary skill in the art.

공개특허공보 제10-2020-0025983호 (2020.03.10)Laid-open Patent Publication No. 10-2020-0025983 (2020.03.10)

본 발명은 도전재의 형상 및 음극 활물질과의 비율을 개선하여 내구열화 현상을 개선할 수 있는 리튬 이차전지용 음극소재 및 그 제조방법을 제공한다.The present invention provides a negative electrode material for a lithium secondary battery capable of improving the durability deterioration phenomenon by improving the shape of the conductive material and the ratio with the negative electrode active material, and a method for manufacturing the same.

본 발명의 일 실시형태에 따른 리튬 이차전지용 음극소재는 Si계 음극 활물질과 그래핀(graphene)으로 이루어진 주성분을 포함하고, 상기 Si계 음극 활물질의 평균입경(Sd)은 30㎚ ~ 1.0㎛이며, 상기 그래핀의 장축 길이(GdL)는 상기 Si계 음극 활물질의 평균입경(Sd)의 30배 이상인 것을 특징으로 한다.The negative electrode material for a lithium secondary battery according to an embodiment of the present invention includes a main component consisting of a Si-based negative active material and graphene, and the average particle diameter (S d ) of the Si-based negative active material is 30 nm to 1.0 μm. , the long axis length (G dL ) of the graphene is 30 times or more of the average particle diameter (S d ) of the Si-based negative active material.

상기 그래핀의 장축 길이(GdL)는 5.0㎛ ~ 40㎛인 것이 바람직하다.The long axis length (G dL ) of the graphene is preferably 5.0 μm to 40 μm.

상기 Si계 음극 활물질과 그래핀(graphene)의 중량비는 4 : 6인 것이 바람직하다.The weight ratio of the Si-based negative active material to graphene is preferably 4:6.

상기 주성분에 PAA, PVA, LiPAA, SBR, CMC, PEDOT:PSS 및 SDBS 중 적어도 1종 이상의 바인더가 더 혼합되는 것을 특징으로 한다.At least one binder of PAA, PVA, LiPAA, SBR, CMC, PEDOT:PSS and SDBS is further mixed with the main component.

상기 음극소재는 주성분: 80 ~ 99.5wt%와 바인더: 0.5 ~ 20wt%로 이루어지는 것이 바람직하다.The negative electrode material is preferably composed of a main component: 80 to 99.5 wt% and a binder: 0.5 to 20 wt%.

상기 주성분에 그래핀나노리본(GNR)이 더 혼합되는 것을 특징으로 한다.It is characterized in that the graphene nano-ribbon (GNR) is further mixed with the main component.

상기 음극소재는 주성분: 98 ~ 99.5wt%와 그래핀나노리본(GNR): 0.5 ~ 2wt%로 이루어지는 것이 바람직하다.The anode material is preferably composed of a main component: 98 to 99.5 wt% and graphene nanoribbon (GNR): 0.5 to 2 wt%.

상기 음극소재는 상기 Si계 음극 활물질의 중량과 상기 그래핀(graphene) 및 그래핀나노리본(GNR)의 중량합의 비율이 4 : 6인 것이 바람직하다.The negative electrode material preferably has a ratio of the weight of the Si-based negative active material to the sum of the weights of graphene and graphene nanoribbon (GNR) of 4:6.

상기 그래핀나노리본(GNR)의 지름은 100 ~ 250㎚인 것이 바람직하다.The diameter of the graphene nanoribbon (GNR) is preferably 100 ~ 250nm.

상기 그래핀의 구형도(sphericity)는 0.7 이상인 것이 바람직하다.Preferably, the graphene has a sphericity of 0.7 or more.

상기 그래핀은 Raman Spectra 측정치 피크의 ID/IG 값이 0.6 ~ 0.7이고, XRD 패턴에서 2θ = 26° 및 2θ = 43 ~ 44°에 피크가 동시에 존재하며, 전기저항 값이 1.0 X 10-3 ~ 9.9 X 10-3 Ωm인 것이 바람직하다.The graphene has an I D /I G value of 0.6 to 0.7 of the Raman Spectra measurement peak, and peaks at 2θ = 26° and 2θ = 43 to 44° in the XRD pattern at the same time, and an electrical resistance value of 1.0 X 10 - It is preferable that it is 3 ~ 9.9 X 10 -3 Ωm.

상기 Si계 음극 활물질은 Si, SiO 및 Si 합금 중 어느 하나 또는 그 이상인 것이 바람직하다.The Si-based negative active material is preferably any one or more of Si, SiO, and a Si alloy.

한편, 본 발명의 일 실시형태에 따른 리튬 이차전지용 음극소재의 제조방법은 순수(H2O)에 Si계 음극 활물질과 그래핀을 혼합하여 전극용액을 준비하는 단계와; 준비된 전극용액을 공기 제어식 전자분무법(Air-controlled electrospray)을 이용하여 전극 성형물을 준비하는 단계와; 준비된 전극 성형물을 열처리하는 단계를 포함한다.On the other hand, the method of manufacturing a negative electrode material for a lithium secondary battery according to an embodiment of the present invention comprises the steps of preparing an electrode solution by mixing a Si-based negative active material and graphene in pure water (H 2 O); preparing an electrode molding using the prepared electrode solution using an air-controlled electrospray; and heat-treating the prepared electrode molding.

상기 전극용액을 준비하는 단계는, 순수(H2O)에 Si계 음극 활물질을 혼합하여 예비 전극용액을 준비하는 과정과; 예비 전극용액에 산화 그래핀을 추가로 혼합하여 전극용액을 준비하는 과정을 포함한다.The preparing of the electrode solution includes: preparing a preliminary electrode solution by mixing a Si-based negative active material with pure water (H 2 O); It includes the process of preparing an electrode solution by further mixing graphene oxide with the preliminary electrode solution.

상기 열처리하는 단계는 상기 전극용액에 혼합된 산화 그래핀을 환원시키는 단계인 것을 특징으로 한다.The heat treatment is characterized in that the reduction of the graphene oxide mixed in the electrode solution.

본 발명의 실시예에 따르면, 음극 전극 내 Si계 음극 활물질과 전기 전도기능을 부여하는 도전재의 최적 조합을 도출하여 배터리셀의 초기효율을 우수하게 유지하면서도 내구열화 특성을 개선할 수 있다.According to an embodiment of the present invention, it is possible to improve the durability deterioration characteristics while maintaining excellent initial efficiency of the battery cell by deriving an optimal combination of the Si-based negative active material in the negative electrode and the conductive material imparting an electric conduction function.

또한, 음극 활물질로 저가의 Si계 물질을 사용하여 음극소재의 제조 비용을 절감할 수 있는 효과를 기대할 수 있다.In addition, an effect of reducing the manufacturing cost of the negative electrode material can be expected by using an inexpensive Si-based material as the negative electrode active material.

도 1a 및 도 1b는 본 발명의 실시예에 따른 리튬 이차전지용 음극소재를 보여주는 도면이고,
도 2는 본 발명의 실시예에 따른 리튬 이차전지용 음극소재를 설명하기 위한 도면이며,
도 3은 본 발명의 실시예에 따른 리튬 이차전지용 음극소재를 보여주는 사진이고,
도 4a 내지 도 6b는 실험 1 내지 3의 각 샘플에 대한 사이클당 전극의 용량(Specific Capacity) 그래프이며,
도 7 내지 도 11은 서로 다른 종류의 그래핀 샘플에 대한 정보를 보여주는 도면이다.1A and 1B are views showing a negative electrode material for a lithium secondary battery according to an embodiment of the present invention;
2 is a view for explaining a negative electrode material for a lithium secondary battery according to an embodiment of the present invention,
3 is a photograph showing a negative electrode material for a lithium secondary battery according to an embodiment of the present invention;
4A to 6B are graphs of the capacity (Specific Capacity) of the electrode per cycle for each sample of Experiments 1 to 3,
7 to 11 are views showing information on different types of graphene samples.

이하, 첨부된 도면을 참조하여 본 발명의 실시예를 더욱 상세히 설명하기로 한다. 그러나 본 발명은 이하에서 개시되는 실시예에 한정되는 것이 아니라 서로 다른 다양한 형태로 구현될 것이며, 단지 본 실시예들은 본 발명의 개시가 완전하도록 하며, 통상의 지식을 가진 자에게 발명의 범주를 완전하게 알려주기 위해 제공되는 것이다.Hereinafter, embodiments of the present invention will be described in more detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in a variety of different forms, only these embodiments allow the disclosure of the present invention to be complete, and the scope of the invention to those of ordinary skill in the art completely It is provided to inform you.

도 1a 및 도 1b는 본 발명의 실시예에 따른 리튬 이차전지용 음극소재를 보여주는 도면이고, 도 2는 본 발명의 실시예에 따른 리튬 이차전지용 음극소재를 설명하기 위한 도면이며, 도 3은 본 발명의 실시예에 따른 리튬 이차전지용 음극소재를 보여주는 사진이다.1A and 1B are views showing a negative electrode material for a lithium secondary battery according to an embodiment of the present invention, FIG. 2 is a view for explaining a negative electrode material for a lithium secondary battery according to an embodiment of the present invention, and FIG. 3 is the present invention It is a photograph showing an anode material for a lithium secondary battery according to an embodiment.

도면에 도시된 바와 같이 본 발명의 실시예에 따른 리튬 이차전지용 음극소재는 일반적인 음극소재와 마찬가지로 음극 활물질과 전기 전도기능을 부여하는 도전재 성분이 혼합되어 이루어진다.As shown in the drawings, the negative electrode material for a lithium secondary battery according to an embodiment of the present invention is made by mixing a negative electrode active material and a conductive material component that imparts an electrical conductivity function, like a general negative electrode material.

이때 음극 활물질(20, 20a, 20b)은 Si계 음극 활물질이 사용된다. 예를 들어 Si계 음극 활물질(20, 20a, 20b)은 Si, SiO 및 Si 합금 중 어느 하나 또는 그 이상의 조합으로 이루어질 수 있다. 본 실시예에서는 음극 활물질로 Si 입자를 사용하였다.At this time, the negative active material 20, 20a, 20b is a Si-based negative active material is used. For example, the Si-based negative active materials 20 , 20a , and 20b may be formed of any one or a combination of Si, SiO, and a Si alloy. In this embodiment, Si particles were used as the anode active material.

그리고, 도전재로는 탄소 동소체 중 하나인 그래핀(graphene, 30)이 사용된다. 그래서 본 실시예에서는 Si계 음극 활물질(20, 20a, 20b)과 그래핀(30)이 혼합된 주성분을 집전체와 같은 기재(10)의 표면에 도포하여 음극을 형성시킨다.In addition, graphene (30), which is one of the carbon allotropes, is used as the conductive material. Therefore, in this embodiment, the main component in which the Si-based negative active materials 20 , 20a , 20b and graphene 30 are mixed is applied to the surface of the substrate 10 such as a current collector to form a negative electrode.

한편, 본 실시예에서는 음극 활물질로 사용되는 Si계 입자의 평균입경(Sd)이 30㎚ ~ 1.0㎛인 것이 바람직하다.Meanwhile, in this embodiment, it is preferable that the average particle diameter (S d ) of the Si-based particles used as the negative electrode active material is 30 nm to 1.0 μm.

그리고, 도전재로 사용되는 그래핀의 장축 길이(GdL)는 음극 활물질인 Si계 입자 평균입경의 30배 이상인 것을 만족하면서 5.0㎛ ~ 40㎛인 것이 바람직하다.And, it is preferable that the long axis length (G dL ) of graphene used as a conductive material is 5.0 μm to 40 μm while satisfying that it is 30 times or more of the average particle diameter of Si-based particles as a negative electrode active material.

이때 Si계 입자의 평균입경(Sd)과 그래핀의 장축 길이(GdL)는 도 2와 같이 표현될 수 있다.At this time, the average particle diameter (S d ) of the Si-based particles and the long axis length (G dL ) of the graphene may be expressed as shown in FIG. 2 .

한편, 본 실시예에서는 음극 활물질의 크기 및 도전재의 성분, 형상 및 비율 등을 최적화하여 음극 활물질의 혼합비율을 향상시켰으며, 바람직하게는 음극 활물질인 Si 입자와 도전재인 그래핀(graphene)의 중량비를 4 : 6으로 배합하는 것이 바람직하다. Meanwhile, in this embodiment, the mixing ratio of the negative electrode active material was improved by optimizing the size of the negative active material and the components, shape and ratio of the conductive material, and preferably, the weight ratio of Si particles as the negative electrode active material and graphene as the conductive material. It is preferable to mix with 4:6.

이때 그래핀의 구형도(sphericity)는 0.7 이상인 것이 바람직하다.In this case, the graphene preferably has a sphericity of 0.7 or more.

특히, 그래핀은 Raman Spectra 측정치 피크의 ID/IG 값이 0.6 ~ 0.7이고, XRD 패턴에서 2θ = 26° 및 2θ = 43 ~ 44°에 피크가 동시에 존재하며, 전기저항 값이 1.0 X 10-3 ~ 9.9 X 10-3 Ωm인 것을 만족하는 것이 바람직하다.In particular, graphene has an I D /I G value of 0.6 to 0.7 of the Raman Spectra measured peak, and peaks at 2θ = 26° and 2θ = 43 to 44° in the XRD pattern simultaneously, and an electrical resistance value of 1.0 X 10 It is preferable to satisfy -3 to 9.9 X 10 -3 Ωm.

그리고, 본 실시예에서 음극소재는 음극 활물질과 도전재로 이루어진 주성분에 바인더를 더 혼합할 수 있다. 이때 바인더로는 PAA, PVA, LiPAA, SBR, CMC, PEDOT:PSS 및 SDBS 중 적어도 1종 이상의 바인더가 사용될 수 있다.And, in the present embodiment, the negative electrode material may further mix a binder with the main component consisting of the negative electrode active material and the conductive material. In this case, at least one binder of PAA, PVA, LiPAA, SBR, CMC, PEDOT:PSS, and SDBS may be used as the binder.

또한, 주성분: 80 ~ 99.5wt%와 바인더: 0.5 ~ 20wt%를 혼합하여 음극소재를 형성하는 것이 바람직하다.In addition, it is preferable to form the negative electrode material by mixing the main component: 80 to 99.5 wt% and the binder: 0.5 to 20 wt%.

그리고, 본 실시예에서는 주성분에 혼합되는 도전재로 그래핀과 함께 그래핀나노리본(GNR)이 더 혼합될 수 있다.And, in this embodiment, graphene nanoribbon (GNR) may be further mixed with graphene as a conductive material mixed with the main component.

이때 주성분: 98 ~ 99.5wt%와 그래핀나노리본(GNR): 0.5 ~ 2wt%를 혼합하여 음극소재를 형성하는 것이 바람직하다.At this time, it is preferable to form the negative electrode material by mixing the main component: 98 ~ 99.5 wt% and graphene nanoribbon (GNR): 0.5 ~ 2 wt%.

다만, 그래핀나노리본(GNR)의 혼합량 만큼 그래핀의 혼합량을 줄여서 Si 입자의 중량과 그래핀(graphene) 및 그래핀나노리본(GNR)의 중량합의 비율이 4 : 6를 유지하도록 하는 것이 바람직하다.However, it is preferable to reduce the mixing amount of graphene by the amount of graphene nano-ribbons (GNR) so that the ratio of the weight of Si particles to the sum of the weights of graphene and graphene nano-ribbons (GNR) is 4:6. Do.

그리고, 그래핀나노리본(GNR)의 지름은 100 ~ 250㎚인 것이 바람직하다.And, it is preferable that the diameter of the graphene nano-ribbon (GNR) is 100 to 250 nm.

상기와 같이 음극소재를 형성하는 음극 활물질 및 도전재의 종류, 형상, 비율 등을 한정하는 이유에 대해서는 이후에 실험 및 그 결과를 통하여 설명하도록 한다.The reason for limiting the type, shape, ratio, etc. of the negative electrode active material and the conductive material forming the negative electrode material as described above will be described later through experiments and the results.

한편, 상기와 같이 구성되는 리튬 이차전지용 음극소재의 제조방법은 다음과 같다.On the other hand, the manufacturing method of the negative electrode material for a lithium secondary battery configured as described above is as follows.

본 발명의 실시예에 따른 리튬 이차전지용 음극소재를 제조하기 위해서는 먼저 전극용액을 준비한다.In order to prepare a negative electrode material for a lithium secondary battery according to an embodiment of the present invention, an electrode solution is first prepared.

전극용액은 순수(H2O)에 Si계 음극 활물질과 그래핀을 혼합하여 준비한다.The electrode solution is prepared by mixing Si-based negative active material and graphene in pure water (H 2 O).

전극용액을 준비하기 위하여 순수(H2O)에 Si계 음극 활물질을 혼합하여 예비 전극용액을 준비한다. 예비 전극용액에 대하여 초음파 분산을 1시간 실시하여 순수에 Si계 음극 활물질이 고르게 분산되도록 한다.To prepare an electrode solution, a preliminary electrode solution is prepared by mixing a Si-based negative active material with pure water (H 2 O). Ultrasonic dispersion is performed on the preliminary electrode solution for 1 hour so that the Si-based negative active material is evenly dispersed in pure water.

그리고, 준비된 예비 전극용액에 순수(H2O)와 함께 산화 그래핀을 추가로 혼합하여 전극용액을 준비한다. 마찬가지로 전극용액에 대하여 초음파 분산을 1시간 실시하여 순수에 Si계 음극 활물질과 산화 그래핀이 고르게 분산되도록 한다.Then, an electrode solution is prepared by further mixing graphene oxide with pure water (H 2 O) in the prepared preliminary electrode solution. Similarly, ultrasonic dispersion of the electrode solution is performed for 1 hour so that the Si-based negative active material and graphene oxide are evenly dispersed in pure water.

이렇게 전극용액이 준비되면, 준비된 전극용액을 공기 제어식 전자분무법(Air-controlled electrospray)을 이용하여 전극 성형물을 준비한다.When the electrode solution is prepared in this way, an electrode molding is prepared using the prepared electrode solution using an air-controlled electrospray method.

부연하자면, 전압을 부여할 수 있는 전자분무 노즐을 통하여 전극용액을 분무하면서 전자분무 노즐에 약 25KV의 전압을 인가한다. 그러면 전극용액이 에어로졸 또는 플럼(piume)과 같은 형태로 분사되면서 전자분무 노즐의 전방에 배치된 집전체와 같은 기재의 표면에 전극용액이 도포된다.In other words, a voltage of about 25KV is applied to the electrospray nozzle while spraying the electrode solution through the electrospray nozzle capable of applying a voltage. Then, while the electrode solution is sprayed in the form of an aerosol or a plume, the electrode solution is applied to the surface of a substrate such as a current collector disposed in front of the electrospray nozzle.

이때 전자분무 노즐로 공급되는 전극용액의 공급속도는 0.04㎖/min을 유지하고, 전자분무 노즐과 기재 사이의 거리는 20㎜를 유지하는 것이 바람직하다.At this time, it is preferable to maintain the supply rate of the electrode solution supplied to the electrospray nozzle at 0.04ml/min, and maintain the distance between the electrospray nozzle and the substrate at 20mm.

이렇게 전극용액을 기재의 표면에 도포하여 전극 성형물이 준비되면, 이를 열처리한다.When the electrode solution is applied to the surface of the substrate in this way to prepare an electrode molded product, it is heat-treated.

이때 열처리는 환원분위기에서 실시하여 전극용액에 혼합된 산화 그래핀을 환원시킨다. 이를 위하여 전극 성형물을 질소 분위기의 환원로에 투입하고 400℃의 온도에서 2시간 동안 열처리하여 전극 성형물을 형성하고 있는 산화 그래핀을 환원시킨다.At this time, the heat treatment is performed in a reducing atmosphere to reduce the graphene oxide mixed in the electrode solution. To this end, the electrode molding is put into a reduction furnace in a nitrogen atmosphere and heat-treated at a temperature of 400° C. for 2 hours to reduce graphene oxide forming the electrode molding.

다음으로, 비교예 및 실시예를 통하여 본 발명을 설명한다.Next, the present invention will be described through comparative examples and examples.

먼저, 비교예 및 실시예에 따른 음극재 샘플을 마련하기 위하여 전술된 음극소재의 제조방법에 따라 음극을 제조한다. 이때 음극 활물질로는 Si 입자를 사용하였다.First, in order to prepare negative electrode material samples according to Comparative Examples and Examples, a negative electrode is prepared according to the above-described method for preparing negative electrode material. In this case, Si particles were used as the negative active material.

한편, 실험 1은 Si 입자의 크기를 30 ~ 50㎚(Dmax = 50㎚, Dmin = 30㎚, D50 = 40㎚)로 하면서, 그래핀의 장축 길이(GdL)를 각각 5㎛, 10㎛ 및 40㎛로 변경하여 혼합하였다.On the other hand, in Experiment 1, while the size of the Si particles was 30 to 50 nm (Dmax = 50 nm, Dmin = 30 nm, D50 = 40 nm), the major axis length (G dL ) of graphene was 5 μm, 10 μm, and Changed to 40㎛ and mixed.

이렇게 마련된 각 음극재 샘플(도 1a)에 대하여 1st cycle 용량(mAh/g)과 1st cycle 효율(%)을 측정하였고, 그 결과를 하기의 표 1에 나타내었다.1st cycle capacity (mAh/g) and 1st cycle efficiency (%) were measured for each negative electrode material sample prepared in this way (FIG. 1a), and the results are shown in Table 1 below.

그리고, 실험 2는 Si 입자의 크기를 60 ~ 900㎚(Dmax = 900㎚, Dmin = 60㎚, D50 = 300㎚)로 하면서, 그래핀의 장축 길이(GdL)를 각각 5㎛, 10㎛ 및 40㎛로 변경하여 혼합하였다.And, in Experiment 2, while the size of the Si particles is 60 ~ 900 nm (Dmax = 900 nm, Dmin = 60 nm, D50 = 300 nm), the major axis length (G dL ) of graphene is 5 μm, 10 μm, and Changed to 40㎛ and mixed.

이렇게 마련된 각 음극재 샘플(도 1b)에 대하여 1st cycle 용량(mAh/g)과 1st cycle 효율(%)을 측정하였고, 그 결과를 하기의 표 1에 나타내었다.1st cycle capacity (mAh/g) and 1st cycle efficiency (%) were measured for each negative electrode material sample prepared in this way (FIG. 1b), and the results are shown in Table 1 below.

그리고, 실험 3은 Si 입자의 크기를 60 ~ 900㎚(Dmax = 900㎚, Dmin = 60㎚, D50 = 300㎚)로 하고, 그래핀의 장축 길이(GdL)를 40㎛로 하면서, 그래핀나노리본(GNR)의 혼합량을 0wt%, 1wt%, 2wt% 및 5wt%로 변경하면서 혼합하였다. 이때 그래핀나노리본(GNR)의 혼합량만큼 그래핀의 혼합량을 감량하였다.And, in Experiment 3, the size of the Si particles was 60 ~ 900 nm (Dmax = 900 nm, Dmin = 60 nm, D50 = 300 nm), and the long axis length (G dL ) of graphene was 40 μm, graphene Nanoribbon (GNR) was mixed while changing the mixing amount to 0wt%, 1wt%, 2wt% and 5wt%. At this time, the amount of graphene mixing was reduced by the amount of graphene nanoribbon (GNR).

이렇게 마련된 각 음극재 샘플에 대하여 1st cycle 용량(mAh/g)과 1st cycle 효율(%)을 측정하였고, 그 결과를 하기의 표 1에 나타내었다.1st cycle capacity (mAh/g) and 1st cycle efficiency (%) were measured for each negative electrode material sample thus prepared, and the results are shown in Table 1 below.

구 분division GdL/SdGdL/Sd 1st cycle 용량
(mAh/g) 1 st cycle capacity
(mAh/g) 1st cycle 효율
(%)1 st cycle efficiency
(%) 비고note 실험1Experiment 1 GdL: 5㎛GdL: 5 μm 125125 21002100 7676 실시예Example GdL: 10㎛GdL: 10 μm 250250 24002400 7777 실시예Example GdL: 40㎛GdL: 40 μm 10001000 27002700 7676 실시예Example 실험2Experiment 2 GdL: 5㎛GdL: 5 μm 16.716.7 500500 5757 비교예comparative example GdL: 10㎛GdL: 10 μm 33.333.3 11001100 7171 실시예Example GdL: 40㎛GdL: 40 μm 133.3133.3 16001600 7474 실시예Example 실험3Experiment 3 GNR: 0wt%GNR: 0wt% 133.3133.3 17001700 8585 비교예comparative example GNR: 1wt%GNR: 1wt% 133.3133.3 22002200 8585 비교예comparative example GNR: 2wt%GNR: 2wt% 133.3133.3 21002100 8484 실시예Example GNR: 5wt%GNR: 5wt% 133.3133.3 21002100 8484 실시예Example

표 1에서 확인할 수 있듯이, 실험 1의 경우 모든 음극재 샘플이 GdL/Sd의 값이 30을 초과함에 따라 그래핀의 장축 길이(GdL)에 상관없이 1st cycle 용량(mAh/g)과 1st cycle 효율(%)이 양호한 것을 확인할 수 있었다.As can be seen in Table 1, in the case of Experiment 1, as the GdL/Sd value of all anode material samples exceeded 30, the 1st cycle capacity (mAh/g) and 1st cycle regardless of the long axis length (G dL ) of graphene It was confirmed that the efficiency (%) was good.

반면에, 실험 2의 경우 그래핀의 장축 길이(GdL)가 증가함에 따라 1st cycle 용량(mAh/g)과 1st cycle 효율(%)이 증가하였지만, Si 입자의 크기가 커짐에 따라 GdL/Sd의 값이 16.7인 비교예는 1st cycle 용량(mAh/g)과 1st cycle 효율(%)이 상당히 낮은 것을 확인할 수 있었다.On the other hand, in the case of Experiment 2, the 1st cycle capacity (mAh/g) and 1st cycle efficiency (%) increased as the long axis length (G dL ) of graphene increased, but as the size of the Si particles increased, GdL/Sd In the comparative example in which the value of is 16.7, it was confirmed that the 1st cycle capacity (mAh/g) and the 1st cycle efficiency (%) were significantly low.

따라서, Si 입자의 크기에 증가에 따라 그래핀 장축 길이(GdL)의 조정이 필요하였고, 실험 결과와 같이 GdL/Sd의 값을 30 이상으로 유지하는 것이 바람직하다는 것을 확인할 수 있었다.Therefore, as the size of the Si particles increased, it was necessary to adjust the graphene major axis length (G dL ), and it was confirmed that it is preferable to maintain the value of GdL/Sd at 30 or more, as shown in the experimental results.

또한, 실험 3의 경우 그래핀나노리본(GNR)의 첨가에 따라 1st cycle 용량(mAh/g)과 1st cycle 효율(%)이 증가하였지만, 그래핀나노리본(GNR)의 혼합량이 2wt%와 5wt%에서는 오히려 1wt%를 첨가하였을 때보다 1st cycle 용량(mAh/g)과 1st cycle 효율(%)이 다소 저하된 것을 확인할 수 있었다.In addition, in the case of Experiment 3, 1st cycle capacity (mAh/g) and 1st cycle efficiency (%) were increased according to the addition of graphene nanoribbon (GNR), but the mixing amount of graphene nanoribbon (GNR) was 2wt% and 5wt %, it was confirmed that the 1st cycle capacity (mAh/g) and 1st cycle efficiency (%) were slightly lower than when 1wt% was added.

따라서, 그래핀나노리본(GNR)의 첨가량은 0.5 ~ 2wt%로 한정하는 것이 바람직하다는 것을 확인할 수 있었다.Therefore, it was confirmed that it is preferable to limit the amount of graphene nanoribbon (GNR) to 0.5 to 2 wt%.

다음으로, 실험 1 내지 실험 3에서 마련된 각 음극재 샘플의 사이클당 전극의 용량(Specific Capacity)을 측정하였고, 그 결과를 도 4a 내지 도 6b에 나타내었다.Next, the capacity (specific capacity) of the electrode per cycle of each negative electrode material sample prepared in Experiments 1 to 3 was measured, and the results are shown in FIGS. 4A to 6B .

도 4a는 실험 1의 각 음극재 샘플에 대한 사이클당 전극의 용량(Specific Capacity) 그래프이고, 도 4b는 실험 2의 각 음극재 샘플에 대한 사이클당 전극의 용량(Specific Capacity) 그래프이며, 도 5는 실험 1 및 실험 2의 각 음극재 샘플에 대한 사이클당 전극의 용량(Specific Capacity) 그래프이고, 도 6a 및 도 6b는 실험 3의 각 음극재 샘플에 대한 사이클당 전극의 용량(Specific Capacity) 그래프이다.Figure 4a is a graph of the capacity (Specific Capacity) of the electrode per cycle for each negative material sample of Experiment 1, Figure 4b is a graph of the capacity (Specific Capacity) of the electrode per cycle for each negative material sample of Experiment 2, Figure 5 is a graph of the capacity (Specific Capacity) of the electrode per cycle for each negative material sample of Experiment 1 and Experiment 2, and FIGS. 6A and 6B are graphs of the capacity (Specific Capacity) of the electrode per cycle for each negative material sample of Experiment 3 am.

도 4a 및 도 4b에서 확인할 수 있듯이, 실험 1 및 실험 2의 경우 모두 0.1C ~ 0.5C 구간의 특성을 보면 그래핀의 장축 길이(GdL)에 상관없이 용량값이 양호한 것을 확인할 수 있었다. 하지만, 1.0C ~ 2C 구간의 특성을 보면 그래핀의 장축 길이(GdL)가 5㎛인 전극재 샘플의 경우 용량값이 다소 열세인 것을 확인할 수 있었다.As can be seen in FIGS. 4A and 4B , in the case of Experiment 1 and Experiment 2, it was confirmed that the capacitance value was good regardless of the major axis length (G dL ) of graphene when looking at the characteristics of the 0.1C ~ 0.5C section. However, looking at the characteristics of the 1.0C ~ 2C section, it was confirmed that the capacitance value was somewhat inferior in the case of the electrode material sample having the major axis length (G dL ) of the graphene 5㎛.

따라서, Si 입자의 크기에 증가에 따라 그래핀 장축 길이(GdL)의 조정이 필요하다는 것을 다시 한번 확인하였고, 실험 결과와 같이 GdL/Sd의 값을 30 이상으로 유지하는 것이 바람직하다는 것을 확인할 수 있었다.Therefore, it was confirmed once again that the graphene major axis length (G dL ) needs to be adjusted according to the increase in the size of the Si particles, and it can be confirmed that it is desirable to maintain the value of GdL/Sd above 30 as shown in the experimental results. there was.

한편, 도 5에서 확인할 수 있듯이, 실험 1의 경우 그래핀의 장축 길이(GdL)에 상관없이 사이클이 늘어나더라도 용량값이 저하되는 기울기가 양호한 것을 확인할 수 있었다.On the other hand, as can be seen in FIG. 5 , in the case of Experiment 1, it was confirmed that the slope at which the capacity value decreased even if the cycle was increased irrespective of the long axis length (G dL ) of the graphene was confirmed to be good.

하지만, 실험 2의 경우 그래핀의 장축 길이(GdL)에 상관없이 사이클이 늘어나더라도 용량값이 저하되는 기울기가 양호하였지만, 용량 산포가 큰 것을 확인할 수 있었다. 특히 그래핀 장축 길이(GdL)의 감소시 용량이 감소한 것을 확인할 수 있었다.However, in the case of Experiment 2, regardless of the major axis length (G dL ) of graphene, the slope at which the capacity value decreased even if the cycle was increased was favorable, but it was confirmed that the capacity dispersion was large. In particular, it was confirmed that the capacity decreased when the graphene major axis length (G dL ) was decreased.

그리고, 도 6a 및 도 6b에서 확인할 수 있듯이, 그래핀나노리본(GNR)의 첨가시 전체 용량 및 효율이 증가하는 것을 확인할 수 있었다.And, as can be seen in FIGS. 6A and 6B , it was confirmed that the total capacity and efficiency were increased when graphene nanoribbons (GNR) were added.

특히, 저율수명(~0.3C) 구간에서는 그래핀나노리본(GNR)를 5wt% 첨가한 음극재 샘플을 제외하고 나머지 음극재 샘플에서는 용량이 양호한 것을 확인할 수 있었다.In particular, in the low-rate life (~0.3C) section, it was confirmed that the capacity was good in the remaining anode material samples except for the anode material sample to which 5 wt% of graphene nanoribbon (GNR) was added.

그리고, 1.0C 구간에서는 그래핀나노리본(GNR)를 1wt% 및 2wt% 첨가한 음극재 샘플이 상대적으로 용량이 우수한 것을 확인할 수 있었다.In addition, in the 1.0C section, it was confirmed that the negative electrode material samples in which 1wt% and 2wt% of graphene nanoribbon (GNR) were added had relatively excellent capacity.

따라서, 그래핀나노리본(GNR)의 첨가량은 0.5 ~ 2wt%로 한정하는 것이 바람직하다는 것을 다시한번 확인할 수 있었다.Therefore, it was confirmed once again that it is preferable to limit the amount of graphene nanoribbon (GNR) to 0.5 to 2 wt%.

다음으로, 그래핀의 종류 및 특성에 대한 최적의 조건에 대하여 설명한다.Next, optimal conditions for types and properties of graphene will be described.

여러 형태의 그래핀 샘플을 사용하여 전술된 음극소재의 제조방법에 따라 음극을 제조하였다.Using various types of graphene samples, a negative electrode was prepared according to the method for preparing the negative electrode material described above.

이때 각 그래핀의 샘플 외관 사진을 도 7에 나타내었다.At this time, a photograph of the sample appearance of each graphene is shown in FIG. 7 .

그리고, 각 샘플에 대한 Raman Spectra 측정치 피크의 ID/IG 값을 도 8에 나타내었고, 각 샘플에 대한 XRD 패턴을 도 9에 나타내었으며, 각 샘플에 대한 FT-IR 적외선 분광법을 실시하여 그 결과를 도 10에 나타내었다.And, the ID / IG value of the Raman Spectra measurement peak for each sample is shown in FIG. 8, the XRD pattern for each sample is shown in FIG. 9, FT-IR infrared spectroscopy for each sample was performed, and the result It is shown in Figure 10.

또한, 각 샘플의 전기저항 값 및 구형도를 측정하여 하기의 표 2에 나타내었다. 이때 샘플 D3는 흑연으로서 평가에서 제외하였다.In addition, the electrical resistance value and sphericity of each sample were measured and shown in Table 2 below. At this time, sample D3 was excluded from evaluation as graphite.

구분division Resistivity*10-3 (Ωm)Resistivity*10-3 (Ωm) SphericitySphericity D1D1 12.312.3 0.720.72 A1A1 27.427.4 0.5260.526 D2D2 3838 0.9510.951 K1K1 12.612.6 0.5450.545 K2K2 1.671.67 0.730.73 D3D3 1.471.47 --

상기와 같은 특성을 갖는 각 그래핀의 샘플을 이용하여 전술된 음극소재의 제조방법에 따라 음극 샘플을 제작한 다음 셀 용량 및 효율을 측정하였고, 그 결과를 도 11 및 표 3에 나타내었다.Using each graphene sample having the above characteristics, a negative electrode sample was prepared according to the above-described method for preparing a negative electrode material, and then cell capacity and efficiency were measured, and the results are shown in FIG. 11 and Table 3.

구분division D1D1 A1A1 K2K2 D2D2 K1K1 Charge
(mAh/g) Charge
(mAh/g) 1725.61725.6 2115.92115.9 1753.31753.3 2023.92023.9 2066.72066.7 Discharge (mAh/g)Discharge (mAh/g) 1483.11483.1 1574.31574.3 1537.71537.7 1599.51599.5 1581.81581.8 Eff. (%)Eff. (%) 77.777.7 74.474.4 83.783.7 78.678.6 76.676.6

도 11 및 표 3에서 확인할 수 있듯이, 전기 저항이 낮고, 관능기(C-O-C, C=O) 가 거의 없는 샘플 K2가 높은 효율을 보이는 것을 확인할 수 있었다.11 and Table 3, it was confirmed that sample K2 having low electrical resistance and almost no functional groups (C-O-C, C=O) exhibited high efficiency.

본 발명을 첨부 도면과 전술된 바람직한 실시예를 참조하여 설명하였으나, 본 발명은 그에 한정되지 않으며, 후술되는 특허청구범위에 의해 한정된다. 따라서, 본 기술분야의 통상의 지식을 가진 자라면 후술되는 특허청구범위의 기술적 사상에서 벗어나지 않는 범위 내에서 본 발명을 다양하게 변형 및 수정할 수 있다.Although the present invention has been described with reference to the accompanying drawings and the above-described preferred embodiments, the present invention is not limited thereto, and is defined by the claims described below. Accordingly, those of ordinary skill in the art can variously change and modify the present invention within the scope without departing from the spirit of the claims to be described later.

10: 기재
20, 20a, 20b: 음극 활물질
30: 그래핀10: description
20, 20a, 20b: negative active material
30: graphene

Claims (15)

Si계 음극 활물질과 그래핀(graphene)으로 이루어진 주성분을 포함하고,
상기 Si계 음극 활물질의 평균입경(Sd)은 30㎚ ~ 1.0㎛이며,
상기 그래핀의 장축 길이(GdL)는 상기 Si계 음극 활물질의 평균입경(Sd)의 30배 이상인 것을 특징으로 하는 리튬 이차전지용 음극소재.
It contains a main component consisting of a Si-based negative active material and graphene,
The Si-based negative active material has an average particle diameter (S d ) of 30 nm to 1.0 μm,
The long axis length (G dL ) of the graphene is an anode material for a lithium secondary battery, characterized in that 30 times or more of the average particle diameter (S d ) of the Si-based anode active material.
 청구항 1에 있어서,
상기 그래핀의 장축 길이(GdL)는 5.0㎛ ~ 40㎛인 것을 특징으로 하는 리튬 이차전지용 음극소재.
The method according to claim 1,
The long-axis length (G dL ) of the graphene is a negative electrode material for a lithium secondary battery, characterized in that 5.0㎛ ~ 40㎛.
 청구항 1에 있어서,
상기 Si계 음극 활물질과 그래핀(graphene)의 중량비는 4 : 6인 것을 특징으로 하는 리튬 이차전지용 음극소재.
The method according to claim 1,
A negative electrode material for a lithium secondary battery, characterized in that the weight ratio of the Si-based negative active material and graphene is 4:6.
 청구항 1에 있어서,
상기 주성분에 PAA, PVA, LiPAA, SBR, CMC, PEDOT:PSS 및 SDBS 중 적어도 1종 이상의 바인더가 더 혼합되는 것을 특징으로 하는 리튬 이차전지용 음극소재.
The method according to claim 1,
At least one binder of PAA, PVA, LiPAA, SBR, CMC, PEDOT:PSS and SDBS is further mixed with the main component.
 청구항 4에 있어서,
상기 음극소재는 주성분: 80 ~ 99.5wt%와 바인더: 0.5 ~ 20wt%로 이루어지는 것을 특징으로 하는 리튬 이차전지용 음극소재.
5. The method according to claim 4,
The negative electrode material is a negative electrode material for a lithium secondary battery, characterized in that consisting of a main component: 80 ~ 99.5 wt% and a binder: 0.5 ~ 20 wt%.
 청구항 1에 있어서,
상기 주성분에 그래핀나노리본(GNR)이 더 혼합되는 것을 특징으로 하는 리튬 이차전지용 음극소재.
The method according to claim 1,
A negative electrode material for a lithium secondary battery, characterized in that graphene nanoribbon (GNR) is further mixed with the main component.
 청구항 6에 있어서,
상기 음극소재는 주성분: 98 ~ 99.5wt%와 그래핀나노리본(GNR): 0.5 ~ 2wt%로 이루어지는 것을 특징으로 하는 리튬 이차전지용 음극소재.
7. The method of claim 6,
The anode material is a negative electrode material for a lithium secondary battery, characterized in that the main component: 98 ~ 99.5wt% and graphene nanoribbon (GNR): 0.5 ~ 2wt%.
 청구항 7에 있어서,
상기 음극소재는 상기 Si계 음극 활물질의 중량과 상기 그래핀(graphene) 및 그래핀나노리본(GNR)의 중량합의 비율이 4 : 6인 것을 특징으로 하는 리튬 이차전지용 음극소재.
8. The method of claim 7,
The negative electrode material is a negative electrode material for a lithium secondary battery, characterized in that the ratio of the weight of the Si-based negative active material to the sum of the weight of graphene and graphene nanoribbon (GNR) is 4:6.
 청구항 6에 있어서,
상기 그래핀나노리본(GNR)의 지름은 100 ~ 250㎚인 것을 특징으로 하는 리튬 이차전지용 음극소재.
7. The method of claim 6,
The anode material for a lithium secondary battery, characterized in that the graphene nanoribbon (GNR) has a diameter of 100 to 250 nm.
 청구항 1에 있어서,
상기 그래핀의 구형도(sphericity)는 0.7 이상인 것을 특징으로 하는 리튬 이차전지용 음극소재.
The method according to claim 1,
The negative electrode material for a lithium secondary battery, characterized in that the sphericity (sphericity) of the graphene is 0.7 or more.
 청구항 1에 있어서,
상기 그래핀은 Raman Spectra 측정치 피크의 ID/IG 값이 0.6 ~ 0.7이고, XRD 패턴에서 2θ = 26° 및 2θ = 43 ~ 44°에 피크가 동시에 존재하며, 전기저항 값이 1.0 X 10-3 ~ 9.9 X 10-3 Ωm인 것을 특징으로 하는 리튬 이차전지용 음극소재.
The method according to claim 1,
The graphene has an I D /I G value of 0.6 to 0.7 of the Raman Spectra measurement peak, and peaks at 2θ = 26° and 2θ = 43 to 44° in the XRD pattern at the same time, and an electrical resistance value of 1.0 X 10 - Anode material for lithium secondary batteries, characterized in that 3 ~ 9.9 X 10 -3 Ωm.
 청구항 1에 있어서,
상기 Si계 음극 활물질은 Si, SiO 및 Si 합금 중 어느 하나 또는 그 이상인 것을 특징으로 하는 리튬 이차전지용 음극소재.
The method according to claim 1,
The Si-based negative active material is a negative electrode material for a lithium secondary battery, characterized in that any one or more of Si, SiO and Si alloy.
 순수(H2O)에 Si계 음극 활물질과 그래핀을 혼합하여 전극용액을 준비하는 단계와;
준비된 전극용액을 공기 제어식 전자분무법(Air-controlled electrospray)을 이용하여 전극 성형물을 준비하는 단계와;
준비된 전극 성형물을 열처리하는 단계를 포함하는 리튬 이차전지용 음극소재의 제조방법.
preparing an electrode solution by mixing Si-based negative active material and graphene in pure water (H 2 O);
preparing an electrode molding using the prepared electrode solution using an air-controlled electrospray;
A method of manufacturing a negative electrode material for a lithium secondary battery comprising the step of heat-treating the prepared electrode molding.
 청구항 13에 있어서,
상기 전극용액을 준비하는 단계는,
순수(H2O)에 Si계 음극 활물질을 혼합하여 예비 전극용액을 준비하는 과정과;
예비 전극용액에 산화 그래핀을 추가로 혼합하여 전극용액을 준비하는 과정을 포함하는 리튬 이차전지용 음극소재의 제조방법.
14. The method of claim 13,
The step of preparing the electrode solution,
A process of preparing a preliminary electrode solution by mixing a Si-based negative active material with pure water (H 2 O);
A method of manufacturing a negative electrode material for a lithium secondary battery, comprising the step of preparing an electrode solution by additionally mixing graphene oxide with a preliminary electrode solution.
 청구항 14에 있어서,
상기 열처리하는 단계는 상기 전극용액에 혼합된 산화 그래핀을 환원시키는 단계인 것을 특징으로 하는 리튬 이차전지용 음극소재의 제조방법.
15. The method of claim 14,
The heat treatment step is a method of manufacturing a negative electrode material for a lithium secondary battery, characterized in that the step of reducing the graphene oxide mixed in the electrode solution.
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