KR20070059569A - Anode active material for lithium secondary battery having coating layer of carbon and non-carbon material and preparation thereof - Google Patents

Anode active material for lithium secondary battery having coating layer of carbon and non-carbon material and preparation thereof Download PDF

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KR20070059569A
KR20070059569A KR1020050118560A KR20050118560A KR20070059569A KR 20070059569 A KR20070059569 A KR 20070059569A KR 1020050118560 A KR1020050118560 A KR 1020050118560A KR 20050118560 A KR20050118560 A KR 20050118560A KR 20070059569 A KR20070059569 A KR 20070059569A
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carbon
lithium secondary
active material
graphite powder
secondary battery
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이상은
최임구
박철완
이형동
최현기
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주식회사 소디프신소재
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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
    • H01M4/362—Composites
    • H01M4/366—Composites as layered products
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B25/00—Phosphorus; Compounds thereof
    • C01B25/08—Other phosphides
    • C01B25/082—Other phosphides of boron, aluminium, gallium or indium
    • C01B25/085—Other phosphides of boron, aluminium, gallium or indium of aluminium
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B32/00—Carbon; Compounds thereof
    • C01B32/05—Preparation or purification of carbon not covered by groups C01B32/15, C01B32/20, C01B32/25, C01B32/30
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B32/00—Carbon; Compounds thereof
    • C01B32/20—Graphite
    • C01B32/21—After-treatment
    • 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
    • H01M4/58—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
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/80—Particles consisting of a mixture of two or more inorganic phases
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/40—Electric properties
    • 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

A negative electrode active material for a lithium secondary battery is provided to improve the capacity and lifespan of a battery by suppressing separation of active material components from an electrode plate when a lithium battery is charged and discharged. The negative electrode active material for a lithium secondary battery is prepared by the steps of: (1) dissolving a carbon material in an organic solvent to obtain a sol solution; (2) adding a non-carbon component-containing material on the periodic table, which is solid at ambient temperature, to the sol solution, followed by thereto adding an alkaline material and stirring the admixture to obtain a gel solution; (3) adding graphite powder to the gel solution and stirring the admixture to form a carbon material/non-carbon material composite gel coating layer on the surface of the graphite powder; and (4) drying and firing the coated graphite powder.

Description

탄소-비탄소 성분 구조의 피복층을 갖는 리튬 이차전지용 음극 활물질 및 이의 제조방법 {ANODE ACTIVE MATERIAL FOR LITHIUM SECONDARY BATTERY HAVING COATING LAYER OF CARBON AND NON-CARBON MATERIAL AND PREPARATION THEREOF} Anode active material for a lithium secondary battery having a coating layer of carbon-non-carbon component structure and a method of manufacturing the same

도 1은 본 발명에 따라 흑연에 탄소재-비탄소재로 된 복합체 층이 피복된 구조를 나타낸 모식도이고, 1 is a schematic diagram showing a structure in which a composite layer of carbon material-non-carbon material is coated on graphite according to the present invention,

도 2는 본 발명의 탄소재-비탄소재 복합체-피복된 흑연의 EDAX (energy dispersive X-ray analysis) 분석도이며;2 is an energy dispersive X-ray analysis (EDAX) analysis of the carbonaceous-non-carbonaceous composite-coated graphite of the present invention;

도 3은 본 발명에 따른 실시예 및 비교예에 따라 제조된 음극 활물질을 포함하는 리튬 이차전지의 사이클 수에 따른 전극용량 변화를 나타낸 그래프이다.3 is a graph showing a change in electrode capacity according to the number of cycles of a lithium secondary battery including a negative electrode active material prepared according to Examples and Comparative Examples according to the present invention.

본 발명은 리튬 이차전지의 음극 활물질로 사용되기에 유용한, 탄소재-비탄소재의 복합체가 피복된 흑연 분말 및 이의 제조방법에 관한 것이다.The present invention relates to a graphite powder coated with a composite of carbon material and non-carbon material, which is useful for use as a negative electrode active material of a lithium secondary battery, and a method of manufacturing the same.

이차전지로 가장 널리 이용되는 리튬 이차전지의 음극 활물질로는 신뢰성, 전지 방전 특성, 사이클 수명 및 안전성 등의 기본적 특성을 만족시키는 재료로 알려진 흑연 재료가 일반적으로 사용되고 있다. As a negative electrode active material of a lithium secondary battery most widely used as a secondary battery, a graphite material known as a material that satisfies basic characteristics such as reliability, battery discharge characteristics, cycle life, and safety is generally used.

이러한 흑연을 사용한 리튬 2차 전지의 경우, 흑연 결정층을 형성하고 있는 탄소-탄소간 결합으로 구성된 그라펜(육각형 단위 망면, graphene) 상의 육각형 공간의 제한된 크기로 인해, 충전시 리튬이온이 그라펜 상에 따른 면인 기저면(basal plane)을 통과할 수 없어 기저면에 수직인 단면인 엣지면(edge plane)으로부터 흡장되어 흑연층간을 출입하는 특징이 있다.In the case of a lithium secondary battery using such graphite, lithium ions are graphene when charged due to the limited size of the hexagonal space on the graphene (hexagonal unit mesh, graphene) composed of carbon-carbon bonds forming the graphite crystal layer. Since it cannot pass through a basal plane, which is a plane according to the phase, it is occluded from an edge plane, which is a cross section perpendicular to the base plane, and has a feature of entering and exiting between graphite layers.

흑연의 이론적 용량 밀도는 372 mAh/g인데 이러한 이론치에 가장 근접한 고결정성 천연 흑연은 고율 충방전 및 긴 수명을 달성하는 것이 곤란한 단점이 있으며, 천연 흑연의 문제점을 해결하기 위한 기존의 합성 흑연 재료의 경우도 역시 리튬을 전기 화학적으로 흡장하는 경우 결정의 층간 간격이 최대 10% 확대되어 층간 결합이 느슨해지고 그 결과 충방전을 반복하고 있는 동안 점차 층간 박리가 생겨, 전지 성능의 열화를 초래하는 문제점이 있다. The theoretical capacity density of graphite is 372 mAh / g, and the high crystalline natural graphite closest to this theory has a disadvantage in that it is difficult to achieve high rate charging and discharging and long life, and to solve the problems of natural graphite. In some cases, when lithium is electrochemically occluded, the interlayer spacing of crystals is increased by up to 10%, resulting in loosening of interlayer bonds, and as a result, delamination gradually occurs during repeated charging and discharging, resulting in deterioration of battery performance. have.

이러한, 층간 박리로 인한 결정 붕괴 문제를 해결하기 위해, 흑연의 단면(엣지면)을 저온 탄소재 등으로 피복하는 방법 등이 고안되었으나, 피복 재료로 인한 리튬 흡장량의 감소, 충전 초기 비가역성의 증대, 및 음극 특성의 저하 등의 여러 문제점을 가지며, 합성 흑연 재료를 메소카본마이크로비즈(MCMB) 또는 메소카본파이바 (MCF)등의 구상체나 섬유상체의 표면을 딱딱한 불융화막으로 피복하는 방법의 경우, 합성 흑연 재료의 가격이 고가이며 에너지 밀도가 천연 흑연 결정에 미치지 못하는 결점이 있다.In order to solve the problem of crystal collapse due to the interlayer peeling, a method of coating the cross section (edge surface) of graphite with a low temperature carbon material or the like has been devised, but the amount of lithium occlusion due to the coating material is increased and the initial reversibility of charging is increased. And a variety of problems such as deterioration of the negative electrode characteristics, and a method of coating a synthetic graphite material on the surface of a spherical body or a fibrous body such as mesocarbon microbeads (MCMB) or mesocarbonfiber (MCF) with a hard incompatible film In this case, there is a disadvantage that the price of the synthetic graphite material is high and the energy density does not reach the natural graphite crystal.

상기의 문제점들을 극복하기 위한 방안으로서, 한국 특허공개 제2000-60301호 및 제2003-62541호에서는 흑연 활물질 표면에 금속산화물을 피복하여 음극 활물질로 사용하는 기술을 개시하였다. 그러나, 이 경우 서로 다른 이종 물질인 금속산화물과 흑연의 탄소성분이 약하게 결합하고 있어 리튬 이차전지의 충방전시 금속산화물이 흑연으로부터 쉽게 이탈하는 현상을 야기하여 전지 수명이 저하될 수 있다.As a way to overcome the above problems, Korean Patent Publication Nos. 2000-60301 and 2003-62541 disclose a technique of coating a metal oxide on the surface of the graphite active material to use as a negative electrode active material. However, in this case, the metal oxides of the different dissimilar materials and the carbon components of the graphite are weakly bonded, which causes the metal oxide to easily detach from the graphite during charging and discharging of the lithium secondary battery, thereby reducing battery life.

이에 본 발명자들은 예의연구한 결과, 흑연에 대한 피복물질로서 졸-겔(sol-gel) 반응으로부터 수득한 탄소재-비탄소재 복합체 겔을 사용하는 경우 반복적인 충방전시에 일어날 수 있는 흑연으로부터 피복물질의 이탈 현상을 방지할 수 있음을 발견하고, 본 발명을 완성하게 되었다.Thus, the inventors have studied diligently to coat the graphite from carbonaceous non-carbonaceous composite gel obtained from the sol-gel reaction as a coating material for the graphite, which may occur during repeated charging and discharging. The present inventors have found that the separation of materials can be prevented and the present invention has been completed.

본 발명의 목적은 리튬 이차전지의 충방전시 발생하는 층간 간격 확대로 인한 탄소 분말의 팽창, 극판으로부터 활물질 성분들의 이탈 및 균열 등을 억제하여 전지의 용량 및 수명을 현저히 향상시킬 수 있는, 리튬 이차전지용 음극 활물질 및 이의 제조방법을 제공하는 것이다.Disclosure of Invention An object of the present invention is to suppress the expansion of carbon powder due to the expansion of the interlayer spacing generated during charging and discharging of a lithium secondary battery, the separation and cracking of active material components from the electrode plate, and the like, thereby significantly improving the capacity and life of the battery. It is to provide a negative electrode active material for a battery and a method of manufacturing the same.

상기의 목적에 따라, 본 발명에서는 흑연 분말 표면에 탄소-비탄소 성분의 복합 구조의 피복층이 형성된, 리튬 이차전지용 음극 활물질을 제공한다.In accordance with the above object, the present invention provides a negative electrode active material for a lithium secondary battery, wherein a coating layer having a carbon-non-carbon composite structure is formed on the graphite powder surface.

또한, 본 발명에서는 상기 리튬 이차전지용 음극 활물질의 제조방법으로서,In addition, in the present invention, as a method of manufacturing the negative electrode active material for a lithium secondary battery,

1) 유기 용매에 탄소재를 교반하에 용해시켜 졸 용액을 얻는 단계;1) dissolving the carbonaceous material in an organic solvent under stirring to obtain a sol solution;

2) 상온에서 고체로 존재하는 주기율표상의 비탄소 성분 함유 물질을 상기 졸 용액에 첨가한 다음, 알칼리성 물질을 첨가한 후 교반하여 겔 용액을 수득하는 단계;2) adding a non-carbon component-containing material on the periodic table present as a solid at room temperature to the sol solution, and then adding an alkaline substance followed by stirring to obtain a gel solution;

3) 상기 겔 용액에 흑연 분말을 투입한 후 교반하여 흑연 분말의 표면상에 탄소재-비탄소재의 복합체 겔 피복층을 형성하는 단계; 및3) adding graphite powder to the gel solution, followed by stirring to form a composite gel coating layer of carbon material and non-carbon material on the surface of the graphite powder; And

4) 상기 피복된 흑연 분말을 건조 및 소성하는 단계를 포함하는 방법을 제공한다.4) providing a method comprising drying and calcining the coated graphite powder.

이하, 본 발명을 상세히 설명한다.Hereinafter, the present invention will be described in detail.

본 발명의 리튬 이차전지용 음극 활물질은 도 1에 도시된 바와 같이, 흑연 분말 표면에 탄소-비탄소 성분으로 된 복합구조의 피복층이 형성된 것을 특징으로 한다.As shown in FIG. 1, the lithium secondary battery negative electrode active material of the present invention is characterized in that a coating layer having a composite structure of a carbon-non-carbon component is formed on the graphite powder surface.

상기 탄소-비탄소 복합구조의 피복층은 '탄소-비탄소성 원소-산소' 또는 '탄소-산소-비탄소성 원소'의 구조일 수 있으며, 흑연 분말상에 피복시 탄소 및 산소의 화학적 결합력에 의해 흑연과의 화학적 결합을 획기적으로 개선시킬 수 있다. 이와 같은 전극 활물질간의 결합력 개선은 활물질 성분들의 이탈을 방지하여, 흑연 층간 간격 확장에 의한 층간 박리현상을 감소시키고, 전극과 전해질간에 균일한 계면(SEI, solid electrolyte interface)을 형성하여 전극-전해질의 계면특성을 향상시킬 수 있다. 따라서, 결과적으로 전지의 수명이 현저히 개선될 수 있다.The coating layer of the carbon-non-carbon composite structure may have a structure of 'carbon-non-carbon-element-oxygen' or 'carbon-oxygen-non-carbon-element' and may be coated with graphite by chemical bonding of carbon and oxygen when coated on graphite powder. Can significantly improve the chemical bonding of. The improvement of the bonding force between the electrode active materials prevents the separation of active material components, reduces the delamination caused by the graphite interlayer spacing, and forms a solid electrolyte interface (SEI) between the electrode and the electrolyte. The interface property can be improved. As a result, the life of the battery can be significantly improved.

본 발명에서, 탄소-비탄소 복합구조의 피복층은 1 내지 500 nm의 두께로 형성될 수 있다.In the present invention, the coating layer of the carbon-non-carbon composite structure may be formed to a thickness of 1 to 500 nm.

본 발명에 따른 리튬 이차전지용 음극 활물질은 특히 졸-겔(sol-gel) 반응을 통해 얻은 겔상 복합체를 이용함으로써 수득할 수 있으며, 구체적으로는 유기 용매에 탄소재를 교반하에 용해시켜 졸 용액을 얻는 다음, 상기 졸 용액에 상온에서 고체로 존재하는 주기율표상의 비탄소 성분 함유 물질 및 이어서 알칼리성 물질을 첨가한 후 교반을 통해 겔 용액을 수득하고, 여기에 흑연 분말을 투입한 다음 충분한 교반을 수행하여 흑연 분말의 표면상에 탄소재-비탄소재 복합체 겔의 피복층을 형성한 후 건조 및 소성 공정을 거침으로써 얻을 수 있다.The negative electrode active material for a lithium secondary battery according to the present invention can be obtained by using a gel composite obtained through a sol-gel reaction, in particular, to obtain a sol solution by dissolving a carbon material in an organic solvent under stirring. Next, a non-carbon component-containing substance on the periodic table and then an alkaline substance, which are present as a solid at room temperature, are added to the sol solution to obtain a gel solution through stirring, and then graphite powder is added thereto, followed by sufficient stirring. It can be obtained by forming a coating layer of the carbon-non-carbon-based composite gel on the surface of the powder and then subjecting it to drying and baking.

본 발명에서 사용가능한 탄소재는 석탄계 피치 또는 석유계 피치의 소프트카본, 또는 페놀 수지 등의 하드카본과 같은 비정질계 탄소재료를 사용하는 것이 바람직하나, 이에 국한되는 것은 아니다. 이와 같은 탄소재는 유기 용매의 중량을 기준으로 1 내지 30 중량%, 바람직하게는 3 내지 20 중량%의 양으로 사용될 때 최상의 전지 특성을 나타낼 수 있다.As the carbon material usable in the present invention, it is preferable to use an amorphous carbon material such as soft carbon of coal pitch or petroleum pitch, or hard carbon such as phenol resin, but is not limited thereto. Such carbon materials may exhibit the best battery characteristics when used in an amount of 1 to 30% by weight, preferably 3 to 20% by weight, based on the weight of the organic solvent.

또한, 본 발명에서 비탄소성 물질로는 상온에서 고체로 존재하는 주기율표상의 비탄소 원소 자체 또는 이의 산화물이 사용될 수 있으며, 그 구체적인 예로는 Na, Ca, Al, Mg, Sn, Sn, Cu, Fe, Ni, Ti, Pb, Zn, Zr, Mn, Cr, Co, Ag, Si 및 P로 이루어진 군으로부터 선택되는 하나 이상의 원소를 들 수 있다. 본 발명의 방법에서, 비탄소성 물질은 탄소재의 중량을 기준으로 0.1 내지 15 중량%의 양으로 사용되는 것이 바람직하다.In addition, as the non-carbonaceous material in the present invention, the non-carbon element itself or an oxide thereof on the periodic table existing as a solid at room temperature may be used. Specific examples thereof include Na, Ca, Al, Mg, Sn, Sn, Cu, Fe, And at least one element selected from the group consisting of Ni, Ti, Pb, Zn, Zr, Mn, Cr, Co, Ag, Si and P. In the process of the invention, the non-carbonaceous material is preferably used in an amount of 0.1 to 15% by weight based on the weight of the carbon material.

상기 졸 용액을 형성하는데 사용되는 유기 용매로는 에탄올 등의 알코올, 아세톤, 테트라하이드로퓨란, 벤젠 등이 바람직하다.As the organic solvent used to form the sol solution, alcohols such as ethanol, acetone, tetrahydrofuran, benzene and the like are preferable.

상기 겔 용액은 pH 범위가 3 내지 10 인 경우에 우수한 피복 특성 및 전지 특성을 나타낼 수 있으며, 이러한 겔 용액을 수득하는데 사용되는 알칼리성 물질로는 암모니아, 수산화칼륨, 수산화나트륨, 생석회 등이 있다.The gel solution may exhibit excellent coating properties and battery properties when the pH range is 3 to 10, and alkaline materials used to obtain such gel solutions include ammonia, potassium hydroxide, sodium hydroxide, quicklime, and the like.

본 발명에서, 흑연 분말상에 탄소-비탄소 복합구조의 피복층을 형성하기 위한 겔 용액과 흑연 분말과의 반응은 피복층이 1 내지 500nm의 두께로 형성될 때까지, 예컨대 10분 내지 3시간 동안 이루어질 수 있으며, 이때 흑연 분말로는 평균 입자 크기가 5 내지 50 ㎛인 것을 사용하는 것이 바람직하다.In the present invention, the reaction between the graphite solution and the gel solution for forming the carbon-non-carbon composite structure on the graphite powder may be performed, for example, for 10 minutes to 3 hours until the coating layer is formed to a thickness of 1 to 500 nm. In this case, as the graphite powder, an average particle size of 5 to 50 μm is preferably used.

상기 건조 공정은 80 내지 300 ℃의 온도에서 수행되어 사용된 용매를 완전히 제거하게 되며, 소성 공정은 300 내지 2000 ℃에서 수행된다.The drying process is carried out at a temperature of 80 to 300 ℃ to completely remove the solvent used, the firing process is carried out at 300 to 2000 ℃.

이렇게 하여 제조된 본 발명의 리튬 이차전지용 음극 활물질은 탄소-비탄소성 원소-산소 또는 탄소-산소-비탄소성 원소 구조의 탄소-비탄소 복합구조 피복층을 1 내지 500nm의 두께로 가져 전지의 용량 및 수명을 현저히 개선시킬 수 있다.The negative electrode active material for a lithium secondary battery of the present invention prepared as described above has a carbon-non-carbon composite structure coating layer having a carbon-non-carbonaceous element-oxygen or carbon-oxygen-non-carbonaceous element structure having a thickness of 1 to 500 nm, and thus has a capacity and lifespan. Can be significantly improved.

이하, 본 발명을 실시예에 의해 상세히 설명한다. 단, 하기 실시예는 본 발명을 예시하는 것일 뿐, 본 발명의 내용이 하기 실시예에 한정되는 것은 아니다.Hereinafter, the present invention will be described in detail by way of examples. However, the following examples are merely to illustrate the invention, but the content of the present invention is not limited to the following examples.

실시예 1Example 1

에탄올 100㎖에 탄소재 물질로서 석유계 피치 5g을 교반하에 용해시켜 졸 용액을 얻은 다음, 여기에 비탄소재 물질로서 산화알루미늄 및 제2인산암모늄 (diammonium hydrogen phosphate)를 각각 1g 및 2g 첨가하고 2시간 동안 교반시킨 후, pH 9의 겔 용액이 얻어질 때까지 암모니아를 첨가하였다. 생성된 겔 용액에 평균 입경이 20㎛인 분말 형태의 흑연 100g을 투입하여 1시간 동안 교반시킨 다음, 100℃에서 24시간 동안 건조하고, 1200℃에서 소성시켜, 탄소-AlP-산소 또는 탄소-산소-AlP가 피복된 흑연 분말을 수득하였다.5 g of petroleum pitch was dissolved in 100 ml of ethanol as a carbonaceous substance under stirring to obtain a sol solution, followed by adding 1 g and 2 g of aluminum oxide and diammonium hydrogen phosphate as non-carbonaceous substance, respectively, for 2 hours. After stirring for a while, ammonia was added until a gel solution of pH 9 was obtained. 100 g of graphite in powder form having an average particle diameter of 20 μm was added to the resulting gel solution, stirred for 1 hour, dried at 100 ° C. for 24 hours, and calcined at 1200 ° C., and then carbon-AlP-oxygen or carbon-oxygen. -AlP coated graphite powder was obtained.

상기에서 수득된 흑연 분말의 EDAX (energy dispersive X-ray analysis) 분석결과를 도 2에 나타내었다. 도 2a는 피복전 분말에 대한 것이고, 도 2b 내지 2d는 각각 흑연 분말상에 탄소-비탄소 성분 복합체의 구성원소인 O, Al 및 P가 균일하게 피복된 것을 보여주는 것으로서, 각 원소가 피복된 부분은 백색 점 형태로 나타나며 피복이 이루어지지 않은 부분은 검게 나타남을 볼 수 있다.The results of the energy dispersive X-ray analysis (EDAX) analysis of the graphite powder obtained above are shown in FIG. 2. FIG. 2A shows the pre-coating powder, and FIGS. 2B to 2D show uniform coating of O, Al and P, which are members of the carbon-non-carbon component composite, on the graphite powder, respectively. It appears in the form of dots and uncovered areas appear black.

실시예 2Example 2

탄소재 물질로서 석유계 피치 대신 페놀 수지를 사용하는 것을 제외하고는 실시예 1과 동일한 공정을 수행하여, 탄소-비탄소 성분 복합체가 피복된 흑연 분말을 수득하였다.The same process as in Example 1 was conducted except that a phenol resin was used instead of petroleum pitch as the carbonaceous material, thereby obtaining a graphite powder coated with a carbon-non-carbon component composite.

실시예 3Example 3

비탄소재 물질로서 산화알루미늄만을 사용하는 것을 제외하고는 실시예 1과 동일한 공정을 수행하여, 탄소-비탄소 성분 복합체가 피복된 흑연 분말을 수득하였다.The same process as in Example 1 was carried out except that only aluminum oxide was used as the non-carbon material, thereby obtaining a graphite powder coated with a carbon-non-carbon component composite.

실시예 4Example 4

탄소재 물질로서 석유계 피치 대신 페놀 수지를 사용하는 것을 제외하고는 실시예 3과 동일한 공정을 수행하여, 탄소-비탄소 성분 복합체가 피복된 흑연 분말을 수득하였다.The same process as in Example 3 was carried out except that a phenol resin was used instead of petroleum pitch as the carbonaceous material, thereby obtaining a graphite powder coated with a carbon-non-carbon component composite.

실시예 5Example 5

겔 용액의 pH가 3이 되도록 암모니아를 첨가하는 것을 제외하고는 실시예 1과 동일한 공정을 수행하여, 탄소-비탄소 성분 복합체가 피복된 흑연 분말을 수득하였다.The same process as in Example 1 was carried out except that ammonia was added so that the gel solution had a pH of 3, thereby obtaining a graphite powder coated with a carbon-non-carbon component composite.

실시예 6Example 6

비탄소재 물질로서 산화알루미늄만을 사용하는 것을 제외하고는 실시예 5와 동일한 공정을 수행하여, 탄소-비탄소 성분 복합체가 피복된 흑연 분말을 수득하였다.The same process as in Example 5 was carried out except that only aluminum oxide was used as the non-carbon material, thereby obtaining a graphite powder coated with a carbon-non-carbon component composite.

실시예 7Example 7

비탄소재 물질로서 산화코발트 및 제2인산암모늄을 사용하는 것을 제외하고는 실시예 1과 동일한 공정을 수행하여, 탄소-비탄소 성분 복합체가 피복된 흑연 분말을 수득하였다.The same process as in Example 1 was carried out except that cobalt oxide and ammonium diphosphate were used as the non-carbonaceous material to obtain a graphite powder coated with the carbon-non-carbon component composite.

실시예 8Example 8

탄소재 물질로서 석유계 피치 대신 페놀 수지를 사용하는 것을 제외하고는 실시예 7과 동일한 공정을 수행하여, 탄소-비탄소 성분 복합체가 피복된 흑연 분말을 수득하였다.The same process as in Example 7 was carried out except that a phenol resin was used instead of a petroleum pitch as the carbonaceous material, thereby obtaining a graphite powder coated with a carbon-non-carbon component composite.

실시예 9Example 9

암모니아 대신 수산화나트륨을 사용하는 것을 제외하고는 실시예 1과 동일한 공정을 수행하여, 탄소-비탄소 성분 복합체가 피복된 흑연 분말을 수득하였다.The same process as in Example 1 was conducted except that sodium hydroxide was used instead of ammonia to obtain graphite powder coated with a carbon-non-carbon component composite.

실시예 10Example 10

암모니아 대신 생석회를 사용하는 것을 제외하고는 실시예 1과 동일한 공정을 수행하여, 탄소-비탄소 성분 복합체가 피복된 흑연 분말을 수득하였다.Except for using quicklime instead of ammonia, the same process as in Example 1 was carried out to obtain a graphite powder coated with a carbon-non-carbon component composite.

비교예 1Comparative Example 1

에탄올에 석유계 피치를 첨가하지 않고 바로 산화알루미늄을 투입하여 용해시킨 용액에 흑연 분말을 투입하는 것을 제외하고는 실시예 1과 동일한 공정을 수행하여, 비탄소 성분만이 피복된 흑연 분말을 수득하였다.The same process as in Example 1 was carried out except that graphite powder was added to a solution in which aluminum oxide was added immediately to dissolve without adding petroleum pitch to ethanol, thereby obtaining graphite powder coated with only a non-carbon component. .

비교예 2Comparative Example 2

에탄올에 석유계 피치를 용해한 후 비탄소재 물질을 첨가하지 않고 바로 흑연 분말을 투입하는 것을 제외하고는 실시예 1과 동일한 공정을 수행하여, 탄소 성분만이 피복된 흑연 분말을 수득하였다.Except for dissolving petroleum pitch in ethanol and then immediately adding the graphite powder without adding a non-carbonaceous material, the same process as in Example 1 was carried out to obtain a graphite powder coated with only the carbon component.

시험예Test Example

상기 실시예 1 내지 10에서 얻어진 탄소-비탄소 성분의 복합구조로 피복된 흑연 분말, 비교예 1에서 얻어진 비탄소 성분-피복된 흑연 분말, 및 비교예 2에서 얻어진 탄소 성분-피복된 흑연 분말을 대상으로 리튬 이차전지용 음극 활물질로서의 전지특성을 평가하였다. The graphite powder coated with the carbon-non-carbon component composite structure obtained in Examples 1 to 10, the non-carbon component-coated graphite powder obtained in Comparative Example 1, and the carbon component-coated graphite powder obtained in Comparative Example 2 were The battery characteristics as a negative electrode active material for lithium secondary batteries were evaluated.

상기 시험재료들에 각각 카복시 메틸 셀룰로오스(CMC) 및 스타이렌 부타다이엔 고무(SBR)를 시험재료:CMC:SBR이 96:2:2의 중량비가 되도록 혼합하여 슬러리를 제조하였다. 얻어진 슬러리들을 각각 구리 호일 집전체 위에 캐스팅한 후 건조 및 압착시켜 음극 극판을 제조하였으며, 얻어진 음극, 격리막 및 리튬전극 순으로 적층한 후 리튬금속 양극을 추가 적층하여 리튬 이차전지를 제작하였다. 이때, 기준전극으로 사용되는 리튬금속과 격리막은 폴리에틸렌계 제품을 사용하였으며, 전해액은 1 몰 리튬헥사플로라이드(LiPF6)를 함유하는 에틸렌카보네이트(EC):에틸메틸카보네이트(EMC):디에틸카보네이트(DEC) 용액을 사용하였다. Each of the test materials was mixed with carboxy methyl cellulose (CMC) and styrene butadiene rubber (SBR) in a weight ratio of test material: CMC: SBR to 96: 2: 2 to prepare a slurry. The resulting slurry was cast on a copper foil current collector, and then dried and pressed to prepare a negative electrode plate. The negative electrode, the separator, and the lithium electrode were laminated in this order, and then a lithium metal positive electrode was further laminated to fabricate a lithium secondary battery. In this case, the lithium metal used as the reference electrode and the separator used a polyethylene-based product, the electrolyte solution is ethylene carbonate (EC): ethyl methyl carbonate (EMC): diethyl carbonate containing 1 mol lithium hexafluoride (LiPF 6 ) (DEC) solution was used.

상기에서 제작된 각각의 전지를 대상으로 충방전 실험을 수행하여 각 전지의 용량, 효율 및 부하를 표 1에 나타내었다.Charging and discharging experiments were performed on each of the batteries manufactured above, and the capacity, efficiency, and load of each battery are shown in Table 1.

Figure 112005071397815-PAT00001
Figure 112005071397815-PAT00001

또한, 도 3에는 각 전지의 충방전 사이클 수에 대한 용량변화, 즉 전지 수명을 나타내었다.In addition, Figure 3 shows the capacity change with respect to the number of charge and discharge cycles of each battery, that is, the battery life.

표 1 및 도 3으로부터, 본 발명에 따라 표면에 탄소 및 비탄소 성분의 복합체가 피복된 흑연 분말이 사용된 리튬 이차전지는 비교예 1 및 2의 흑연 분말이 사용된 전지에 비해 용량, 효율 및 부하에 있어서 우수할 뿐만 아니라, 안정적인 수명특성을 가짐을 알 수 있다. From Table 1 and Figure 3, according to the present invention, the lithium secondary battery using the graphite powder coated with a composite of carbon and non-carbon components on the surface compared with the capacity, efficiency and In addition to being excellent in load, it can be seen that it has a stable life characteristics.

상기에서 살펴본 바와 같이, 본 발명에 따른 리튬 이차전지용 음극 활물질은 탄소-비탄소 복합구조의 피복층을 가짐으로써 반복적인 충방전시에 일어날 수 있는 활물질 성분들의 이탈 현상을 감소시켜 전지의 용량을 현저히 개선시키고 안정된 수명특성을 나타내므로, 고에너지 밀도의 리튬 이차전지 및 휴대용 기기의 소형 또는 박형화 구현 등에 유용하게 활용될 수 있다. As described above, the negative electrode active material for a lithium secondary battery according to the present invention has a coating layer of a carbon-non-carbon composite structure, thereby reducing the phenomena of active material components that may occur during repeated charge and discharge, thereby significantly improving the battery capacity. In addition, since it exhibits a stable lifespan, it can be usefully used for miniaturization or thinning of high energy density lithium secondary batteries and portable devices.

Claims (10)

흑연 분말 표면에 탄소-비탄소 성분의 복합구조의 피복층이 형성된, 리튬 이차전지용 음극 활물질.The negative electrode active material for lithium secondary batteries in which the coating layer of the carbon-non-carbon composite structure was formed on the graphite powder surface. 제 1 항에 있어서,The method of claim 1, 탄소 성분이 석탄계 피치, 석유계 피치 및 페놀 수지로부터 선택된 비정질계 탄소재료로부터 유도된 것임을 특징으로 하는 리튬 이차전지용 음극 활물질.A negative electrode active material for a lithium secondary battery, wherein the carbon component is derived from an amorphous carbon material selected from coal pitch, petroleum pitch, and phenol resin. 제 1 항에 있어서,The method of claim 1, 비탄소 성분이 상온에서 고체로 존재하는 주기율표상의 원소 또는 이의 산화물로부터 유도된 것임을 특징으로 하는 리튬 이차전지용 음극 활물질.A negative electrode active material for a lithium secondary battery, characterized in that the non-carbon component is derived from an element on the periodic table or an oxide thereof present as a solid at room temperature. 제 3 항에 있어서,The method of claim 3, wherein 비탄소 성분이 Na, Ca, Al, Mg, Sn, Sn, Cu, Fe, Ni, Ti, Pb, Zn, Zr, Mn, Cr, Co, Ag, Si 및 P로 이루어진 군으로부터 선택되는 하나 이상의 원소인 것을 특징으로 하는 리튬 이차전지용 음극 활물질.At least one element selected from the group consisting of Na, Ca, Al, Mg, Sn, Sn, Cu, Fe, Ni, Ti, Pb, Zn, Zr, Mn, Cr, Co, Ag, Si and P The negative electrode active material for lithium secondary batteries, characterized by the above-mentioned. 1) 유기 용매에 탄소재를 교반하에 용해시켜 졸 용액을 얻는 단계;1) dissolving the carbonaceous material in an organic solvent under stirring to obtain a sol solution; 2) 상온에서 고체로 존재하는 주기율표상의 비탄소 성분 함유 물질을 상기 졸 용액에 첨가한 다음, 알칼리성 물질을 첨가한 후 교반하여 겔 용액을 수득하는 단계;2) adding a non-carbon component-containing material on the periodic table present as a solid at room temperature to the sol solution, and then adding an alkaline substance followed by stirring to obtain a gel solution; 3) 상기 겔 용액에 흑연 분말을 투입한 후 교반하여 흑연 분말의 표면상에 탄소재-비탄소재의 복합체 겔 피복층을 형성하는 단계; 및3) adding graphite powder to the gel solution, followed by stirring to form a composite gel coating layer of carbon material and non-carbon material on the surface of the graphite powder; And 4) 상기 피복된 흑연 분말을 건조 및 소성하는 단계를 포함하는, 제 1 항의 리튬 이차전지용 음극 활물질의 제조방법.4) A method of manufacturing a negative active material for a lithium secondary battery according to claim 1, comprising the step of drying and baking the coated graphite powder. 제 5 항에 있어서,The method of claim 5, 비탄소재가 탄소재의 중량을 기준으로 0.1 내지 15 중량%의 양으로 사용되는 것을 특징으로 하는 방법.Non-carbon material is used in an amount of 0.1 to 15% by weight based on the weight of the carbon material. 제 5 항에 있어서,The method of claim 5, 유기 용매가 알코올, 아세톤, 테트라하이드로퓨란 및 벤젠으로 이루어진 군으로부터 선택된 것임을 특징으로 하는 방법.The organic solvent is selected from the group consisting of alcohol, acetone, tetrahydrofuran and benzene. 제 5 항에 있어서,The method of claim 5, 알칼리성 물질이 암모니아, 수산화칼륨, 수산화나트륨, 생석회 및 이들의 혼합물로 이루어진 군으로부터 선택된 것임을 특징으로 하는 방법.And wherein the alkaline material is selected from the group consisting of ammonia, potassium hydroxide, sodium hydroxide, quicklime and mixtures thereof. 제 5 항에 있어서,The method of claim 5, 겔 용액이 3 내지 10 범위의 pH를 갖는 것을 특징으로 하는 방법.And wherein the gel solution has a pH in the range of 3 to 10. 제 1 항 내지 제 4 항 중 어느 한 항의 음극 활물질을 포함하는 리튬 이차전지.A lithium secondary battery comprising the negative electrode active material of any one of claims 1 to 4.
KR1020050118560A 2005-12-07 2005-12-07 Anode active material for lithium secondary battery having coating layer of carbon and non-carbon material and preparation thereof KR20070059569A (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101065248B1 (en) * 2010-03-04 2011-09-19 (주)포스코켐텍 Preparing Method of Anode Active Material For Lithium Secondary Battery And Lithium Secondary Battery Comprising Anode Active Material Formed Therefrom
US8205891B2 (en) 2008-09-15 2012-06-26 Stein Seal Company Intershaft seal assembly
KR101386156B1 (en) * 2012-05-08 2014-04-21 한국전기연구원 Tin Compound Based Negative Active Material, Manufacturing Method thereof And Lithium Secondary Battery Comprising The Same

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8205891B2 (en) 2008-09-15 2012-06-26 Stein Seal Company Intershaft seal assembly
KR101065248B1 (en) * 2010-03-04 2011-09-19 (주)포스코켐텍 Preparing Method of Anode Active Material For Lithium Secondary Battery And Lithium Secondary Battery Comprising Anode Active Material Formed Therefrom
KR101386156B1 (en) * 2012-05-08 2014-04-21 한국전기연구원 Tin Compound Based Negative Active Material, Manufacturing Method thereof And Lithium Secondary Battery Comprising The Same

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