WO2014119723A1 - Lithium-secondary-battery electrode and lithium secondary battery - Google Patents
Lithium-secondary-battery electrode and lithium secondary battery Download PDFInfo
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- WO2014119723A1 WO2014119723A1 PCT/JP2014/052251 JP2014052251W WO2014119723A1 WO 2014119723 A1 WO2014119723 A1 WO 2014119723A1 JP 2014052251 W JP2014052251 W JP 2014052251W WO 2014119723 A1 WO2014119723 A1 WO 2014119723A1
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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
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
- H01M4/624—Electric conductive fillers
- H01M4/625—Carbon or graphite
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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
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
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- 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
Definitions
- the present invention relates to an electrode for a lithium secondary battery using a carbon material as a conductive agent, and a lithium secondary battery using the electrode.
- a conductive agent is used for the electrode of the lithium secondary battery in order to ensure good conductivity between the active material and the current collector.
- a carbon material has been conventionally used, and among them, carbon black typified by acetylene black, carbon fiber typified by vapor grown carbon fiber, carbon nanofiber, and the like are used. When these are dispersed and distributed in the electrode, the electronic conductivity in the electrode is increased uniformly, and the reactivity of the electrode is increased.
- these conductive agents have a high tendency to agglomerate closely between the active material grains, and also adhere closely to the active material, so that they diffuse in the electrolyte that has penetrated into the gap between the active material and the conductive agent. As a result, it is difficult to increase the reactivity of the electrode, particularly the reaction of accepting lithium ions.
- Examples of using a graphene sheet as an electrode include nanographene platelets described in Patent Document 1 and hexagonal flake particles in which a plurality of nanocarbons described in Patent Document 2 are assembled.
- none of these has a structure in which the graphene sheets are bonded with a gap, and when agglomerated, it is impossible to ensure a gap in which lithium ions can easily diffuse.
- Conductive agent is much smaller than active material and has high cohesive strength. Further, in order for the electrode to maintain high electronic conductivity, the conductive agent needs to be in close contact with the active material. Therefore, in order to obtain high electronic conductivity and high lithium ion conductivity at the same time, a conductive agent having a structure capable of ensuring a gap in which lithium ions can be easily diffused even after aggregation is required.
- One embodiment of the present invention is characterized in that a plurality of single-layer or multi-layer graphene sheets are gathered in a three-dimensional manner to form a radial shape so that a gap is formed between each single-layer or multi-layer graphene sheet.
- the present invention relates to an electrode for a lithium secondary battery containing a carbon material as a conductive agent.
- a lithium secondary battery having excellent load characteristics can be obtained.
- the characteristic of the electrically conductive agent of the Example of this invention is shown, and the carbon material (right) obtained by heat-treating the carbon nanohorn aggregate (left) and the carbon nanohorn aggregate before the heat treatment is schematically illustrated.
- the parallel thick lines represent the graphene sheet of FIG.
- the characteristic of the electrically conductive agent of the Example of this invention is shown, and the characteristic of the graphene sheet of the carbon material of FIG. 1 is shown.
- the characteristics of the carbon material of the present invention are shown, and the difference from the conventional conductive agent when the carbon material of the present invention is used as a conductive agent is schematically illustrated.
- a conductive agent having a structure capable of ensuring a gap where lithium ions can be easily diffused even when agglomerated a plurality of single-layer or laminated graphene sheets are gathered three-dimensionally, and these are bonded radially.
- the carbon material is characterized in that a gap is formed between each single-layered or laminated graphene sheet.
- the gap between the single-layered or laminated graphene sheets is not completely closed, so that lithium ions are easily It is possible to secure a gap that can diffuse into Further, since the graphene sheet is radial, high electron conductivity can be ensured with a small amount.
- bonding aspect will not be specifically limited if a graphene sheet can be fixed and a clearance gap can be maintained.
- graphene sheet refers to a “single-layer graphene sheet” or a “laminated graphene sheet” having a structure in which a plurality of single-layer graphene sheets are laminated, and is a sheet laminated on each graphene sheet.
- the number is generally from 1 to 100 layers, preferably from 1 to 40 layers, more preferably from 1 to 20 layers.
- the length (long side) of each graphene sheet parallel to the graphite surface is generally 10 nm to 1 ⁇ m, preferably 10 nm to 200 nm, and the width (short side) of the surface parallel to the graphite surface. Is generally 1 nm to 1 ⁇ m, preferably 5 nm to 200 nm, and more preferably 5 nm to 100 nm.
- a method for forming such a carbon material in which a plurality of graphene sheets are three-dimensionally assembled and bonded to each other is not particularly limited.
- a carbon material such as carbon nanohorn is heat-treated, and the graphene sheets are integrated to some extent. Obtained by leaving only the wick. These graphene sheets are bonded to each other and form a strong electronic conductive network.
- Examples of the carbon material to be used as a raw material include hard carbon, soft carbon, graphite, carbon nanotube, and carbon nanohorn. Carbon nanohorn is particularly preferable, and carbon nanohorn forms an aggregate. It is preferable.
- the heat treatment conditions of the carbon material are not particularly limited, but examples include oxygen, carbon monoxide, a mixed gas of oxygen and carbon monoxide, or these gases and an inert gas, and It is performed by heating the carbon material in a mixed gas atmosphere containing one or more selected from nitrogen, and the heating temperature is generally 300 ° C. or higher, preferably 350 ° C. or higher, and preferably 2000 ° C. or lower, More preferably, it is 1000 degrees C or less.
- the carbon material of the present invention as a conductive agent, a lithium secondary battery having excellent load characteristics can be obtained.
- the electrically conductive agent of this invention can be used for the positive electrode or / and negative electrode of a lithium secondary battery, when obtaining a big effect with a small quantity, it is preferable to use for a negative electrode. By applying it to the negative electrode, a lithium secondary battery having excellent charge load characteristics can be obtained.
- the positive electrode active material of the lithium secondary battery of the present invention is not particularly limited as long as it can be used as the positive electrode active material of a lithium secondary battery.
- it has been conventionally used as a positive electrode active material.
- Li-containing transition metal oxides such as LiCoO 2 , LiNiO 2 , LiMn 2 O 4 , LiMnO 2 , LiMn 0.5 Ni 0.5 O 2 , LiNi 0.7 Co 0.2 Mn 0.1 O 2
- Examples include metal oxides such as MnO 2 that do not contain lithium.
- any substance that electrochemically inserts and desorbs lithium can be used without limitation.
- the negative electrode active material of the lithium secondary battery of the present invention is not particularly limited as long as it can be used as the negative electrode active material of the lithium secondary battery.
- it has been conventionally used as a negative electrode active material.
- examples thereof include graphite, amorphous carbon, lithium titanate, titanium oxide, silicon and oxides and alloys thereof, germanium and alloys thereof, tin and oxides and alloys thereof, and the like.
- any substance that electrochemically inserts and desorbs lithium can be used without limitation.
- a carbon material in which a plurality of graphene sheets according to the present invention are three-dimensionally assembled and bonded to each other can be used.
- the content of the carbon material according to the present invention is not particularly limited, but is preferably 0.1% by weight or more and 20% by weight or less, and more preferably 1% by weight or more and 10% by weight or less based on the active material. .
- a conductive agent different from the carbon material can be further used as necessary. These conductive agents are not particularly limited as long as they can be conventionally used as conductive agents for lithium secondary batteries.
- carbonaceous fine particles such as graphite, carbon black, and acetylene black
- carbon nanotubes examples thereof include carbon fibers such as polyaniline, conductive polymers such as polypyrrole, polythiophene, polyacetylene, and polyacene.
- the current collector of the lithium secondary battery of the present invention is not particularly limited as long as it is formed from a metal that does not alloy with lithium.
- a metal that does not alloy with lithium For example, aluminum that has been conventionally used as a positive electrode current collector, and a negative electrode current collector Examples include copper and alloys thereof, nickel, and the like.
- the solvent of the non-aqueous electrolyte used in the lithium secondary battery of the present invention is not particularly limited, but cyclic carbonates such as ethylene carbonate, propylene carbonate, butylene carbonate, vinylene carbonate, dimethyl carbonate, methyl ethyl carbonate, diethyl
- cyclic carbonates such as ethylene carbonate, propylene carbonate, butylene carbonate, vinylene carbonate, dimethyl carbonate, methyl ethyl carbonate, diethyl
- a mixed solvent with a chain carbonate such as carbonate is exemplified.
- mixed solvents of the above cyclic carbonates and ether solvents such as 1,2-dimethoxyethane and 1,2-diethoxyethane are also exemplified.
- LiPF 6 , LiBF 4 , LiCF 3 SO 3 , LiN (CF 3 SO 2 ) 2 , LiN (C 2 F 5 SO 2 ) 2 , LiN (CF 3 SO 2 ) (C 4 F 9 SO 2), LiC (CF 3 SO 2) 3, LiC (C 2 F 5 SO 2) 3, LiAsF 6, LiClO 4, Li 2 B 10 Cl 10, Li 2 B 12 Cl 12 and the like and their Mixtures are exemplified.
- examples of the electrolyte include gel polymer electrolytes in which a polymer electrolyte such as polyethylene oxide and polyacrylonitrile is impregnated with an electrolytic solution, and inorganic solid electrolytes such as LiI and Li 3 N.
- the method for producing the electrode of the present invention is not particularly limited, and a method appropriately selected according to the electrode material to be used can be used.
- a solvent is added to and mixed with an electrode active material, a conductive agent, a binder, and the like to prepare a slurry, which is applied to an electrode current collector, and an electrode is prepared by volatilizing the solvent under heating or at room temperature.
- Method for producing lithium secondary battery It does not specifically limit as a manufacturing method of the lithium secondary battery of this invention, The method suitably selected according to material can be used. For example, it is a method in which the produced electrode is stacked or wound with a separator sandwiched between and wrapped with an exterior body, and an electrolyte is injected and sealed.
- the shape of the lithium secondary battery of the present invention is not particularly limited, and a conventionally known one can be used.
- Examples of the shape of the secondary battery include an electrode laminate or a wound body sealed with a metal case, a resin case, or a laminate film made of a metal foil such as an aluminum foil and a synthetic resin film, etc. A mold, a square, a coin, a sheet, and the like are manufactured, but the present invention is not limited to these.
- a conventionally known method can be used as a method for manufacturing a secondary battery.
- Example 1 Carbon nanohorn (manufactured by NEC) was heat-treated at 600 ° C. for 1 hour in a dry air atmosphere to obtain a conductive agent.
- the characteristics of the conductive agent before and after the heat treatment are shown in FIGS.
- the graphene sheets were disordered and aggregated, and there were almost no gaps between the graphene sheets, but after the heat treatment, the relatively grown graphene sheets were bonded together and remained radially, A gap was formed between the sheets. Further, as shown in FIG.
- each graphene sheet had a length and width in a direction parallel to the sheet of about 200 nm or less, and the number of sheets laminated on each graphene sheet was about 20 layers or less.
- a slurry in which N-methylpyrrolidone is used as a dispersion medium and graphite, carbon nanohorn heat-treating conductive agent, and binder (PVdF) are mixed in a ratio of 92: 4: 4 is prepared on a copper foil by a doctor blade method. And dried to obtain a negative electrode.
- Example 1 A negative electrode was produced in the same manner as in Example 1 except that carbon nanohorn without heat treatment was used as the conductive agent.
- Example 2 A negative electrode was produced in the same manner as in Example 1 except that acetylene black was used as the conductive agent.
- LiPF 6 was dissolved in a solvent in which ethylene carbonate and diethyl carbonate were mixed at a volume ratio of 3: 7 so as to be 1 mol / liter to prepare an electrolytic solution.
- the positive electrode is cut to a size of 2 cm ⁇ 2 cm and the negative electrode is cut to a size of 2.5 cm ⁇ 2.5 cm, and the positive electrode and the negative electrode are overlapped with a separator so that the active material application surfaces face each other, and inserted into an aluminum laminate outer package And the said electrolyte solution was inject
Abstract
A carbon material characterized in that a plurality of single-layer or multi-layer graphite sheets are aggregated three dimensionally in a radial pattern such that gaps are formed therebetween is used as a conductive agent. The present invention makes it possible to provide a lithium secondary battery that exhibits excellent load characteristics.
Description
本発明は、炭素材料を導電剤として用いたリチウム二次電池用電極、およびその電極を用いたリチウム二次電池に関するものである。
The present invention relates to an electrode for a lithium secondary battery using a carbon material as a conductive agent, and a lithium secondary battery using the electrode.
リチウム二次電池の電極には、活物質と集電体間の良好な導電性を確保するために導電剤が使用される。このような導電剤として、従来より炭素材料が用いられ、中でもアセチレンブラックに代表されるカーボンブラックや、気相法炭素繊維やカーボンナノファイバーなどに代表される炭素繊維が用いられる。これらが電極内で分散して分布すると、電極内の電子導電性が均一に高まり、電極の反応性が高まる。
A conductive agent is used for the electrode of the lithium secondary battery in order to ensure good conductivity between the active material and the current collector. As such a conductive agent, a carbon material has been conventionally used, and among them, carbon black typified by acetylene black, carbon fiber typified by vapor grown carbon fiber, carbon nanofiber, and the like are used. When these are dispersed and distributed in the electrode, the electronic conductivity in the electrode is increased uniformly, and the reactivity of the electrode is increased.
しかし一方で、これらの導電剤は活物質の粒間に密に凝集する傾向が高く、さらには活物質とも密着しているために、活物質と導電剤の隙間にしみ込んだ電解液中を拡散するリチウムイオンの動きが阻害され、その結果電極の反応性、特にリチウムイオンを受け入れる反応を高めることが困難であった。
However, on the other hand, these conductive agents have a high tendency to agglomerate closely between the active material grains, and also adhere closely to the active material, so that they diffuse in the electrolyte that has penetrated into the gap between the active material and the conductive agent. As a result, it is difficult to increase the reactivity of the electrode, particularly the reaction of accepting lithium ions.
グラフェンシートを電極に用いた例としては、特許文献１に記載のナノグラフェンプレートレット、特許文献２に記載の複数のナノカーボンが集合した六角形薄片粒子などが挙げられる。しかしこれらはいずれもグラフェンシート同士が隙間をもって結合した構造を有しておらず、凝集した場合にリチウムイオンが容易に拡散できる隙間を確保することができない。
Examples of using a graphene sheet as an electrode include nanographene platelets described in Patent Document 1 and hexagonal flake particles in which a plurality of nanocarbons described in Patent Document 2 are assembled. However, none of these has a structure in which the graphene sheets are bonded with a gap, and when agglomerated, it is impossible to ensure a gap in which lithium ions can easily diffuse.
導電剤は活物質に比べ非常に小さく、凝集力が高い。また電極が高い電子導電性を維持するために、導電剤は活物質と密着する必要がある。従って高い電子導電性と高いリチウムイオン導電性を同時に得るには、凝集してもリチウムイオンが容易に拡散できる隙間を確保できる構造の導電剤が求められる。
Conductive agent is much smaller than active material and has high cohesive strength. Further, in order for the electrode to maintain high electronic conductivity, the conductive agent needs to be in close contact with the active material. Therefore, in order to obtain high electronic conductivity and high lithium ion conductivity at the same time, a conductive agent having a structure capable of ensuring a gap in which lithium ions can be easily diffused even after aggregation is required.
本発明の一態様は、複数の単層または積層グラフェンシートが３次元的に集合して放射状になることで、各々の単層または積層グラフェンシート間に隙間が形成されていることを特徴とする炭素材料を導電剤として含有するリチウム二次電池用電極に関する。
One embodiment of the present invention is characterized in that a plurality of single-layer or multi-layer graphene sheets are gathered in a three-dimensional manner to form a radial shape so that a gap is formed between each single-layer or multi-layer graphene sheet. The present invention relates to an electrode for a lithium secondary battery containing a carbon material as a conductive agent.
本発明によれば、負荷特性に優れたリチウム二次電池が得られる。
According to the present invention, a lithium secondary battery having excellent load characteristics can be obtained.
本発明は、凝集してもリチウムイオンが容易に拡散できる隙間を確保できる構造をもつ導電剤として、複数の単層または積層グラフェンシートが３次元的に集合し、それらが放射状に結合することにより、各々の単層または積層グラフェンシート間に隙間の形成された炭素材料を用いることを特徴としている。このような炭素材料を導電剤として用いた場合、図３に示すように、電極内で凝集しても単層または積層グラフェンシート間の隙間が完全に閉ざされることがないため、リチウムイオンが容易に拡散できる隙間を確保できる。またグラフェンシートが放射状になっているため、少量で高い電子導電性を確保することができる。なお、結合の態様は、グラフェンシートを固定して隙間を維持することができるものであれば、特に限定されない。
In the present invention, as a conductive agent having a structure capable of ensuring a gap where lithium ions can be easily diffused even when agglomerated, a plurality of single-layer or laminated graphene sheets are gathered three-dimensionally, and these are bonded radially. The carbon material is characterized in that a gap is formed between each single-layered or laminated graphene sheet. When such a carbon material is used as a conductive agent, as shown in FIG. 3, even when agglomerating in the electrode, the gap between the single-layered or laminated graphene sheets is not completely closed, so that lithium ions are easily It is possible to secure a gap that can diffuse into Further, since the graphene sheet is radial, high electron conductivity can be ensured with a small amount. In addition, the coupling | bonding aspect will not be specifically limited if a graphene sheet can be fixed and a clearance gap can be maintained.
また、本発明において用語「グラフェンシート」は、「単層グラフェンシート」、または、単層グラフェンシートが複数枚積層された構造の「積層グラフェンシート」を表し、各グラフェンシートに積層されたシートの数は一般に１から１００層、好ましくは１から４０層、より好ましくは１から２０層である。また、各グラフェンシートの黒鉛面に平行な面の長さ（長辺）は、一般には１０ｎｍ～１μｍであり、好ましくは１０ｎｍ～２００ｎｍであり、また黒鉛面に平行な面の幅（短辺）は、一般には１ｎｍ～１μｍであり、好ましくは５ｎｍ～２００ｎｍであり、より好ましくは５ｎｍ～１００ｎｍである。
In the present invention, the term “graphene sheet” refers to a “single-layer graphene sheet” or a “laminated graphene sheet” having a structure in which a plurality of single-layer graphene sheets are laminated, and is a sheet laminated on each graphene sheet. The number is generally from 1 to 100 layers, preferably from 1 to 40 layers, more preferably from 1 to 20 layers. Further, the length (long side) of each graphene sheet parallel to the graphite surface is generally 10 nm to 1 μm, preferably 10 nm to 200 nm, and the width (short side) of the surface parallel to the graphite surface. Is generally 1 nm to 1 μm, preferably 5 nm to 200 nm, and more preferably 5 nm to 100 nm.
このような、複数のグラフェンシートが３次元的に集合し互いに結合した炭素材料を形成する方法は特に限定されないが、例えばカーボンナノホーンなどの炭素材料を熱処理し、グラフェンシートがある程度集積された、いわば芯だけを残すことで得られる。これらのグラフェンシートは互いに結合しており、強固な電子導電ネットワークを形成している。
A method for forming such a carbon material in which a plurality of graphene sheets are three-dimensionally assembled and bonded to each other is not particularly limited. For example, a carbon material such as carbon nanohorn is heat-treated, and the graphene sheets are integrated to some extent. Obtained by leaving only the wick. These graphene sheets are bonded to each other and form a strong electronic conductive network.
ここで用いられる原料となる炭素材料としては、例として、ハードカーボン、ソフトカーボン、グラファイト、カーボンナノチューブ、カーボンナノホーンなどが挙げられるが、カーボンナノホーンが特に好ましく、カーボンナノホーンは集合体を形成していることが好ましい。
Examples of the carbon material to be used as a raw material include hard carbon, soft carbon, graphite, carbon nanotube, and carbon nanohorn. Carbon nanohorn is particularly preferable, and carbon nanohorn forms an aggregate. It is preferable.
炭素材料の熱処理条件、例えば雰囲気、加熱温度等は特に限定されるものではないが、例として、酸素、一酸化炭素、酸素と一酸化炭素の混合ガス、または、これらのガスと不活性ガスおよび窒素から選択される１つ以上とを含む混合ガス雰囲気下で炭素材料を加熱することにより行い、加熱温度は一般には３００℃以上、好ましくは３５０℃以上であり、また、好ましくは２０００℃以下、より好ましくは１０００℃以下である。
The heat treatment conditions of the carbon material, such as the atmosphere and the heating temperature, are not particularly limited, but examples include oxygen, carbon monoxide, a mixed gas of oxygen and carbon monoxide, or these gases and an inert gas, and It is performed by heating the carbon material in a mixed gas atmosphere containing one or more selected from nitrogen, and the heating temperature is generally 300 ° C. or higher, preferably 350 ° C. or higher, and preferably 2000 ° C. or lower, More preferably, it is 1000 degrees C or less.
本発明の炭素材料を導電剤として用いることにより、負荷特性に優れたリチウム二次電池が得られる。本発明の導電剤は、リチウム二次電池の正極または／および負極に用いることができるが、少量で大きな効果を得る上で負極に用いることが好ましい。負極に適用することで充電負荷特性に優れたリチウム二次電池を得ることができる。
By using the carbon material of the present invention as a conductive agent, a lithium secondary battery having excellent load characteristics can be obtained. Although the electrically conductive agent of this invention can be used for the positive electrode or / and negative electrode of a lithium secondary battery, when obtaining a big effect with a small quantity, it is preferable to use for a negative electrode. By applying it to the negative electrode, a lithium secondary battery having excellent charge load characteristics can be obtained.
［リチウム二次電池の構成および製造方法］
（正極活物質）
本発明のリチウム二次電池の正極活物質としては、リチウム二次電池の正極活物質として用いることができるものであれば特に限定されるものではなく、例えば、従来より正極活物質として用いられているＬｉＣｏＯ２、ＬｉＮｉＯ２、ＬｉＭｎ２Ｏ４、ＬｉＭｎＯ２、ＬｉＭｎ０．５Ｎｉ０．５Ｏ２、ＬｉＮｉ０．７Ｃｏ０．２Ｍｎ０．１Ｏ２などのリチウム含有遷移金属酸化物や、ＭｎＯ２などのリチウムを含有していない金属酸化物が例示される。またこの他にも、リチウムを電気化学的に挿入、脱離する物質であれば、制限なく用いることができる。 [Configuration and manufacturing method of lithium secondary battery]
(Positive electrode active material)
The positive electrode active material of the lithium secondary battery of the present invention is not particularly limited as long as it can be used as the positive electrode active material of a lithium secondary battery. For example, it has been conventionally used as a positive electrode active material. Li-containing transition metal oxides such as LiCoO 2 , LiNiO 2 , LiMn 2 O 4 , LiMnO 2 , LiMn 0.5 Ni 0.5 O 2 , LiNi 0.7 Co 0.2 Mn 0.1 O 2 , Examples include metal oxides such as MnO 2 that do not contain lithium. In addition, any substance that electrochemically inserts and desorbs lithium can be used without limitation.
（正極活物質）
本発明のリチウム二次電池の正極活物質としては、リチウム二次電池の正極活物質として用いることができるものであれば特に限定されるものではなく、例えば、従来より正極活物質として用いられているＬｉＣｏＯ２、ＬｉＮｉＯ２、ＬｉＭｎ２Ｏ４、ＬｉＭｎＯ２、ＬｉＭｎ０．５Ｎｉ０．５Ｏ２、ＬｉＮｉ０．７Ｃｏ０．２Ｍｎ０．１Ｏ２などのリチウム含有遷移金属酸化物や、ＭｎＯ２などのリチウムを含有していない金属酸化物が例示される。またこの他にも、リチウムを電気化学的に挿入、脱離する物質であれば、制限なく用いることができる。 [Configuration and manufacturing method of lithium secondary battery]
(Positive electrode active material)
The positive electrode active material of the lithium secondary battery of the present invention is not particularly limited as long as it can be used as the positive electrode active material of a lithium secondary battery. For example, it has been conventionally used as a positive electrode active material. Li-containing transition metal oxides such as LiCoO 2 , LiNiO 2 , LiMn 2 O 4 , LiMnO 2 , LiMn 0.5 Ni 0.5 O 2 , LiNi 0.7 Co 0.2 Mn 0.1 O 2 , Examples include metal oxides such as MnO 2 that do not contain lithium. In addition, any substance that electrochemically inserts and desorbs lithium can be used without limitation.
（負極活物質）
本発明のリチウム二次電池の負極活物質としては、リチウム二次電池の負極活物質として用いることができるものであれば特に限定されるものではなく、例えば、従来より負極活物質として用いられている黒鉛、非晶質炭素、チタン酸リチウム、酸化チタン、シリコンおよびその酸化物や合金、ゲルマニウムおよびその合金、スズおよびその酸化物や合金などが例示される。またこの他にも、リチウムを電気化学的に挿入、脱離する物質であれば、制限なく用いることができる。 (Negative electrode active material)
The negative electrode active material of the lithium secondary battery of the present invention is not particularly limited as long as it can be used as the negative electrode active material of the lithium secondary battery. For example, it has been conventionally used as a negative electrode active material. Examples thereof include graphite, amorphous carbon, lithium titanate, titanium oxide, silicon and oxides and alloys thereof, germanium and alloys thereof, tin and oxides and alloys thereof, and the like. In addition, any substance that electrochemically inserts and desorbs lithium can be used without limitation.
本発明のリチウム二次電池の負極活物質としては、リチウム二次電池の負極活物質として用いることができるものであれば特に限定されるものではなく、例えば、従来より負極活物質として用いられている黒鉛、非晶質炭素、チタン酸リチウム、酸化チタン、シリコンおよびその酸化物や合金、ゲルマニウムおよびその合金、スズおよびその酸化物や合金などが例示される。またこの他にも、リチウムを電気化学的に挿入、脱離する物質であれば、制限なく用いることができる。 (Negative electrode active material)
The negative electrode active material of the lithium secondary battery of the present invention is not particularly limited as long as it can be used as the negative electrode active material of the lithium secondary battery. For example, it has been conventionally used as a negative electrode active material. Examples thereof include graphite, amorphous carbon, lithium titanate, titanium oxide, silicon and oxides and alloys thereof, germanium and alloys thereof, tin and oxides and alloys thereof, and the like. In addition, any substance that electrochemically inserts and desorbs lithium can be used without limitation.
（導電剤）
本発明のリチウム二次電池の導電剤として、本発明に係る複数のグラフェンシートが３次元的に集合し互いに結合した炭素材料を用いることができる。本発明に係る炭素材料の含有量は特に限定されないが、活物質に対して０．１重量％以上２０重量％以下であることが好ましく、１重量％以上１０重量％以下であることがより好ましい。また、本発明に係る炭素材料の他に、前記炭素材料とは異なる導電剤を必要に応じてさらに用いることができる。これらの導電剤としては、従来よりリチウム二次電池の導電剤として用いることができるものであれば特に限定されるものではなく、例えば、グラファイト、カーボンブラック、アセチレンブラック等の炭素質微粒子、カーボンナノチューブ等の炭素繊維、ポリアニリン、ポリピロール、ポリチオフェン、ポリアセチレン、ポリアセン等の導電性高分子などが例示される。 (Conductive agent)
As a conductive agent of the lithium secondary battery of the present invention, a carbon material in which a plurality of graphene sheets according to the present invention are three-dimensionally assembled and bonded to each other can be used. The content of the carbon material according to the present invention is not particularly limited, but is preferably 0.1% by weight or more and 20% by weight or less, and more preferably 1% by weight or more and 10% by weight or less based on the active material. . In addition to the carbon material according to the present invention, a conductive agent different from the carbon material can be further used as necessary. These conductive agents are not particularly limited as long as they can be conventionally used as conductive agents for lithium secondary batteries. For example, carbonaceous fine particles such as graphite, carbon black, and acetylene black, carbon nanotubes Examples thereof include carbon fibers such as polyaniline, conductive polymers such as polypyrrole, polythiophene, polyacetylene, and polyacene.
本発明のリチウム二次電池の導電剤として、本発明に係る複数のグラフェンシートが３次元的に集合し互いに結合した炭素材料を用いることができる。本発明に係る炭素材料の含有量は特に限定されないが、活物質に対して０．１重量％以上２０重量％以下であることが好ましく、１重量％以上１０重量％以下であることがより好ましい。また、本発明に係る炭素材料の他に、前記炭素材料とは異なる導電剤を必要に応じてさらに用いることができる。これらの導電剤としては、従来よりリチウム二次電池の導電剤として用いることができるものであれば特に限定されるものではなく、例えば、グラファイト、カーボンブラック、アセチレンブラック等の炭素質微粒子、カーボンナノチューブ等の炭素繊維、ポリアニリン、ポリピロール、ポリチオフェン、ポリアセチレン、ポリアセン等の導電性高分子などが例示される。 (Conductive agent)
As a conductive agent of the lithium secondary battery of the present invention, a carbon material in which a plurality of graphene sheets according to the present invention are three-dimensionally assembled and bonded to each other can be used. The content of the carbon material according to the present invention is not particularly limited, but is preferably 0.1% by weight or more and 20% by weight or less, and more preferably 1% by weight or more and 10% by weight or less based on the active material. . In addition to the carbon material according to the present invention, a conductive agent different from the carbon material can be further used as necessary. These conductive agents are not particularly limited as long as they can be conventionally used as conductive agents for lithium secondary batteries. For example, carbonaceous fine particles such as graphite, carbon black, and acetylene black, carbon nanotubes Examples thereof include carbon fibers such as polyaniline, conductive polymers such as polypyrrole, polythiophene, polyacetylene, and polyacene.
（集電体）
本発明のリチウム二次電池の集電体としては、リチウムと合金化しない金属から形成されていれば特に限定されず、例えば従来より正極集電体として用いられているアルミニウム、負極集電体として用いられる銅およびその合金、ニッケルなどが挙げられる。 (Current collector)
The current collector of the lithium secondary battery of the present invention is not particularly limited as long as it is formed from a metal that does not alloy with lithium. For example, aluminum that has been conventionally used as a positive electrode current collector, and a negative electrode current collector Examples include copper and alloys thereof, nickel, and the like.
本発明のリチウム二次電池の集電体としては、リチウムと合金化しない金属から形成されていれば特に限定されず、例えば従来より正極集電体として用いられているアルミニウム、負極集電体として用いられる銅およびその合金、ニッケルなどが挙げられる。 (Current collector)
The current collector of the lithium secondary battery of the present invention is not particularly limited as long as it is formed from a metal that does not alloy with lithium. For example, aluminum that has been conventionally used as a positive electrode current collector, and a negative electrode current collector Examples include copper and alloys thereof, nickel, and the like.
（電解質）
本発明のリチウム二次電池に用いる非水電解質の溶媒は、特に限定されるものではないが、エチレンカーボネート、プロピレンカーボネート、ブチレンカーボネート、ビニレンカーボネートなどの環状カーボネートと、ジメチルカーボネート、メチルエチルカーボネート、ジエチルカーボネートなどの鎖状カーボネートとの混合溶媒が例示される。また、上記環状カーボネートと１，２－ジメトキシエタン、１，２－ジエトキシエタンなどのエーテル系溶媒との混合溶媒も例示される。また、非水電解質の溶質としては、ＬｉＰＦ６、ＬｉＢＦ４、ＬｉＣＦ３ＳＯ３、ＬｉＮ（ＣＦ３ＳＯ２)２、ＬｉＮ（Ｃ２Ｆ５ＳＯ２)２、ＬｉＮ（ＣＦ３ＳＯ２)(Ｃ４Ｆ９ＳＯ２)、ＬｉＣ（ＣＦ３ＳＯ２)３、ＬｉＣ（Ｃ２Ｆ５ＳＯ２）３、ＬｉＡｓＦ６、ＬｉＣｌＯ４、Ｌｉ２Ｂ１０Ｃｌ１０、Ｌｉ２Ｂ１２Ｃｌ１２など及びそれらの混合物が例示される。さらに電解質として、ポリエチレンオキシド、ポリアクリロニトリルなどのポリマー電解質に電解液を含浸したゲル状ポリマー電解質や、ＬｉＩ、Ｌｉ３Ｎなどの無機固体電解質が例示される。 (Electrolytes)
The solvent of the non-aqueous electrolyte used in the lithium secondary battery of the present invention is not particularly limited, but cyclic carbonates such as ethylene carbonate, propylene carbonate, butylene carbonate, vinylene carbonate, dimethyl carbonate, methyl ethyl carbonate, diethyl A mixed solvent with a chain carbonate such as carbonate is exemplified. Further, mixed solvents of the above cyclic carbonates and ether solvents such as 1,2-dimethoxyethane and 1,2-diethoxyethane are also exemplified. Moreover, as a solute of the nonaqueous electrolyte, LiPF 6 , LiBF 4 , LiCF 3 SO 3 , LiN (CF 3 SO 2 ) 2 , LiN (C 2 F 5 SO 2 ) 2 , LiN (CF 3 SO 2 ) (C 4 F 9 SO 2), LiC (CF 3 SO 2) 3, LiC (C 2 F 5 SO 2) 3, LiAsF 6, LiClO 4, Li 2B 10 Cl 10, Li 2 B 12 Cl 12 and the like and their Mixtures are exemplified. Further, examples of the electrolyte include gel polymer electrolytes in which a polymer electrolyte such as polyethylene oxide and polyacrylonitrile is impregnated with an electrolytic solution, and inorganic solid electrolytes such as LiI and Li 3 N.
本発明のリチウム二次電池に用いる非水電解質の溶媒は、特に限定されるものではないが、エチレンカーボネート、プロピレンカーボネート、ブチレンカーボネート、ビニレンカーボネートなどの環状カーボネートと、ジメチルカーボネート、メチルエチルカーボネート、ジエチルカーボネートなどの鎖状カーボネートとの混合溶媒が例示される。また、上記環状カーボネートと１，２－ジメトキシエタン、１，２－ジエトキシエタンなどのエーテル系溶媒との混合溶媒も例示される。また、非水電解質の溶質としては、ＬｉＰＦ６、ＬｉＢＦ４、ＬｉＣＦ３ＳＯ３、ＬｉＮ（ＣＦ３ＳＯ２)２、ＬｉＮ（Ｃ２Ｆ５ＳＯ２)２、ＬｉＮ（ＣＦ３ＳＯ２)(Ｃ４Ｆ９ＳＯ２)、ＬｉＣ（ＣＦ３ＳＯ２)３、ＬｉＣ（Ｃ２Ｆ５ＳＯ２）３、ＬｉＡｓＦ６、ＬｉＣｌＯ４、Ｌｉ２Ｂ１０Ｃｌ１０、Ｌｉ２Ｂ１２Ｃｌ１２など及びそれらの混合物が例示される。さらに電解質として、ポリエチレンオキシド、ポリアクリロニトリルなどのポリマー電解質に電解液を含浸したゲル状ポリマー電解質や、ＬｉＩ、Ｌｉ３Ｎなどの無機固体電解質が例示される。 (Electrolytes)
The solvent of the non-aqueous electrolyte used in the lithium secondary battery of the present invention is not particularly limited, but cyclic carbonates such as ethylene carbonate, propylene carbonate, butylene carbonate, vinylene carbonate, dimethyl carbonate, methyl ethyl carbonate, diethyl A mixed solvent with a chain carbonate such as carbonate is exemplified. Further, mixed solvents of the above cyclic carbonates and ether solvents such as 1,2-dimethoxyethane and 1,2-diethoxyethane are also exemplified. Moreover, as a solute of the nonaqueous electrolyte, LiPF 6 , LiBF 4 , LiCF 3 SO 3 , LiN (CF 3 SO 2 ) 2 , LiN (C 2 F 5 SO 2 ) 2 , LiN (CF 3 SO 2 ) (C 4 F 9 SO 2), LiC (CF 3 SO 2) 3, LiC (C 2 F 5 SO 2) 3, LiAsF 6, LiClO 4, Li 2
（電極の作製方法）
本発明の電極の作製方法としては特に限定されず、使用する電極材料に応じて適宜選択した方法を用いることができる。例えば、電極活物質、導電剤、結着剤などに溶剤を加え混合してスラリーを作製し電極集電体に塗布し、加熱下または常温で溶剤を揮発させることにより電極を作製する。 (Production method of electrode)
The method for producing the electrode of the present invention is not particularly limited, and a method appropriately selected according to the electrode material to be used can be used. For example, a solvent is added to and mixed with an electrode active material, a conductive agent, a binder, and the like to prepare a slurry, which is applied to an electrode current collector, and an electrode is prepared by volatilizing the solvent under heating or at room temperature.
本発明の電極の作製方法としては特に限定されず、使用する電極材料に応じて適宜選択した方法を用いることができる。例えば、電極活物質、導電剤、結着剤などに溶剤を加え混合してスラリーを作製し電極集電体に塗布し、加熱下または常温で溶剤を揮発させることにより電極を作製する。 (Production method of electrode)
The method for producing the electrode of the present invention is not particularly limited, and a method appropriately selected according to the electrode material to be used can be used. For example, a solvent is added to and mixed with an electrode active material, a conductive agent, a binder, and the like to prepare a slurry, which is applied to an electrode current collector, and an electrode is prepared by volatilizing the solvent under heating or at room temperature.
（リチウム二次電池の製造方法）
本発明のリチウム二次電池の製造方法としては特に限定されず、材料に応じて適宜選択した方法を用いることができる。例えば、作製した前記電極をセパレータを挟んで積層または巻回して外装体で包み、電解液を注入して封止するといった方法である。 (Method for producing lithium secondary battery)
It does not specifically limit as a manufacturing method of the lithium secondary battery of this invention, The method suitably selected according to material can be used. For example, it is a method in which the produced electrode is stacked or wound with a separator sandwiched between and wrapped with an exterior body, and an electrolyte is injected and sealed.
本発明のリチウム二次電池の製造方法としては特に限定されず、材料に応じて適宜選択した方法を用いることができる。例えば、作製した前記電極をセパレータを挟んで積層または巻回して外装体で包み、電解液を注入して封止するといった方法である。 (Method for producing lithium secondary battery)
It does not specifically limit as a manufacturing method of the lithium secondary battery of this invention, The method suitably selected according to material can be used. For example, it is a method in which the produced electrode is stacked or wound with a separator sandwiched between and wrapped with an exterior body, and an electrolyte is injected and sealed.
本発明のリチウム二次電池の形状は特に限定されず、従来公知のものを用いることができる。二次電池の形状としては、電極積層体、あるいは巻回体を金属ケース、樹脂ケース、あるいはアルミニウム箔などの金属箔と合成樹脂フィルムからなるラミネートフィルム等によって封止したもの等が挙げられ、円筒型、角型、コイン型、およびシート型等で作製されるが、本発明はこれらに限定されるものではない。また、電極からのリードの取り出し、外装等のその他の製造条件は二次電池の製造方法として従来公知の方法を用いることができる。
The shape of the lithium secondary battery of the present invention is not particularly limited, and a conventionally known one can be used. Examples of the shape of the secondary battery include an electrode laminate or a wound body sealed with a metal case, a resin case, or a laminate film made of a metal foil such as an aluminum foil and a synthetic resin film, etc. A mold, a square, a coin, a sheet, and the like are manufactured, but the present invention is not limited to these. As other manufacturing conditions such as lead extraction from the electrode and outer packaging, a conventionally known method can be used as a method for manufacturing a secondary battery.
以下、本発明を実施例に基づいてさらに詳細に説明するが、本発明は以下の実施例に何ら限定されるものではなく、その要旨を変更しない範囲において適宜変更して実施することが可能なものである。
Hereinafter, the present invention will be described in more detail based on examples. However, the present invention is not limited to the following examples, and can be implemented with appropriate modifications within a range not changing the gist thereof. Is.
（負極の作製）
（実施例１）
カーボンナノホーン（ＮＥＣ製）を乾燥空気雰囲気下で６００℃で１時間熱処理し、導電剤を得た。熱処理前後の導電剤の特徴を図１、２に示す。熱処理前のカーボンナノホーン集合体は、グラフェンシートが乱れて凝集し、グラフェンシート間の隙間もほとんどなかったが、熱処理後は、比較的成長したグラフェンシートが互いに結合して放射状に残り、各々のグラフェンシート間には隙間が形成されていた。また各々のグラフェンシートは、図２に示すように、シートに平行な方向の長さ及び幅はおよそ２００ｎｍ以下であり、各々のグラフェンシートに積層されたシート数はおよそ２０層以下であった。次にＮ－メチルピロリドンを分散媒とし、黒鉛、カーボンナノホーン熱処理導電剤、結着剤（ＰＶｄＦ）を９２：４：４の割合で混合したスラリーを作製し、これをドクターブレード法により銅箔上に塗布、乾燥して負極を得た。 (Preparation of negative electrode)
(Example 1)
Carbon nanohorn (manufactured by NEC) was heat-treated at 600 ° C. for 1 hour in a dry air atmosphere to obtain a conductive agent. The characteristics of the conductive agent before and after the heat treatment are shown in FIGS. In the carbon nanohorn aggregate before heat treatment, the graphene sheets were disordered and aggregated, and there were almost no gaps between the graphene sheets, but after the heat treatment, the relatively grown graphene sheets were bonded together and remained radially, A gap was formed between the sheets. Further, as shown in FIG. 2, each graphene sheet had a length and width in a direction parallel to the sheet of about 200 nm or less, and the number of sheets laminated on each graphene sheet was about 20 layers or less. Next, a slurry in which N-methylpyrrolidone is used as a dispersion medium and graphite, carbon nanohorn heat-treating conductive agent, and binder (PVdF) are mixed in a ratio of 92: 4: 4 is prepared on a copper foil by a doctor blade method. And dried to obtain a negative electrode.
（実施例１）
カーボンナノホーン（ＮＥＣ製）を乾燥空気雰囲気下で６００℃で１時間熱処理し、導電剤を得た。熱処理前後の導電剤の特徴を図１、２に示す。熱処理前のカーボンナノホーン集合体は、グラフェンシートが乱れて凝集し、グラフェンシート間の隙間もほとんどなかったが、熱処理後は、比較的成長したグラフェンシートが互いに結合して放射状に残り、各々のグラフェンシート間には隙間が形成されていた。また各々のグラフェンシートは、図２に示すように、シートに平行な方向の長さ及び幅はおよそ２００ｎｍ以下であり、各々のグラフェンシートに積層されたシート数はおよそ２０層以下であった。次にＮ－メチルピロリドンを分散媒とし、黒鉛、カーボンナノホーン熱処理導電剤、結着剤（ＰＶｄＦ）を９２：４：４の割合で混合したスラリーを作製し、これをドクターブレード法により銅箔上に塗布、乾燥して負極を得た。 (Preparation of negative electrode)
(Example 1)
Carbon nanohorn (manufactured by NEC) was heat-treated at 600 ° C. for 1 hour in a dry air atmosphere to obtain a conductive agent. The characteristics of the conductive agent before and after the heat treatment are shown in FIGS. In the carbon nanohorn aggregate before heat treatment, the graphene sheets were disordered and aggregated, and there were almost no gaps between the graphene sheets, but after the heat treatment, the relatively grown graphene sheets were bonded together and remained radially, A gap was formed between the sheets. Further, as shown in FIG. 2, each graphene sheet had a length and width in a direction parallel to the sheet of about 200 nm or less, and the number of sheets laminated on each graphene sheet was about 20 layers or less. Next, a slurry in which N-methylpyrrolidone is used as a dispersion medium and graphite, carbon nanohorn heat-treating conductive agent, and binder (PVdF) are mixed in a ratio of 92: 4: 4 is prepared on a copper foil by a doctor blade method. And dried to obtain a negative electrode.
（比較例１）
導電剤として、熱処理を行わないカーボンナノホーンを用いたこと以外は実施例１と同様にして負極を作製した。 (Comparative Example 1)
A negative electrode was produced in the same manner as in Example 1 except that carbon nanohorn without heat treatment was used as the conductive agent.
導電剤として、熱処理を行わないカーボンナノホーンを用いたこと以外は実施例１と同様にして負極を作製した。 (Comparative Example 1)
A negative electrode was produced in the same manner as in Example 1 except that carbon nanohorn without heat treatment was used as the conductive agent.
（比較例２）
導電剤として、アセチレンブラックを用いたこと以外は実施例１と同様にして負極を作製した。 (Comparative Example 2)
A negative electrode was produced in the same manner as in Example 1 except that acetylene black was used as the conductive agent.
導電剤として、アセチレンブラックを用いたこと以外は実施例１と同様にして負極を作製した。 (Comparative Example 2)
A negative electrode was produced in the same manner as in Example 1 except that acetylene black was used as the conductive agent.
（正極の作製）
Ｎ－メチルピロリドンを分散媒とし、ＬｉＣｏＯ２、導電剤（アセチレンブラック）、結着剤（ＰＶｄＦ）を９１：５：４の割合で混合したスラリーを作製し、これをドクターブレード法によりアルミニウム箔上に塗布、乾燥して正極を得た。 (Preparation of positive electrode)
A slurry in which N-methylpyrrolidone is used as a dispersion medium and LiCoO 2 , conductive agent (acetylene black), and binder (PVdF) are mixed at a ratio of 91: 5: 4 is prepared on an aluminum foil by a doctor blade method. And dried to obtain a positive electrode.
Ｎ－メチルピロリドンを分散媒とし、ＬｉＣｏＯ２、導電剤（アセチレンブラック）、結着剤（ＰＶｄＦ）を９１：５：４の割合で混合したスラリーを作製し、これをドクターブレード法によりアルミニウム箔上に塗布、乾燥して正極を得た。 (Preparation of positive electrode)
A slurry in which N-methylpyrrolidone is used as a dispersion medium and LiCoO 2 , conductive agent (acetylene black), and binder (PVdF) are mixed at a ratio of 91: 5: 4 is prepared on an aluminum foil by a doctor blade method. And dried to obtain a positive electrode.
（電解液の作製）
エチレンカーボネートとジエチルカーボネートを体積比３：７で混合した溶媒に、ＬｉＰＦ6を１モル／リットルとなるよう溶解させ、電解液を作製した。 (Preparation of electrolyte)
LiPF 6 was dissolved in a solvent in which ethylene carbonate and diethyl carbonate were mixed at a volume ratio of 3: 7 so as to be 1 mol / liter to prepare an electrolytic solution.
エチレンカーボネートとジエチルカーボネートを体積比３：７で混合した溶媒に、ＬｉＰＦ6を１モル／リットルとなるよう溶解させ、電解液を作製した。 (Preparation of electrolyte)
LiPF 6 was dissolved in a solvent in which ethylene carbonate and diethyl carbonate were mixed at a volume ratio of 3: 7 so as to be 1 mol / liter to prepare an electrolytic solution.
（小型ラミネートセルのサイクル試験）
前記正極を２ｃｍ×２ｃｍ、前記負極を２．５ｃｍ×２．５ｃｍの大きさに切り取り、正極および負極を活物質塗布面が対向するようにセパレータをはさんで重ね合わせ、アルミラミネート外装体に挿入し、前記電解液を注入して、小型ラミネートセルを作製した。 (Cycle test of small laminate cell)
The positive electrode is cut to a size of 2 cm × 2 cm and the negative electrode is cut to a size of 2.5 cm × 2.5 cm, and the positive electrode and the negative electrode are overlapped with a separator so that the active material application surfaces face each other, and inserted into an aluminum laminate outer package And the said electrolyte solution was inject | poured and the small laminated cell was produced.
前記正極を２ｃｍ×２ｃｍ、前記負極を２．５ｃｍ×２．５ｃｍの大きさに切り取り、正極および負極を活物質塗布面が対向するようにセパレータをはさんで重ね合わせ、アルミラミネート外装体に挿入し、前記電解液を注入して、小型ラミネートセルを作製した。 (Cycle test of small laminate cell)
The positive electrode is cut to a size of 2 cm × 2 cm and the negative electrode is cut to a size of 2.5 cm × 2.5 cm, and the positive electrode and the negative electrode are overlapped with a separator so that the active material application surfaces face each other, and inserted into an aluminum laminate outer package And the said electrolyte solution was inject | poured and the small laminated cell was produced.
２５℃にて、１ｍＡで４．２Ｖになるまで定電流充電を行い、その後１ｍＡで２．５Ｖになるまで定電流放電を行い、これを１サイクルとして３サイクル充放電を行った。次に１０ｍＡで４．２Ｖになるまで定電流充電を行い、その後１ｍＡで２．５Ｖになるまで定電流放電を行った。このとき、１０ｍＡ時の充電容量と、３サイクル目の１ｍＡ時の充電容量の比（充電負荷特性）を比較した。結果を表１に示す。
At 25 ° C., constant current charging was performed at 1 mA to 4.2 V, then constant current discharging was performed at 1 mA until 2.5 V, and this was regarded as one cycle, and three cycles of charge / discharge were performed. Next, constant current charging was performed until the voltage became 4.2 V at 10 mA, and then constant current discharging was performed until the voltage became 2.5 V at 1 mA. At this time, the ratio (charge load characteristics) of the charge capacity at 10 mA and the charge capacity at 1 mA in the third cycle was compared. The results are shown in Table 1.
表１によると、アセチレンブラックに比べ、熱処理を行わないカーボンナノホーンを負極導電剤として用いた場合の充電負荷特性が高いが、その差が小さいのに対し、カーボンナノホーン熱処理導電剤を用いた場合は大幅に上回った。これは熱処理によってグラフェンシート間の隙間が形成され、リチウムイオンが容易に拡散できる隙間を確保できたためと思われる。
According to Table 1, compared to acetylene black, the charge load characteristics when carbon nanohorns without heat treatment are used as a negative electrode conductive agent are high, but the difference is small, whereas when carbon nanohorn heat treated conductive agents are used Significantly exceeded. This is presumably because a gap between the graphene sheets was formed by the heat treatment, and a gap where lithium ions could be easily diffused was secured.
Claims (10)
- 複数の単層または積層グラフェンシートが３次元的に集合して放射状になることで、各々の単層または積層グラフェンシート間に隙間が形成されている炭素材料を含むことを特徴とするリチウム二次電池用電極。 A lithium secondary comprising a carbon material in which a plurality of single-layer or multi-layer graphene sheets are gathered three-dimensionally to be radial, and a gap is formed between each single-layer or multi-layer graphene sheet Battery electrode.
- 前記炭素材料がカーボンナノホーン集合体を熱処理することにより得られたことを特徴とする、請求項１に記載のリチウム二次電池用電極。 The electrode for a lithium secondary battery according to claim 1, wherein the carbon material is obtained by heat-treating a carbon nanohorn aggregate.
- 前記炭素材料を導電剤として含有している、請求項１または２に記載のリチウム二次電池用電極。 The electrode for a lithium secondary battery according to claim 1 or 2, wherein the carbon material is contained as a conductive agent.
- 請求項１から３のいずれか一項に記載の電極を有するリチウム二次電池。 A lithium secondary battery having the electrode according to any one of claims 1 to 3.
- 前記電極が負極である、請求項４に記載のリチウム二次電池。 The lithium secondary battery according to claim 4, wherein the electrode is a negative electrode.
- 原料炭素材料を熱処理することにより、複数の単層または積層グラフェンシートが３次元的に集合して放射状になることで各々の単層または積層グラフェンシート間に隙間が形成されている炭素材料を製造する方法。 By heat-treating the raw material carbon material, a plurality of single-layer or multilayer graphene sheets are gathered three-dimensionally to produce a carbon material in which gaps are formed between the single-layer or multilayer graphene sheets. how to.
- 前記原料炭素材料がカーボンナノホーン集合体である、請求項６に記載の炭素材料の製造方法。 The method for producing a carbon material according to claim 6, wherein the raw carbon material is a carbon nanohorn aggregate.
- 前記原料炭素材料を３５０～１０００℃で熱処理することを特徴とする、請求項６または７に記載の炭素材料の製造方法。 The method for producing a carbon material according to claim 6 or 7, wherein the raw carbon material is heat-treated at 350 to 1000 ° C.
- 前記原料炭素材料を、酸素、一酸化炭素、酸素と一酸化炭素の混合ガス、ならびにこれらのガスと不活性ガスおよび窒素から選択される１つ以上とを含む混合ガスから成る群より選択されるガス雰囲気下で熱処理することを特徴とする、請求項６から８のいずれか一項に記載の炭素材料の製造方法。 The raw carbon material is selected from the group consisting of oxygen, carbon monoxide, a mixed gas of oxygen and carbon monoxide, and a mixed gas containing these gases and one or more selected from an inert gas and nitrogen. The method for producing a carbon material according to any one of claims 6 to 8, wherein the heat treatment is performed in a gas atmosphere.
- 請求項６から９のいずれか一項に記載の製造方法により製造された前記炭素材料を導電剤として用いることを特徴とする、リチウム二次電池用電極の製造方法。 A method for producing an electrode for a lithium secondary battery, wherein the carbon material produced by the production method according to any one of claims 6 to 9 is used as a conductive agent.
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| JP2016190781A (en) * | 2015-03-30 | 2016-11-10 | 東レ株式会社 | Nanographene, nanographene-electrode active material composite particle, paste for lithium ion battery electrode, and lithium ion battery electrode |
| WO2018197903A1 (en) * | 2017-04-28 | 2018-11-01 | Zinergy Uk Limited | Battery comprising an electrode having carbon additives |
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|---|---|---|---|---|
| JP2010123437A (en) * | 2008-11-20 | 2010-06-03 | Automotive Energy Supply Corp | Lithium ion battery |
| WO2012133239A1 (en) * | 2011-03-31 | 2012-10-04 | 日本電気株式会社 | Carbon nanotube/carbon nanohorn complex, method for producing carbon nanotube/carbon nanohorn complex, and application therefor |
| JP2012214342A (en) * | 2011-03-31 | 2012-11-08 | Nec Corp | Carbon nanotube nanohorn conjugate, and manufacturing method and use of the same |
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| JP2010123437A (en) * | 2008-11-20 | 2010-06-03 | Automotive Energy Supply Corp | Lithium ion battery |
| WO2012133239A1 (en) * | 2011-03-31 | 2012-10-04 | 日本電気株式会社 | Carbon nanotube/carbon nanohorn complex, method for producing carbon nanotube/carbon nanohorn complex, and application therefor |
| JP2012214342A (en) * | 2011-03-31 | 2012-11-08 | Nec Corp | Carbon nanotube nanohorn conjugate, and manufacturing method and use of the same |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2016190781A (en) * | 2015-03-30 | 2016-11-10 | 東レ株式会社 | Nanographene, nanographene-electrode active material composite particle, paste for lithium ion battery electrode, and lithium ion battery electrode |
| WO2018197903A1 (en) * | 2017-04-28 | 2018-11-01 | Zinergy Uk Limited | Battery comprising an electrode having carbon additives |
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