KR19990004384A - A lithium battery positive electrode and its manufacturing method - Google Patents
A lithium battery positive electrode and its manufacturing method Download PDFInfo
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- KR19990004384A KR19990004384A KR1019970028474A KR19970028474A KR19990004384A KR 19990004384 A KR19990004384 A KR 19990004384A KR 1019970028474 A KR1019970028474 A KR 1019970028474A KR 19970028474 A KR19970028474 A KR 19970028474A KR 19990004384 A KR19990004384 A KR 19990004384A
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- H01M4/136—Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy
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- H01M4/64—Carriers or collectors
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- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Abstract
본 발명은 개선된 리튬 전지용 양극 및 그의 제조방법을 개시한다. 본 발명의 리튬 전지용 양극은, Li1-xAxNi1-yByO2(여기서, A = 알칼리 금속, 알칼리 토금속, B = 천이 금속, 0 ≤ x ≤ 0.1, 0 ≤ y ≤ 1.0) 또는 LiMn2-yMyO4(여기서, M=Fe, Co, Ni: 0.02 ≤ y ≤ 0.3) 또는 NbSe3, LixV2O5와 LixV6O13(여기서, 0≤ X ≤ 3.0)으로 표현되는 양극 활물질, 전자 전도성이 있는 미크론 규모의 섬유체인 첨가물, 금속 또는 탄소 재료로 이루어지는 집전체 및 활물질 입자를 집전체에 고착할 수 있는 접착제로 구성되며, 또한, 이러한 구성의 재료를 이용하여 양극용 현탁액 제조시 혹은 접착제 용액 제조시 전도성이 있는 사상체를 첨가하는 단계, 이 현탁액을 상기 집전체에 도포하는 단계를 포함하는 리튬 전지용 양극의 제조 방법이 제공된다.The present invention discloses an improved positive electrode for a lithium battery and a method of manufacturing the same. The positive electrode for a lithium battery of the present invention is Li 1-x A x Ni 1-y B y O 2 (where A = alkali metal, alkaline earth metal, B = transition metal, 0 ≤ x ≤ 0.1, 0 ≤ y ≤ 1.0) Or LiMn 2-y M y O 4 (where M = Fe, Co, Ni: 0.02 ≦ y ≦ 0.3) or NbSe 3 , Li x V 2 O 5 and Li x V 6 O 13 (where 0 ≦ X ≦ 3.0) is composed of a positive electrode active material, an additive that is a micron-scale fibrous body having electronic conductivity, a current collector made of a metal or a carbon material, and an adhesive capable of fixing the active material particles to the current collector. There is provided a method for producing a positive electrode for a lithium battery, comprising the step of adding a conductive filament in the preparation of a suspension for a positive electrode or in the preparation of an adhesive solution by applying the suspension to the current collector.
이렇게 제조된 전극은 활물질 사이에 존재하는 사상체의 망상구조로 인하여 활물질 분말과 집전체 사이의 접착력과 전기 전도도가 증진되어, 용량이 증가하고 고속 충 방전능력이 우수하며, 전극과 집전체간의 접촉강도나 전극의 기계적 성질면에서 우수한 특징을 가진다.The electrode thus manufactured has improved adhesion and electrical conductivity between the powder of the active material and the current collector due to the network structure of the filament present between the active materials, thereby increasing the capacity, excellent fast charge and discharge capacity, and the contact strength between the electrode and the current collector. B) It has excellent characteristics in terms of mechanical properties of the electrode.
Description
본 발명은 전기 전도도가 획기적으로 증가된 리튬 전지용 양극 및 그의 제조방법에 관한 것으로서, 보다 구체적으로는 전도성의 사상체(絲狀體)와 분말형 혹은 섬유형 전극 활성물질과의 복합 전극을 형성하여 이루어진 리튬 전지용 양극과 그의 제조방법에 관한 것이다.The present invention relates to a positive electrode for a lithium battery and a method of manufacturing the same, which has significantly increased electrical conductivity, and more particularly, to form a composite electrode of a conductive filament and a powdered or fibrous electrode active material. A positive electrode for a lithium battery and a manufacturing method thereof.
현재까지 개발된 리튬 전지는 방전 용량과 에너지 밀도가 높고 충방전 수명이 길다는 장점이 있는 반면, 전지의 내부 저항이 크다는 단점이 있어 왔다. 따라서 고속 방전시 전지 전압의 급격한 하강으로 인한 전지의 가(可)용량 감소가 발생하며 이 단점으로 인하여 리튬전지는 높은 전류가 요구되는 전자 기기 및 장치에서는 비효율적이다.Lithium batteries developed to date have the advantages of high discharge capacity, high energy density, and long charge / discharge lifetime, but have a disadvantage of large internal resistance of the battery. As a result, a rapid decrease in battery voltage occurs at high discharge speeds, and thus the battery capacity decreases. Due to this disadvantage, lithium batteries are inefficient in electronic devices and devices requiring high current.
상기 리튬 전지의 큰 내부 저항과 낮은 충방전 능력은 주로 전지의 양극에 의하여 야기되는데 그 원인은 종래식 양극재료와 구조의 전기 전도도가 매우 낮은데 있다. 이를 이하에 보다 구체적으로 설명한다.The large internal resistance and low charge / discharge capacity of the lithium battery are mainly caused by the battery's positive electrode, which is caused by the extremely low electrical conductivity of the conventional positive electrode material and structure. This will be described in more detail below.
일반적으로 리튬 전지의 양극은 전지 반응에 참여하는 분말형 활성물질과 탄소계 첨가제, 그리고 이들을 집전판에 고정시키는 접착제로 구성되어 있다.In general, the positive electrode of a lithium battery is composed of a powdered active material and a carbon-based additive that participates in the battery reaction, and an adhesive for fixing them to the current collector plate.
활성물질로 현재 사용되는 LiCoO2, LiMn204, LiNiO2등은 전기 전도도가 매우 좋지 않으므로 전극의 설계시 집전판으로 부터 활성물질까지의 전자 전달 통로를 부수적으로 형성해 주어야 한다. 이러한 목적으로 통상적으로 사용되어온 방법이 전도체인 카본 블랙, 흑연 등의 분말을 전극에 첨가하는 것인데, 이러한 기술은 다음의 이유에 의하여 비효율적이며 비합리적이다.LiCoO 2 , LiMn 2 0 4 , LiNiO 2, etc., which are currently used as active materials, have very poor electrical conductivity. Therefore, when designing an electrode, an electron transfer path from the current collector plate to the active material must be additionally formed. A method that has been commonly used for this purpose is to add powders such as carbon black and graphite, which are conductors, to the electrodes, which technique is inefficient and unreasonable for the following reasons.
전도성 첨가제로 사용되는 흑연과 카본 블랙의 평균 입도는 일반적으로 각각 직경 직경 1 - 20 ㎛ 와, 10 - 500 ㎚ 이다.The average particle size of graphite and carbon black used as the conductive additive is generally 1-20 μm in diameter and 10-500 nm, respectively.
이 탄소 재료들은 전기 전도도가 낮으며, 더욱이 전극 내부에서 입자들은 점접촉(point contact)에 의존하여 전기적 연결을 취하게 되는데 이로 인하여 접촉 저항에 증가하게 되고 국지적으로 고립된 입자들을 발생시킨다.These carbon materials have low electrical conductivity, and furthermore, within the electrode, the particles make electrical connections depending on point contact, which increases the contact resistance and generates locally isolated particles.
이러한 점들은 모두 전극의 저항을 증가시키고 전극의 충전 용량이 이론 값보다 저하되는 결과를 가져온다.All of these points increase the resistance of the electrode and result in the charge capacity of the electrode being lower than the theoretical value.
또한 이러한 입자들이 전도성 매트릭스의 역할을 하기 위하여는 입자와 입자끼리의 접촉이 접전판에서 부터 활성 물질 입자의 최 전단(前端)까지 부단히 이루어져야 한다.In addition, in order for these particles to function as conductive matrices, the contact between the particles and the particles must be made continuously from the contact plate to the front end of the active material particles.
상기와 같은 과정은 부작위(不作爲)적이며 통로의 형성은 순전히 입자들의 조우(遭遇) 확률에 의존하는 것으로, 상기 분말 첨가의 방법이 성공하기 위해서는 이 확률이 의미 있는 수준으로 상승되어야 하며, 종래 기술은 이 목적을 달성하기 위하여 입자의 수밀도(數密度)를 과량으로 증가시키는 방법에 의존하였다.The above process is inconsistent and the formation of passages is purely dependent on the probability of encountering the particles. In order for the method of powder addition to succeed, this probability must be raised to a meaningful level. The technique relies on a method of excessively increasing the number density of the particles to achieve this goal.
그러나 이러한 방법은, 입자가 작고 비(比)표면적이 커서 분산이 용이하지 않은 카본 블랙의 부피를 증가시킴으로써, 전극 제조시 균일하게 균일하게 분산된 슬러리를 제조하기 힘든 기술적 어려움을 야기시킨다.However, this method increases the volume of carbon black, which is small in particle size and has a large specific surface area, which is not easily dispersed, thereby causing technical difficulties in preparing a uniformly dispersed slurry in electrode production.
또한 입자의 점 접촉(point contact)에 의한 전자 통로의 저항은 접촉 횟수에 비례하여 증가하므로 전자 통로가 중첩(重疊)적으로 형성이 되지 않고는 좋은 전도도를 얻을 수 없다.In addition, since the resistance of the electron passage due to the point contact of the particles increases in proportion to the number of contacts, good conductivity cannot be obtained unless the electron passages are formed in an overlapping manner.
이 또한 과량의 전도체를 첨가하게 되는 요인이 되며, 전자 전달 통로 형성에 참여하지 못한 잉여 전도체는 전극 내부의 불활성(不活性) 체적으로 남고 그 결과 전지의 용량과 에너지 밀도가 제한되며, 불필요하게 증가된 표면적으로 인하여 전지의 자가 방전 속도를 높게 하고 충전시 전해질을 전기 화학적으로 분해하므로써 궁극적으로 전지의 수명을 제한하는 요인이 된다.This also contributes to the addition of excess conductors, and excess conductors that do not participate in the formation of electron transfer paths remain inert volumes inside the electrode, consequently limiting the capacity and energy density of the cell and unnecessarily increasing. Due to the increased surface area, the self-discharge rate of the battery is increased and the electrolyte is electrochemically decomposed during charging, which ultimately limits the battery life.
구조적으로도, 입자의 접 접촉(point contact)에 의하여 접착제의 도움을 받아 위와 같이 형성된 매트릭스는 인장 강도와 비틀림 저항이 낮아서 전극의 내구성 증강에 그다지 기여하지 못한다.Structurally, the matrix formed as described above with the help of adhesive by point contact of the particles has low tensile strength and torsional resistance and thus does not contribute much to the durability enhancement of the electrode.
본 발명은 위에 설명한 종래 기술의 근본적인 결점을 해결하기 위하여 미크론 규모 섬유형의 전기 전도체를 사용하여 구성된 양극과 그의 제조방법을 제공하는 것을 목적으로 한다.It is an object of the present invention to provide a positive electrode constructed using a micron-scale fibrous electrical conductor and a method of manufacturing the same in order to solve the fundamental drawbacks of the prior art described above.
한가닥의 섬유는 그에 필적하는 직경의 분말이 일렬로 늘어선 것과 같은 효과를 보이는 동시에 단위 부피당 표면적이 작고 종축 방향으로의 전기 전도도가 분말보다 윌등히 우수하며 기계적 강도는 일렬로 늘어선 입자들의 집합과 비교할 수 없을 정도로 우수하다.A strand of fiber has the same effect as a line of powders of comparable diameters, while having a smaller surface area per unit volume, better electrical conductivity in the longitudinal direction than the powder, and mechanical strength incomparable to a set of particles lined up. As good as it is.
본 발명은 이러한 차세대 재질을 사용하여 전극 내부에 망사 구조를 의도적이고도 효율적으로 조절하여 구축할 수 있다는 점에서 독창적이며 이점은 재래 기술이 의존할 수밖에 없는 우연하고도 과도 중복적 방법과 크게 대조된다.The present invention is unique in that it is possible to intentionally and efficiently adjust and build a mesh structure inside the electrode by using such a next-generation material, and the advantages are greatly contrasted with the accidental and redundant methods in which conventional technology is inevitably dependent.
본 발명을 다음과 같이 보다 자세히 설명할 수 있다. 종경비(縱徑比, aspect ratio)가 큰 전도성의 섬유소를 혼합하면, 섬유끼리의 물리적 중첩에 의하여 유연하면서도 스스로 지탱하는(self-supporting) 구조를 형성한다.The invention can be explained in more detail as follows. Mixing conductive fibers with high aspect ratios results in a flexible, self-supporting structure due to the physical overlap of the fibers.
이 구조에 분말형 혹은 다른 형태의 활물질을 첨가하고 접촉제를 작용시키면 구조적 강도와 전도성이 크게 신장된 망상(網狀) 조직과 활성물질 분말층이 적절히 혼합된 복합 전극 구조를 얻을 수 있다.When a powder or other active material is added to this structure and a contact agent is applied, a composite electrode structure in which the network structure and the active material powder layer, which have greatly increased structural strength and conductivity, is appropriately mixed.
여기서 개개의 섬유소는 활성물질 분말이 차지하고 남은 빈 공간에 잔류함으로 전극 체적을 불필요하게 증가시키지 않는다. 본 방법으로 제조된 전극은 전기적 저항이 작고 고속 방전시 높은 용량을 보이며, 충방전을 거듭할 때 발생하는 전극 활물질의 수축 팽창이 수반하는 응력을 분산, 완충하는 특성을 보인다.In this case, the individual fibers do not unnecessarily increase the electrode volume by remaining in the remaining empty space occupied by the active material powder. The electrode manufactured by the present method has a small electrical resistance, shows a high capacity during high-speed discharge, and exhibits a property of dispersing and buffering stress accompanying shrinkage and expansion of the electrode active material generated during repeated charging and discharging.
도 1 은 사상 전도체 참가가 전극 용량에 미치는 영향을 나타내는 그래프도이다.1 is a graph showing the effect of filamentary conductor participation on electrode capacity.
전술한 목적을 달성하기 위해 제공되는 본 발명의 리튬 전지용 양극은, Li1-xAxNi1-yByO2(여기서, A = 알칼리 금속, 알칼리 토금속, B = 천이 금속, 0 ≤ x ≤ 0.1, 0 ≤ y ≤ 1.0) 또는 LiMn2-yMyO4(여기서, M=Fe, Co, Ni: 0.02 ≤ y ≤ 0.3), 또는 NbSe3, 또는 LixV2O5, LixV6O13(여기서, 0≤ X ≤ 3.0)으로 표현되는 양극 활물질, 전자 전도성이 있는 미크론 규모의 섬유체인 첨가물, 금속 또는 탄소 재료로 이루어지는 집전체, 및 활물질 입자를 집전체에 고착할 수 있는 접착제로 구성되며, 또한 이러한 구성의 재료를 이용하여 양극영 현탁액 제조시 혹은 접착제 용액 제조시 전도성이 있는 사상체를 첨가하는 단계, 이 현탁액을 상기 집전체에 도포하는 단계, 및 이 도포체를 오븐에서 가열하는 단계를 포함하는 리튬 전지용 양극의 제조 방법이 제공된다.In order to achieve the above object, the positive electrode for a lithium battery of the present invention is Li 1-x A x Ni 1-y B y O 2 (where A = alkali metal, alkaline earth metal, B = transition metal, 0 ≦ x ≤ 0.1, 0 ≤ y ≤ 1.0) or LiMn 2-y M y O 4 (wherein M = Fe, Co, Ni: 0.02 ≤ y ≤ 0.3), or NbSe 3 , or Li x V 2 O 5 , Li x A positive electrode active material represented by V 6 O 13 (where 0 ≦ X ≦ 3.0), an additive which is a micron-scale fibrous body having electronic conductivity, a current collector made of a metal or carbon material, and an active material particle capable of fixing the active material particles to the current collector Adding a conductive filament in the preparation of the anodic suspension or in the preparation of the adhesive solution using a material of this composition, applying the suspension to the current collector, and heating the applicator in an oven Provided is a method of manufacturing a positive electrode for a lithium battery comprising the steps of:
본 발명에 이용되는 사상(絲狀) 첨가제는 금속 섬유와 탄소 섬유로 분류할 수 있다.The finishing additive used for this invention can be classified into a metal fiber and a carbon fiber.
상기 금속류로는 철, 니켈, 구리, 아연, 티타늄, 알루미늄, 은, 금, 백금 등 순수 금속 및 철-크롬의 합금, 철-크롬-니켈의 합금등 통칭 스테인레스강으로 일컫는 AISI(American lron and Steel Institute)에 의하여 분류된 합금과 알루미늄-구리, 알루미늄-망간, 알루미늄-마그네슘, 알루미늄-실리콘-마그네슘 등의 알루미늄의 합금 등에 의한 섬유가 사용되며, 탄소섬유로는 인조 흑연 및 활성탄을 기초로한 섬유나 기상성장 휘스커(vapor-grown whisker)를 사용한다.The metals include pure metals such as iron, nickel, copper, zinc, titanium, aluminum, silver, gold, platinum, and alloys of iron-chromium and alloys of iron-chromium-nickel, commonly referred to as stainless steels, called AISI (American lron and Steel). Fibers based on alloys classified by the Institute and aluminum, such as aluminum-copper, aluminum-manganese, aluminum-magnesium, aluminum-silicon-magnesium, and the like, are used. As carbon fibers, fibers based on artificial graphite and activated carbon are used. Or vapor-grown whiskers.
더욱 바람직한 사상체의 직경 및 종경비는 대상이 되는 전극 활물질의 입도 분포에 따라 달라 질 수 있으나 일반적으로 직경 0.5 미크론에서 25 미크론까지, 종경비는 4 에서 2500 정도의 범위를 갖는 섬유가 적합하다.More preferred filament diameter and longitudinal ratio may vary depending on the particle size distribution of the electrode active material of interest, but in general, fibers having a diameter ranging from 0.5 micron to 25 microns and having a longitudinal ratio of about 4 to 2500 are suitable.
이러한 섬유 물질들은 그대로, 혹은 접착증가 등의 이유로 표면 처리된 상태로 사용될 수 있으며, 상기 적합한 표면 처리의 방법으로는 단순한 표면 산화 환원 반응에서 부터 유기, 혹은 고분자 화합물의 코팅을 예로 들 수있다.Such fibrous materials may be used as they are or surface treated for reasons of increased adhesion, and the suitable method of surface treatment may include coating of organic or polymeric compounds from simple surface redox reactions.
당업자는 본 발명에서 공지하는 기술에 의하여 섬유 재료 또는 그 재료의 전 처리 과정에 관계없이 섬유 강화 전극 구조를 제조할 수 있으며, 이러한 점은 본 발명이 특별히 섬유의 종류와 그 전처리에 제한되어 있지 않다는 것을 나타낸다.A person skilled in the art can manufacture the fiber reinforced electrode structure regardless of the fiber material or the pretreatment process of the material by the technique known in the present invention, which is that the present invention is not particularly limited to the kind of fiber and its pretreatment Indicates.
상기 본 발명에서 이용되는 활물질은 전술한 양극 재료중 한 종류 혹은 두가지 이상의 혼합 활물질이 사용될 수 있으나 본 발명은 활물질의 종류에 제한되지는 않는다.As the active material used in the present invention, one or two or more kinds of the above-described positive electrode materials may be used, but the present invention is not limited to the type of active material.
전극도포용 슬러리는 전도용 사상체(1차 전도용 첨가제)와 전극 활물질을 용매에 분산시키고 적절한 유기 접착제를 직접 혹은 유기 용매에 용해시킨 후 첨가하여 제조한다.The electrode coating slurry is prepared by dispersing a conductive filament (primary conductive additive) and an electrode active material in a solvent, and adding an appropriate organic adhesive directly or in an organic solvent.
이때에 전지 및 전극 제조자의 여러 가지 설계 목적에 부합하도록, 사상체 이외의 카본 블랙 또는 다른 종류의 탄소계 분말(2차 첨가제)을 혼합할 수 있으며, 상기 접착제의 종류에 제한되지는 아니하나 통상적으로 폴리비닐리덴 플루오라이드(polyvinylidene fluoride)계, PVC계, PMMA계, SBR계, SBR Latex계, PTFE(polytetrafluoroethlene)계 고분자 재료들이 사용된다.At this time, carbon black or other kinds of carbon-based powders (secondary additives) other than filamentous materials may be mixed to meet various design purposes of battery and electrode manufacturers. Polyvinylidene fluoride (polyvinylidene fluoride), PVC, PMMA, SBR, SBR Latex, PTFE (polytetrafluoroethlene) polymer materials are used.
본 발명에 사용되는 유기용매는 휘발성이며 일반적으로 전극 건조후 전극 내에는 잔류하지 않는다.The organic solvent used in the present invention is volatile and generally does not remain in the electrode after drying the electrode.
통상적으로 nmp(n-methyl-2-pyrrolidone)나 아세톤(acetone) 등을 쓸수 있으나 유기 용매의 종류가 본 발명을 제한하지는 않는다.Typically, nmp (n-methyl-2-pyrrolidone) or acetone may be used, but the type of organic solvent does not limit the present invention.
이렇게 제조한 슬러리를 집전체에 얇게 도포한 후 오븐(oven)에서 가열하여 유기용매를 증발시키고 전극을 완성하고, 필요하면 압착(roll press)에 의하여 전극의 체적을 감소시킬 수 있다.The slurry thus prepared is applied to the current collector thinly, and then heated in an oven to evaporate the organic solvent and complete the electrode. If necessary, the volume of the electrode may be reduced by a roll press.
집전체의 재료로는 금속판, 금속박, 금속 메시(mesh), 금속 거즈(gauze), 구멍뚤린 금속박, 소결된 금속 섬유 메시, 탄소지(carbon paper), 탄소판, 탄소 코팅된 금속 등의 여러 가지 형태가 가능하며, 본 발명은 집전 재료의 기하학적 구조와 원소적 조성에 구애받지 아니한다.The materials of the current collector are various forms such as metal plate, metal foil, metal mesh, metal gauze, perforated metal foil, sintered metal fiber mesh, carbon paper, carbon plate and carbon coated metal. It is possible, and the invention is not limited to the geometry and elemental composition of the current collector material.
슬러리 제조시 활성 물질과의 분산을 용이하게 하기 위해 전도용 사상체를 단독 혹은 2차 전도체 분말과 함께 미리 유기 용매에 분산시키는 전처리를 행할 수 있으며, 이때에 활물질도 같이 혼합될 수 있고, 단순한 물리적 교반 혹은 초음파 분산기 등의 방법을 사용하여 균일하게 혼합된 슬러리를 제조할 수 있다.In order to facilitate dispersion with the active material during slurry production, pretreatment may be performed in which the conductive filaments are dispersed in an organic solvent in advance or in combination with a secondary conductor powder in advance. Uniformly mixed slurry can be prepared using a method such as an ultrasonic disperser.
슬러리 제조시 전도용 사상체의 조성은 전체 질량의 0.05%에서 50%까지 혹은 전극 활물질 질량의 0.1%에서 50%까지 변화의 폭은 자유자재로 할 수 있으며, 2차 전도체 분말이 사용되어지는 경우에는 조성의 범위는 더욱 다양하며 분말 질량대 사상체 잘량의 비는 0.01:1에서 1:0.01까지 변화할 수 있다.The composition of the conductive filament during slurry production can vary from 0.05% to 50% of the total mass or from 0.1% to 50% of the mass of the electrode active material. The range of is even more varied and the ratio of powder mass to filament mass can vary from 0.01: 1 to 1: 0.01.
그러나 본 발명에 유용한 비율은 활물질 질량의 0.5%내지 20% 이내가 바림직하다.However, the ratio useful for the present invention is preferably within 0.5% to 20% of the mass of the active material.
이하 본 발명을 구체적으로 표현하는 비제한적인 여러 실시예에 대하여 설명한다.Hereinafter, various non-limiting examples that specifically express the present invention will be described.
(실시예 1)(Example 1)
PVdF를 nmp에 약 9:1의 비율로 용해시켜 접착제 용액을 준비하였다. 여기에 LiCoO2(Seimi)와 흑연(Lonza, KS6)을 첨가 혼합하여 슬러리를 제조하였다(슬러리A). 이 슬러리 A의 조성은 LiCoO2:흑연:PVdF= 91:63이다. 이 슬러리 A에 직경이 1.5㎛ 이고 길이/직경 비가 100∼1000인 스테인레스강(316L)섬유를 첨가하여 마노 모르타르(agate mortar)와 막자(pestle)로 충분히 혼합하여 슬러리를 제조하였다(슬러리 B). 이 슬러리 B에서 금속 섬유의 조성은 0%, 1%, 3%, 4%로 변화시켰다.The adhesive solution was prepared by dissolving PVdF in nmp at a ratio of about 9: 1. LiCoO 2 (Seimi) and graphite (Lonza, KS6) were added and mixed thereto to prepare a slurry (Slurry A). The composition of this slurry A is LiCoO 2 : Graphite: PVdF = 91:63. To this slurry A, stainless steel (316L) fibers having a diameter of 1.5 mu m and a length / diameter ratio of 100 to 1000 were added, and the slurry was sufficiently mixed with agate mortar and pestle (slurry B). The composition of the metal fibers in this slurry B was changed to 0%, 1%, 3%, 4%.
이렇게 제조된 슬러리 B를 니켈 메시에 도포하여 130℃에서 약 30분간 공기 건조(air-drying)하여 전극을 건조하였다.The slurry B thus prepared was applied to a nickel mesh and air-dried at 130 ° C. for about 30 minutes to dry the electrode.
위와 같이 제조된 전극을 양극으로 리튬 막박(foil)을 각각 음극과 기준 전극(Reference Electrode)으로 하고, 1M LiPF6/EC+DEC를 전해질 용액으로 사용하여 셀(cell)을 구성하였다. 조립직후 양극의 개방화로 전압은 약 3.2V 내외로 안정된 값을 보였다.The electrode manufactured as described above was used as a cathode and a lithium foil as a cathode and a reference electrode, respectively, and a cell was constructed using 1M LiPF6 / EC + DEC as an electrolyte solution. Immediately after assembly, the voltage was stable at about 3.2V due to the opening of the anode.
1/140 C 율로 셀을 충전하고 방전하여(4.2V-3.0V) 금속 섬유의 첨가가 전극의 용량에 미치는 영향을 조사하여 도 1 에 나타내었다.The cell was charged and discharged at a rate of 1/140 C (4.2 V to 3.0 V) to investigate the effect of the addition of metal fibers on the electrode capacity and is shown in FIG. 1.
또한 각 차단 전압(cut-off Voltage)에 따른 방전용량을 표 1에 정리하였다. 도 1 과 표1 의 결과는 섬유상 전도체가 첨가되었을 때 전극의 용량이 상당히 증가함을 보여준다. 이는 전극 내부에 효율적인 전자 전달통로가 형성됨으로 인함이며 이로 인하여 전극 내부에 전기적으로 고립되었던 일부 전극 활물질이 전지 반응에 참여하게 됨을 보여 준다.In addition, the discharge capacity according to each cut-off voltage is summarized in Table 1. The results in Fig. 1 and Table 1 show that the capacity of the electrode increases significantly when the fibrous conductor is added. This is due to the formation of an efficient electron transfer path inside the electrode, which shows that some electrode active material that was electrically isolated inside the electrode participates in the battery reaction.
사상 전도체 첨가제 따른 전극 용량의 변화.Variation of electrode capacity according to filamentary conductor additive
(실시예 2)(Example 2)
실시예 1 에서와 같이 제조된 슬러리B (섬유함량 4%)를 Al 박막 위에 100 미크론 두께로 도포하여 상온에서 15시간 동안 건조하고, 130℃에서 3시간, 재차 감압하여 30분동안 건조한다.Slurry B (4% fiber content) prepared as in Example 1 was applied to an Al thin film to a thickness of 100 microns and dried at room temperature for 15 hours, and then dried at reduced pressure for 3 hours at 130 ℃ for 30 minutes.
이렇게 건조된 전극을 압착하여 건조된 전극 두께의 약 80%로 두께를 감소시켜 전극을 완성하였다. 실시예 1과 같이 셀을 제작하고, 전해질은 1M LiPF6/EC+DEC를 사용하였다. 0.1C 율에서 부터 2C 율 까지 방전 속도를 변화시키면서 용량을 측정하였다(표2). 이때 충전속도는 0.1C 율로 고정하였다.This dried electrode was pressed to reduce the thickness to about 80% of the dried electrode thickness to complete the electrode. A cell was prepared as in Example 1, and 1M LiPF 6 / EC + DEC was used as the electrolyte. Capacity was measured while varying the discharge rate from 0.1C rate to 2C rate (Table 2). At this time, the charging rate was fixed at 0.1C rate.
상기 실험에서 얻은 방전 용량을 아래 표 2에 정리하였다. 고속 방전 용량이 증가하였고, 이는 전극 내부의 전기 전달 경로의 효율화에 기인한 것으로 해석할 수 있다.The discharge capacity obtained in the experiment is summarized in Table 2 below. The fast discharge capacity has increased, which can be interpreted as being due to the efficiency of the electric transfer path inside the electrode.
금속 섬유 전도체 첨가에 따른 고속방전 용량의 변화.Variation of Fast Discharge Capacity with Addition of Metal Fiber Conductor.
(실시예 3)(Example 3)
긴 섬유체의 경우 사전 분산하는 방법을 사용하였다. 엉겨 있는 상태의 스테인레스강 섬유나 Ni 섬유 뭉치를 약 0.5cm 길이로 절단하고 아세톤에 넣은 후 엉겨 있는 섬유를 호모지나이저(homogenizer)를 사용하여 충분히 풀어지도록 한 후에 사용하였다.For long fibers, pre-dispersion was used. After the tangled stainless steel fiber or Ni fiber bundle was cut to about 0.5 cm in length and placed in acetone, the entangled fiber was sufficiently released using a homogenizer before use.
이와같은 본 발명에 따른 리튬 전지용 양극은 활물질 사이에 존재하는 사상체의 망상구조로 인하여 활물질 분말과 집전체 사이의 접착력과 전기 전도도가 증진되어, 고속 충·방전 능력이 우수하며, 전극과 집전체간의 접촉강도나 전극의 기계적 성질면에서 우수한 특성을 가진다.The positive electrode for a lithium battery according to the present invention has improved adhesion and electrical conductivity between the active material powder and the current collector due to the network structure of the filamentous body present between the active material, and has excellent high-speed charging and discharging ability. It has excellent properties in terms of contact strength and mechanical properties of the electrode.
Claims (13)
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KR1019970028474A KR100368754B1 (en) | 1997-06-27 | 1997-06-27 | cathode for lithium electric cell and method of manufacturing the same |
DE69817592T DE69817592T2 (en) | 1997-06-27 | 1998-06-26 | LITHIUM-ION SECONDARY BATTERY AND METHOD FOR THE PRODUCTION THEREOF |
PCT/KR1998/000183 WO1999000001A2 (en) | 1997-06-27 | 1998-06-26 | Lithium ion secondary battery and manufacturing method of the same |
CN98807400A CN1121731C (en) | 1997-06-27 | 1998-06-26 | Lithium ion secondary battery and mfg. method of same |
JP50546399A JP4113593B2 (en) | 1997-06-27 | 1998-06-26 | Lithium ion secondary battery and manufacturing method thereof |
EP98929897A EP1016156B1 (en) | 1997-06-27 | 1998-06-26 | Lithium ion secondary battery and manufacturing method of the same |
US10/078,285 US20020168574A1 (en) | 1997-06-27 | 2002-02-15 | Lithium ion secondary battery and manufacturing method of the same |
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KR1019970028474A KR100368754B1 (en) | 1997-06-27 | 1997-06-27 | cathode for lithium electric cell and method of manufacturing the same |
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Cited By (11)
Publication number | Priority date | Publication date | Assignee | Title |
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KR100307165B1 (en) * | 1999-05-25 | 2001-09-28 | 김순택 | Positive active material composition for lithium secondary battery and lithium secondary battery comprising the same |
KR100307162B1 (en) * | 1999-05-25 | 2001-09-28 | 김순택 | Positive active material composition for lithium secondary battery and lithium secondary battery comprising the same |
KR100312689B1 (en) * | 1999-08-19 | 2001-11-03 | 김순택 | Positive active material composition for lithium secondary battery and lithium secondary battery comprising the same |
KR20040046667A (en) * | 2002-11-28 | 2004-06-05 | 삼성에스디아이 주식회사 | Positive electrode for rechargeable lithium battery and rechargeable lithium battery comprising same |
KR100496276B1 (en) * | 1998-09-29 | 2005-09-09 | 삼성에스디아이 주식회사 | Electrode binder of secondary battery and method of making active material slurry with the same |
KR100560531B1 (en) * | 1999-07-08 | 2006-03-15 | 삼성에스디아이 주식회사 | Binder for lithium secondary battery and lithium secondary battery comprising the same |
KR100714128B1 (en) * | 2005-12-08 | 2007-05-02 | 한국전자통신연구원 | Rechargeable battery having non-metallic current collector and method of manufacturing the same |
WO2009045756A2 (en) * | 2007-09-28 | 2009-04-09 | 3M Innovative Properties Company | Sintered cathode compositions |
KR20150042424A (en) * | 2013-10-11 | 2015-04-21 | 주식회사 엘지화학 | Electrode Mix of Improved Process Property and Manufacturing Method of Electrode Using the Same |
WO2021107740A1 (en) | 2019-11-29 | 2021-06-03 | 고려대학교 산학협력단 | Method for manufacturing iron-chromium oxide using ion exchange resin |
KR20210067959A (en) | 2019-11-29 | 2021-06-08 | 고려대학교 산학협력단 | Methode for iron chromate using ion-exchnage resin |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
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KR19990026736A (en) * | 1997-09-26 | 1999-04-15 | 손욱 | Cathode active materials for lithium batteries and batteries made therefrom |
KR100721035B1 (en) | 2005-07-28 | 2007-05-22 | 순천대학교 산학협력단 | Electrocatalyst of Fuel Cell, Manufacturing Method Thereof |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS63308868A (en) * | 1987-06-10 | 1988-12-16 | Hitachi Ltd | Secondary cell |
JPH0945334A (en) * | 1995-07-26 | 1997-02-14 | Katayama Tokushu Kogyo Kk | Base material for lithium secondary battery plate, electrode plate using this base material and secondary battery using this electrode plate |
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1997
- 1997-06-27 KR KR1019970028474A patent/KR100368754B1/en not_active IP Right Cessation
Cited By (13)
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KR100496276B1 (en) * | 1998-09-29 | 2005-09-09 | 삼성에스디아이 주식회사 | Electrode binder of secondary battery and method of making active material slurry with the same |
KR100307165B1 (en) * | 1999-05-25 | 2001-09-28 | 김순택 | Positive active material composition for lithium secondary battery and lithium secondary battery comprising the same |
KR100307162B1 (en) * | 1999-05-25 | 2001-09-28 | 김순택 | Positive active material composition for lithium secondary battery and lithium secondary battery comprising the same |
KR100560531B1 (en) * | 1999-07-08 | 2006-03-15 | 삼성에스디아이 주식회사 | Binder for lithium secondary battery and lithium secondary battery comprising the same |
KR100312689B1 (en) * | 1999-08-19 | 2001-11-03 | 김순택 | Positive active material composition for lithium secondary battery and lithium secondary battery comprising the same |
KR20040046667A (en) * | 2002-11-28 | 2004-06-05 | 삼성에스디아이 주식회사 | Positive electrode for rechargeable lithium battery and rechargeable lithium battery comprising same |
KR100714128B1 (en) * | 2005-12-08 | 2007-05-02 | 한국전자통신연구원 | Rechargeable battery having non-metallic current collector and method of manufacturing the same |
WO2009045756A2 (en) * | 2007-09-28 | 2009-04-09 | 3M Innovative Properties Company | Sintered cathode compositions |
WO2009045756A3 (en) * | 2007-09-28 | 2009-06-11 | 3M Innovative Properties Co | Sintered cathode compositions |
US8012624B2 (en) | 2007-09-28 | 2011-09-06 | 3M Innovative Properties Company | Sintered cathode compositions |
KR20150042424A (en) * | 2013-10-11 | 2015-04-21 | 주식회사 엘지화학 | Electrode Mix of Improved Process Property and Manufacturing Method of Electrode Using the Same |
WO2021107740A1 (en) | 2019-11-29 | 2021-06-03 | 고려대학교 산학협력단 | Method for manufacturing iron-chromium oxide using ion exchange resin |
KR20210067959A (en) | 2019-11-29 | 2021-06-08 | 고려대학교 산학협력단 | Methode for iron chromate using ion-exchnage resin |
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