JPH06212517A - Graphite fiber and its production - Google Patents
Graphite fiber and its productionInfo
- Publication number
- JPH06212517A JPH06212517A JP3164787A JP16478791A JPH06212517A JP H06212517 A JPH06212517 A JP H06212517A JP 3164787 A JP3164787 A JP 3164787A JP 16478791 A JP16478791 A JP 16478791A JP H06212517 A JPH06212517 A JP H06212517A
- Authority
- JP
- Japan
- Prior art keywords
- fiber
- graphite fiber
- graphite
- carbon fiber
- grown carbon
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- 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
- H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
- H01M4/96—Carbon-based electrodes
-
- 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
- Y02E60/30—Hydrogen technology
- Y02E60/50—Fuel cells
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は黒鉛繊維およびその製造
方法に関する。さらに詳しくは、例えば黒鉛繊維・リチ
ウム２次電池における電極活物質として、繊維強化複合
材料の形成に好適な強化材として好適な多孔性の黒鉛繊
維およびその簡単な製造方法に関する。FIELD OF THE INVENTION The present invention relates to a graphite fiber and a method for producing the same. More specifically, it relates to a porous graphite fiber suitable as a reinforcing material suitable for forming a fiber reinforced composite material, for example, as an electrode active material in a graphite fiber / lithium secondary battery, and a simple manufacturing method thereof.
【０００２】[0002]
【従来の技術および発明が解決しようとする課題】近年
の電子機器の小型化に伴って、放電容量が大きく、かつ
放電電圧が高くて安定して使用することができる小型軽
量の電池に対する要請が高まっている。そして、小型で
軽量の電池に対する要請に応えるものとして電極活物質
として黒鉛や炭素繊維を用い、電極活物質としてリチウ
ムを用いた黒鉛・リチウム２次電池の実用化が検討され
ている。2. Description of the Related Art With the recent miniaturization of electronic equipment, there is a demand for a small and lightweight battery which has a large discharge capacity and a high discharge voltage and can be used stably. It is rising. In order to meet the demand for a small and lightweight battery, practical application of a graphite / lithium secondary battery using graphite or carbon fiber as an electrode active material and lithium as an electrode active material is under study.
【０００３】その結果、電極活物質として黒鉛を使用す
る場合、放電容量を大きくすることはできる。その理由
は次のとおりと考えられている。すなわち、黒鉛・リチ
ウム２次電池の充放電に伴う反応の一例は、次式： ｎＣ＋ＣｌＯ4 -←→Ｃn ＣｌＯ4 ＋ｅ で示される。As a result, when graphite is used as the electrode active material, the discharge capacity can be increased. The reason is believed to be as follows. That is, an example of a reaction associated with charging / discharging of a graphite / lithium secondary battery is represented by the following formula: nC + ClO 4 − ← → Cn ClO 4 + e.
【０００４】上記式において、ｎの値は、いわゆる黒鉛
層間化合物の形成の程度に関係している。すなわち、黒
鉛層間化合物の形成が容易かつ良好であると、ｎの値が
小さくなって、放電容量も大きくなる。したがって、黒
鉛は、その結晶性が良好であるから、放電容量が大きく
なるのである。しかしながら、単なるグラファイト結晶
の粉末から得られる電極活物質は、実用に耐えないこと
が明らかにされた。というのは、２次電池においては充
放電を繰り返すために、電極活物質に構造的安定性が要
求されるところ、単なるグラファイト結晶の粉末は、構
造的安定性がなかったのである。In the above equation, the value of n is related to the degree of formation of so-called graphite intercalation compounds. That is, if the graphite intercalation compound is formed easily and satisfactorily, the value of n becomes small and the discharge capacity also becomes large. Therefore, since graphite has good crystallinity, the discharge capacity becomes large. However, it has been clarified that an electrode active material obtained from a simple graphite crystal powder is not practical. This is because, in the secondary battery, since the electrode active material is required to have structural stability in order to repeat charging and discharging, the mere graphite crystal powder was not structurally stable.
【０００５】したがって、構造的安定性という観点よ
り、黒鉛・リチウム２次電池の電極活物質として炭素繊
維が注目される。しかしながら、従来より検討されてき
た炭素繊維を用いた場合、前記反応式におけるｎの値が
大きくて、放電容量が小さいという問題がある。すなわ
ち、従来の炭素繊維は、ＰＡＮ（ポリアクリロニトリ
ル）の紡糸、耐炎化、炭素化等の処理またはピッチの溶
融紡糸、不融化、炭化焼成等の工程を経て製造されるも
のであり、直径５μｍ以上の連続糸である。Therefore, from the viewpoint of structural stability, attention is paid to carbon fiber as an electrode active material of a graphite / lithium secondary battery. However, when the carbon fiber which has been conventionally studied is used, there is a problem that the value of n in the above reaction formula is large and the discharge capacity is small. That is, the conventional carbon fiber is produced through processes such as PAN (polyacrylonitrile) spinning, flameproofing, carbonization, or pitch melting, spinning, infusibilization, carbonization and firing, and has a diameter of 5 μm or more. It is a continuous thread.
【０００６】また、炭素繊維は、その結晶構造が初期の
紡糸、延伸などによって大部分決定されてしまう難黒鉛
性材料であるので、たとえ２，０００℃以上の高温度で
黒鉛化処理をしたとしても容易に単結晶構造にすること
ができないのである。したがって、従来の炭素繊維で
は、構造的安定性については満足すべきものであるかも
知れないが、黒鉛層間化合物の形成が悪いので、２次電
池の電極活物質として用いた場合に十分な放電容量が得
られないという実用上の問題がある。Further, since carbon fiber is a non-graphitizable material whose crystal structure is largely determined by the initial spinning and drawing, even if it is graphitized at a high temperature of 2,000 ° C. or higher. However, it is not possible to easily form a single crystal structure. Therefore, the conventional carbon fiber may be satisfactory in terms of structural stability, but since the graphite intercalation compound is poorly formed, it has a sufficient discharge capacity when used as an electrode active material of a secondary battery. There is a practical problem that it cannot be obtained.
【０００７】一方、気相成長炭素繊維は、大きな機械的
強度を有する繊維として広く知られている。かかる優れ
た性質を有する気相成長炭素繊維を利用して、マトリッ
クスであるプラスチック、金属、セラミックス、ゴム中
に気相成長炭素繊維を分散することにより、マトリック
スの機械的特性の向上を目指した複合材料もまた良く知
られている。On the other hand, vapor grown carbon fiber is widely known as a fiber having high mechanical strength. By utilizing the vapor-grown carbon fibers having such excellent properties to disperse the vapor-grown carbon fibers in the matrix plastics, metals, ceramics, and rubbers, it is possible to improve the mechanical properties of the matrix. The materials are also well known.
【０００８】しかしながら、気相成長炭素繊維のマトリ
ックス材料に対する改善効果はその有する高い機械的特
性から予測される程、大きくはなかった。その理由とし
ては、気相成長炭素繊維は、マトリックス材料に対する
濡れ性の悪いことが指摘される。すなわち、気相成長炭
素繊維を種々のマトリックス材料に分散した複合材料を
電子顕微鏡で観察すると、マトリックス材料中に分散し
た気相成長炭素繊維は、マトリックス材料との間に微小
の間隙を有しており、あるいはそのような間隙がなくて
も単に接触しているに過ぎない状態が見られたことか
ら、上記理由が推定されるのである。その結果、マトリ
ックス材料中には気相成長炭素繊維を分散してマトリッ
クス材料を強化するといいながら、マトリックス材料中
には気相成長炭素繊維を収容した多数の空隙が存在し、
マトリックス材料と気相成長炭素繊維との間に応力の伝
達が起こらずに補強効果がないのみならず、かえってマ
トリックス材料の強度を低下させることにもなったので
ある。However, the improving effect of the vapor-grown carbon fiber on the matrix material was not so large as expected from its high mechanical properties. It is pointed out that vapor-grown carbon fibers have poor wettability with respect to the matrix material. That is, when observing a composite material in which vapor-grown carbon fibers are dispersed in various matrix materials with an electron microscope, the vapor-grown carbon fibers dispersed in the matrix material have minute gaps with the matrix material. The reason for this is presumed from the fact that a state in which there is no such gap or that there is no such gap is merely in contact. As a result, while it is said that the vapor-grown carbon fibers are dispersed in the matrix material to strengthen the matrix material, a large number of voids containing the vapor-grown carbon fibers are present in the matrix material,
Not only does the stress transfer between the matrix material and the vapor-grown carbon fiber do not occur and there is no reinforcing effect, but rather the strength of the matrix material is reduced.
【０００９】本発明は前記事情に基づいてなされたもの
である。すなわち、本発明の目的は、前記諸問題を解消
し、放電容量が大きく、しかも構造的安定性に優れた黒
鉛繊維・リチウム２次電池を製造する部材として、ある
いは、各種のマトリックス材料に対する良好な補強材と
して好適な黒鉛繊維およびその簡単な製造方法を提供す
ることにある。The present invention has been made based on the above circumstances. That is, an object of the present invention is to solve the above-mentioned problems, to be a member for producing a graphite fiber / lithium secondary battery having a large discharge capacity and excellent structural stability, or to be suitable for various matrix materials. It is to provide a graphite fiber suitable as a reinforcing material and a simple method for producing the same.
【００１０】[0010]
【前記課題を解決するための手段】前記課題を解決する
ための請求項１に記載の発明は、炭素の六角網平面が同
心円状に積層した年輪構造を有するとともに、直径が
０．００５〜２．０μｍであり、かつ多孔性であること
をことを特徴とする黒鉛繊維であり、請求項２に記載の
発明は、流動気相成長炭素繊維を２，０００℃以上の温
度で黒鉛化処理し、次いで５００〜１，１００℃の温度
で酸化処理することを特徴とする黒鉛繊維の製造方法で
あり、請求項３に記載の発明は、流動気相成長炭素繊維
を５００〜１，１００℃の温度で予め酸化処理をし、次
いで２，０００℃以上の温度で不活性気流中にて黒鉛化
処理することを特徴とする黒鉛繊維の製造方法である。The invention according to claim 1 for solving the above-mentioned problems has an annual ring structure in which carbon hexagonal planes are concentrically laminated and has a diameter of 0.005 to 2 Graphite fiber characterized by having a pore size of 0.0 μm and being porous, and the invention according to claim 2, wherein the fluidized vapor phase growth carbon fiber is graphitized at a temperature of 2,000 ° C. or higher. Then, the method for producing graphite fiber is characterized in that it is subjected to an oxidation treatment at a temperature of 500 to 1100 ° C. A method for producing graphite fiber is characterized in that it is pre-oxidized at a temperature and then graphitized in an inert gas stream at a temperature of 2,000 ° C. or higher.
【００１１】本発明の黒鉛繊維は、炭素の六角網平面が
同心円状に積層した年輪構造を有すると共に、直径が
０．００５〜２．０μｍである。ここで、黒鉛繊維の直
径が２．０μｍよりも大きくなると、例えばこの黒鉛繊
維を黒鉛繊維・リチウム２次電池の電極活物質として使
用した場合、電極反応が効率的でなくなって放電容量が
相対的に小さくなる。The graphite fiber of the present invention has an annual ring structure in which carbon hexagonal planes are concentrically laminated and has a diameter of 0.005 to 2.0 μm. Here, when the diameter of the graphite fiber is larger than 2.0 μm, for example, when the graphite fiber is used as an electrode active material of a graphite fiber / lithium secondary battery, the electrode reaction becomes inefficient and the discharge capacity becomes relatively small. Becomes smaller.
【００１２】本発明の黒鉛繊維における年輪構造は、黒
鉛化処理にもかかわらずに、原料の気相成長炭素繊維が
有する年輪構造がそのまま残存したものである。なお、
黒鉛化処理の対象になる原料繊維は、黒鉛化後における
黒鉛繊維の構造が前記年輪構造となるのであれば、前記
気相成長炭素繊維に限定されるものではない。The annual ring structure of the graphite fiber of the present invention is the one having the annual ring structure of the vapor-grown carbon fiber as a raw material as it is, despite the graphitization treatment. In addition,
The raw material fiber to be graphitized is not limited to the vapor grown carbon fiber as long as the structure of the graphite fiber after graphitization is the annual ring structure.
【００１３】もっとも、この発明において、前記流動気
相成長炭素繊維を原料繊維として特に選択するのは、前
記流動気相成長炭素繊維は、炭素の六角網平面が同心円
状に積層した年輪構造をとる易黒鉛化性繊維であり、た
とえば２８００℃以上の高熱処理によって炭素繊維の究
極物質を有する単結晶黒鉛ウイスカ−の構造とほぼ等し
くなる。そのため、黒鉛層間化合物を形成しやすく、し
たがって例えば２次電池の正極活物質として用いた場合
には、放電容量の大きい２次電池を得ることができるか
らである。In the present invention, however, the fluidized vapor phase grown carbon fiber is particularly selected as a raw material fiber because the fluidized vapor phase grown carbon fiber has an annual ring structure in which carbon hexagonal planes are concentrically laminated. It is an easily graphitizable fiber, and has a structure almost equal to that of a single crystal graphite whisker having the ultimate substance of carbon fiber, for example, by high heat treatment at 2800 ° C. or higher. Therefore, a graphite intercalation compound is easily formed, and therefore, when used as a positive electrode active material of a secondary battery, for example, a secondary battery having a large discharge capacity can be obtained.
【００１４】このような流動気相成長炭素繊維は、たと
えば、特開昭６０−５４９９８号公報に開示されたよう
に、炭素化合物と有機遷移金属化合物のガスとキャリヤ
ガスとの混合ガスを加熱することを特長とする製造方
法、特開昭６０−１８１３１９号公報に記載されたよう
に、一酸化炭素と有機遷移金属化合物のガスとキャリヤ
ガスとの混合ガスを加熱することを特長とする製造方
法、その外に特開昭６０−１８５８１８号公報、特開昭
６０−２１６８１６号公報などに記載された製造方法に
より得ることができる。Such a fluidized vapor grown carbon fiber heats a mixed gas of a carbon compound gas, an organic transition metal compound gas and a carrier gas, as disclosed in, for example, Japanese Patent Laid-Open No. 60-54998. A manufacturing method characterized by that, as described in JP-A-60-181319, a manufacturing method characterized by heating a mixed gas of carbon monoxide, a gas of an organic transition metal compound, and a carrier gas. Besides, it can be obtained by the production methods described in JP-A-60-185818 and JP-A-60-216816.
【００１５】この発明における流動気相成長炭素繊維
は、前記例示の製造方法により得られるものに限定され
ず、要するに、炭素源となる化合物を遷移金属の触媒作
用により浮遊状態で炭素繊維もしくは炭素ウイスカ−と
することができる製造方法であればどのような製造方法
によって得られるものであっても良い。この発明で興味
深いのは、流動気相成長法以外の製造方法で製造した炭
素繊維は、この発明に適用しても、この発明の目的を達
成することができないことである。The fluidized vapor grown carbon fiber in the present invention is not limited to the one obtained by the above-mentioned production method, and in short, a compound serving as a carbon source is carbon fiber or carbon whisker in a suspended state by the catalytic action of a transition metal. It may be obtained by any manufacturing method as long as it can be set to −. What is interesting in the present invention is that the carbon fibers produced by a production method other than the fluidized vapor phase growth method cannot achieve the object of the present invention even when applied to the present invention.
【００１６】たとえば、遷移金属の微粉末を基板に担持
した後で、炭化水素の熱分解によって該基板上に炭素繊
維を生成させることにより得られる基板成長炭素繊維
は、その直径が５μｍ以上である。そして、この基板成
長炭素繊維は、その軸に直交する断面に関し、年輪構造
を有しているので、層間化合物の形成に伴う（００２）
面間隔の増大に伴い、炭素六角網平面の結合に欠陥を作
らざるを得なくなる。したがって、直径が太くなるほど
炭素−炭素間の結合を切断する部分が多くなるので、層
間化合物形成のためのエネルギ−が多く必要になること
および電極反応にあずかる炭素繊維の比表面積が小さく
なって反応速度が遅くなること等により、層間化合物が
形成されにくくなる。For example, a substrate-grown carbon fiber obtained by supporting a fine powder of a transition metal on a substrate and then pyrolyzing a hydrocarbon to generate a carbon fiber on the substrate has a diameter of 5 μm or more. . The substrate-grown carbon fiber has an annual ring structure with respect to the cross section orthogonal to the axis thereof, so that it is accompanied by the formation of the intercalation compound (002).
As the interplanar spacing increases, it becomes unavoidable to make defects in the carbon hexagonal net plane bonds. Therefore, as the diameter increases, more carbon-to-carbon bonds are broken, so that more energy is required to form the intercalation compound, and the specific surface area of the carbon fiber that participates in the electrode reaction decreases and the reaction decreases. The intercalation compound is less likely to be formed due to the slower speed.
【００１７】この発明における黒鉛繊維は、特定の製造
方法すなわち流動気相成長法により製造して得られる流
動気相成長炭素繊維を黒鉛化したところの、特定の繊維
径を有すると共に多孔性の黒鉛繊維である。前記流動気
相成長炭素繊維の黒鉛化処理は、前述のように、２，０
００℃以上、好ましくは２，７００℃以上の高温に加熱
することにより行われる。The graphite fiber in the present invention has a specific fiber diameter and is porous graphite, which is obtained by graphitizing the fluidized vapor phase growth carbon fiber obtained by the specific production method, that is, the fluidized vapor phase growth method. It is a fiber. As described above, the graphitization treatment of the fluidized vapor grown carbon fiber is performed in the following manner:
It is carried out by heating to a high temperature of 00 ° C or higher, preferably 2,700 ° C or higher.
【００１８】加熱温度が２，０００℃よりも低いと、黒
鉛化が十分に達成されない。黒鉛化処理は、通常、窒
素、アルゴンなどの不活性ガスの雰囲気下に行うのが好
ましい。黒鉛化処理に要する時間は、通常、３０分で十
分である。多孔性の黒鉛繊維を得るには、黒鉛化処理の
前後のいずれかの段階で、微細孔形成処理を施すのが良
い。この微細孔形成処理により、黒鉛繊維の表面に微細
な穴が形成されると、例えばこの多孔性の黒鉛繊維を電
極活物質として使用すると、一段と充電速度が早く、且
つ放電容量が大きい２次電池を形成することができる。If the heating temperature is lower than 2,000 ° C, graphitization is not sufficiently achieved. The graphitization treatment is usually preferably performed in an atmosphere of an inert gas such as nitrogen or argon. The time required for the graphitization treatment is usually 30 minutes. In order to obtain a porous graphite fiber, it is preferable to perform the fine pore forming treatment at any stage before or after the graphitization treatment. When fine holes are formed on the surface of the graphite fiber by this fine pore forming treatment, for example, when this porous graphite fiber is used as an electrode active material, the secondary battery has a much higher charging rate and a large discharge capacity. Can be formed.
【００１９】微細孔形成処理は、黒鉛化処理の前に、空
気や酸素ガスや水蒸気などの酸化性ガスの雰囲気下に、
例えば直径０．００５〜２．０μｍの流動気相成長炭素
繊維を予め５００℃〜１，１００℃、好ましくは６００
〜１，０００℃に加熱しても良いし、また、流動気相成
長炭素繊維の黒鉛化処理の後に、前記酸化性ガスの雰囲
気下に、黒鉛化処理後の繊維を６００℃〜１，１００℃
に加熱しても良い。The fine pore forming treatment is carried out in the atmosphere of an oxidizing gas such as air or oxygen gas or water vapor before the graphitization treatment.
For example, a fluidized vapor grown carbon fiber having a diameter of 0.005 to 2.0 μm is preliminarily 500 ° C. to 1,100 ° C., preferably 600.
It may be heated to ˜1,000 ° C., or after the graphitization of the fluidized vapor grown carbon fiber, the fiber after the graphitization is heated to 600 ° C. to 1,100 in an atmosphere of the oxidizing gas. ℃
You may heat to.
【００２０】この微細孔形成処理により、黒鉛繊維に微
細な穴が多数形成される。この微細孔は、黒鉛繊維の中
心部にまで達するものであり、単なるエッチング、薬品
による単なる表面処理では、到底形成され得ない。この
微細孔形成処理においては、前記微細孔を黒鉛繊維の表
面および表面から内部に向って均一に形成させることが
望ましい。By this fine hole forming treatment, many fine holes are formed in the graphite fiber. The fine pores reach the center of the graphite fiber and cannot be formed at all by simple etching or simple surface treatment with chemicals. In this fine pore forming treatment, it is desirable that the fine pores are uniformly formed on the surface of the graphite fiber and from the surface to the inside.
【００２１】そのためには、酸化処理における加熱時間
および加熱温度を注意深く選定することが肝要である。
たとえば、高温で長時間の酸化処理を行なうと、微細孔
の形成が過度になり、充放電を繰り返しても外形を十分
に維持可能な機械的強度を備えた黒鉛繊維を得ることが
できなくなることがある。そこで、微細孔形成処理にお
いて、加熱温度が高い場合には短時間に処理する必要が
あり、また、各繊維間における微細孔形成のばらつきを
小さくする必要も生じる。For that purpose, it is important to carefully select the heating time and the heating temperature in the oxidation treatment.
For example, if oxidation treatment is performed at high temperature for a long time, the formation of fine pores becomes excessive, and it becomes impossible to obtain graphite fibers with sufficient mechanical strength to maintain the outer shape even after repeated charging and discharging. There is. Therefore, in the fine pore forming treatment, when the heating temperature is high, it is necessary to perform the treatment in a short time, and it is also necessary to reduce the variation in fine pore formation among the fibers.
【００２２】黒鉛化処理前後における好ましい微細孔処
理として、たとえば、前記流動気相成長炭素繊維を容器
内に均一に軽く詰めた後、該容器を密封した状態で加熱
する方法が挙げられる。その理由は、容器内に予め存在
していた空気によってのみ微細孔が形成されるため、該
繊維の詰め方が均一であることにより、繊維間の微細孔
形成のばらつきがなくなるからである。また、微細孔の
形成の程度を変えるには、容器内部に空気を存在させて
おく代わりに酸素濃度を調節した混合ガスまたは酸素ガ
スを予め入れておくか、該繊維の容器内の充填率を変え
ることによって均一に適度の穿孔が行なえる。さらに、
必要に応じてこの操作を繰り返してもよい。電池用途に
おいては、酸化処理後に黒鉛化処理の工程がないとき
は、８００℃以上の加熱工程を設けて、酸素含有官能基
を分解しておくのが好ましい。A preferable method of fine pore treatment before and after the graphitization treatment is, for example, a method of uniformly and lightly packing the fluidized vapor grown carbon fiber in a container, and then heating the container in a sealed state. The reason is that the micropores are formed only by the air that is present in the container in advance, and the uniform packing of the fibers eliminates the variation in the micropore formation among the fibers. In order to change the degree of formation of fine pores, a mixed gas or oxygen gas with an adjusted oxygen concentration is added in advance instead of allowing air to exist inside the container, or the filling rate of the fiber in the container is changed. By changing it, it is possible to carry out uniform perforation. further,
You may repeat this operation as needed. In battery applications, when there is no graphitization process after the oxidation treatment, it is preferable to provide a heating process at 800 ° C. or higher to decompose the oxygen-containing functional group.
【００２３】[0023]
【発明の効果】本発明の黒鉛繊維は、年輪構造を有する
と共に特定の直径を有し、しかも表面から繊維軸に向か
う微細孔を有する多孔性であるから、例えば黒鉛繊維・
リチウム２次電池における電極活物質として使用するこ
とができ、また、微細孔によるアンカー効果のためか、
マトリックス材料と繊維との間の力の伝達がよくなって
補強効果が改善され、機械的強度の向上した複合材料を
与えることのできる補強材として使用することができ
る。EFFECT OF THE INVENTION The graphite fiber of the present invention has a ring structure, a specific diameter, and is porous having fine pores extending from the surface to the fiber axis.
It can be used as an electrode active material in a lithium secondary battery, and because of the anchor effect due to fine pores,
It can be used as a reinforcing material which can give a composite material with improved mechanical strength by improving the force transmission between the matrix material and the fibers and improving the reinforcing effect.
【００２４】本発明の黒鉛繊維は、流動気相成長炭素繊
維を黒鉛化処理するその前後において、微細孔処理をす
るだけで製造することができる。The graphite fiber of the present invention can be produced only by subjecting it to fine pore treatment before and after the graphitization treatment of the fluidized vapor growth carbon fiber.
【００２５】[0025]
（実施例１）直径０．２μｍ、長さ約１，０００μｍの
流動気相成長炭素繊維を２，９００℃で３０分かけて黒
鉛化処理して得られたところの、カサ比重が約０．０１
である黒鉛繊維１ｇを、内容積１００ｃｃの容器（ＳＵ
Ｓ３１０Ｓ）内に均一に充填した。次に、容器内の空気
を真空引きした後、該容器内に酸素ガスを導入して密閉
し、８００℃に加熱した電気炉内に１時間放置してから
冷却した。その後、容器の蓋を開け、内部のガスを抜い
てから、再び上記と同様にして該容器内に酸素ガスを導
入し、上記と同様の操作を繰り返した。その後、容器内
から取り出した上記黒鉛繊維を、不活性ガス中に２，０
００℃で３０分間加熱しても多孔性の黒鉛繊維を得た。(Example 1) A bulk specific gravity of about 0.2 was obtained by subjecting a fluidized vapor grown carbon fiber having a diameter of 0.2 µm and a length of about 1,000 µm to graphitization at 2,900 ° C for 30 minutes. 01
1 g of graphite fiber is a container with an internal volume of 100 cc (SU
S310S) was filled uniformly. Next, after the air in the container was evacuated, oxygen gas was introduced into the container to seal it, and the container was left in an electric furnace heated to 800 ° C. for 1 hour and then cooled. After that, the lid of the container was opened, the gas inside was released, and then oxygen gas was introduced into the container again in the same manner as above, and the same operation as above was repeated. After that, the graphite fiber taken out from the container was added to an inert gas for 2,0
Porous graphite fibers were obtained even when heated at 00 ° C. for 30 minutes.
【００２６】多孔性のこの黒鉛繊維の表面を走査型電子
顕微鏡で観察したところ、酸化による微細な穴ができて
いた。この黒鉛繊維正極活物質をバインダーと混合して
成形した後、約２００ｋｇ／ｃｍ2 の圧力で加圧して直
径１０ｍｍ、厚さ１〜２ｍｍ程度のペレット状混合電極
を作成した。When the surface of the porous graphite fiber was observed with a scanning electron microscope, fine holes were formed due to oxidation. This graphite fiber positive electrode active material was mixed with a binder and molded, and then pressed at a pressure of about 200 kg / cm 2 to prepare a pellet-shaped mixed electrode having a diameter of 10 mm and a thickness of about 1 to 2 mm.
【００２７】また、電極端子はペレット状混合電極の外
周をＰＡＮ系炭素繊維で巻き、これを直径２．３ｍｍの
ポリエチレンチューブで融着することにより絶縁被覆線
を形成してリード線を取り出した。リチウムを上記と同
様のペレット形状に成形したものを用い、ニッケル製リ
ード線を取り出した。As the electrode terminal, the outer periphery of the pellet-shaped mixed electrode was wrapped with PAN-based carbon fiber, and this was fused with a polyethylene tube having a diameter of 2.3 mm to form an insulating coated wire and the lead wire was taken out. A lead wire made of nickel was taken out by using lithium molded into a pellet shape similar to the above.
【００２８】また、リチウム導電性電解質としては、Ｌ
ｉＣｌＯ4 を使用した。これらを用いて、黒鉛繊維・リ
チウム２次電池を形成し、該電池の開回路電圧および放
電容量を測定したところ、開回路電圧は約４．５Ｖであ
り、放電容量は４８ｍＡｈ／ｇであった。また、４．５
Ｖ−３．０Ｖの充放電を１００回繰り返した後の放電容
量の減少は２０％であった。The lithium conductive electrolyte is L
iClO 4 was used. Using these, a graphite fiber / lithium secondary battery was formed, and the open circuit voltage and discharge capacity of the battery were measured. The open circuit voltage was about 4.5 V and the discharge capacity was 48 mAh / g. . Also 4.5
The decrease in discharge capacity after repeating charging and discharging at V-3.0V 100 times was 20%.
【００２９】（実施例２）前記実施例１で用いたカサ比
重０．０１の流動気相成長炭素繊維を内容積１００ｃｃ
の容器（ＳＵＳ３１０Ｓ）内に均一に充填した後、該容
器内の空気を真空引きした。その後、該容器内に酸素ガ
スを導入して密閉し、６００℃で１時間加熱してから冷
却した。次に上記繊維をアルゴンガス中に２，９００℃
で黒鉛化処理した。以下、前記実施例１と同様に実施し
て黒鉛繊維・リチウム２次電池を形成した。該電池の開
回路電圧および放電容量を測定したところ、開回路電圧
は約４．５Ｖであり、放電容量は４５ｍＡｈ／ｇであっ
た。また、４．５Ｖ−３．０Ｖの充放電を１００回繰り
返した後の放電容量の減少は２１％であった。(Example 2) The fluidized vapor grown carbon fiber having a bulk specific gravity of 0.01 used in Example 1 had an internal volume of 100 cc.
After uniformly filling the container (SUS310S), the air in the container was evacuated. After that, oxygen gas was introduced into the container and the container was sealed, heated at 600 ° C. for 1 hour, and then cooled. Next, the above fibers were placed in argon gas at 2,900 ° C.
Was graphitized. Thereafter, the same procedure as in Example 1 was performed to form a graphite fiber / lithium secondary battery. When the open circuit voltage and the discharge capacity of the battery were measured, the open circuit voltage was about 4.5 V and the discharge capacity was 45 mAh / g. In addition, the decrease in discharge capacity after repeating charging / discharging at 4.5V-3.0V 100 times was 21%.
【００３０】（実施例３）直径０．５μｍ、長さ８０μ
ｍの流動気相成長炭素繊維を２，８００℃で３０分かけ
て黒鉛化処理して得られたところの、嵩比重が約０．１
３である黒鉛繊維３０ｇを内容積２３０ｃｃの容器（Ｓ
ＵＳ３１０Ｓ）内に均一に充填した。次に、容器内の空
気を真空引きしたのち、該容器内に酸素ガスを導入して
密閉し、１，０００℃に加熱された電気炉内に１時間放
置してから、冷却した。その後、容器の蓋を開け、内部
のガスを抜いてから再び上記と同様にして該容器内に酸
素ガスを導入し、上記と同様の操作を３回繰り返した。
これにより、多孔性黒鉛繊維が得られた。Example 3 Diameter 0.5 μm, Length 80 μ
The bulk specific gravity was about 0.1, which was obtained by graphitizing the fluidized vapor grown carbon fiber of m at 2,800 ° C. for 30 minutes.
30 g of graphite fiber, which is No. 3, is a container with an internal volume of 230 cc (S
It was uniformly filled in US310S). Next, after the air in the container was evacuated, oxygen gas was introduced into the container to seal the container, and the container was allowed to stand in an electric furnace heated to 1,000 ° C. for 1 hour and then cooled. After that, the lid of the container was opened, the gas inside was removed, and then oxygen gas was introduced into the container again in the same manner as above, and the same operation as above was repeated three times.
As a result, porous graphite fiber was obtained.
【００３１】次に、エポキシ樹脂（チバガイギー社製、
ＬＹ−５５６）１００重量部と硬化剤（チバガイギー社
製、ＨＹ−９１７Ｊ）９０重量部とからなる樹脂組成物
をマトリックスとして、この樹脂組成物中に体積割合が
２０％になるように前記多孔性黒鉛繊維を配合し、１２
０℃に２時間保持して硬化させ、複合材料を得た。この
複合材料につき、ＪＩＳ Ｋ７２０３に準じて曲げ試験
を行なった。その結果、曲げ強度は２２．１Ｋｇ／ｍｍ
2 、曲げ弾性率は６６５Ｋｇ／ｍｍ2 であった。Next, an epoxy resin (manufactured by Ciba Geigy,
The resin composition consisting of 100 parts by weight of LY-556) and 90 parts by weight of a curing agent (HY-917J manufactured by Ciba-Geigy) is used as a matrix, and the porosity is adjusted so that the volume ratio of the resin composition is 20%. Blended with graphite fiber, 12
The composite material was obtained by holding it at 0 ° C. for 2 hours for curing. This composite material was subjected to a bending test according to JIS K7203. As a result, the bending strength is 22.1 Kg / mm.
2 , the flexural modulus was 665 Kg / mm 2 .
【００３２】（比較例１）直径７μｍのＰＡＮ系炭素繊
維を３ｍｍの長さにカットして電極活物質とした以外は
前記実施例１と同様に実施して黒鉛繊維・リチウム２次
電池を形成した。該電池の開回路電圧および放電容量を
測定したところ、開回路電圧は約４．５Ｖであり、放電
容量は１９ｍＡｈ／ｇであった。また、４．５Ｖ−３．
０Ｖの充放電を１００回繰り返した後の放電容量の減少
は７０％であった。 （比較例２）直径１０ｍｍの基板法気相成長炭素繊維を
電極活物質とした以外は前記実施例２と同様に実施して
黒鉛繊維・リチウム２次電池を形成した。該電池の開回
路電圧および放電容量を測定したところ、開回路電圧は
約４．５Ｖであり、放電容量は２２ｍＡｈ／ｇであっ
た。また、４．５Ｖ−３．０Ｖの充放電を１００回繰り
返した後の放電容量の減少は７３％であった。Comparative Example 1 A graphite fiber / lithium secondary battery was formed in the same manner as in Example 1 except that PAN-based carbon fiber having a diameter of 7 μm was cut into a length of 3 mm to obtain an electrode active material. did. When the open circuit voltage and the discharge capacity of the battery were measured, the open circuit voltage was about 4.5 V and the discharge capacity was 19 mAh / g. Also, 4.5V-3.
The decrease in discharge capacity after repeating 0 V charge and discharge 100 times was 70%. (Comparative Example 2) A graphite fiber / lithium secondary battery was formed in the same manner as in Example 2 except that the substrate-active vapor grown carbon fiber having a diameter of 10 mm was used as the electrode active material. When the open circuit voltage and the discharge capacity of the battery were measured, the open circuit voltage was about 4.5 V and the discharge capacity was 22 mAh / g. In addition, the decrease in discharge capacity after repeating charging / discharging at 4.5V-3.0V 100 times was 73%.
【００３３】（比較例３）実施例３で用いた黒鉛繊維を
酸化処理することなしに実施例３の樹脂組成物中に同様
の比率で配合し、同様の条件で硬化させることにより複
合材料を得た。この複合材料につき、実施例３と同様に
して曲げ試験を行なった。その結果、曲げ強度は１４．
１Ｋｇ／ｍｍ2 、曲げ弾性率は５１６Ｋｇ／ｍｍ2 であ
った。(Comparative Example 3) The composite material was prepared by mixing the graphite fiber used in Example 3 in the resin composition of Example 3 in the same ratio without oxidation treatment and curing it under the same conditions. Obtained. A bending test was performed on this composite material in the same manner as in Example 3. As a result, the bending strength is 14.
1 kg / mm 2, a flexural modulus of 516Kg / mm 2.
Claims (3)
年輪構造を有するとともに、直径が０．００５〜２．０
μｍであり、かつ多孔性であることを特徴とする黒鉛繊
維。1. A carbon ring having a hexagonal mesh plane concentrically stacked in an annual ring structure and having a diameter of 0.005 to 2.0.
Graphite fiber characterized by having a size of μm and being porous.
上の温度で黒鉛化処理し、次いで５００〜１，１００℃
の温度で酸化処理することを特徴とする黒鉛繊維の製造
方法。2. A fluidized vapor grown carbon fiber is graphitized at a temperature of 2,000 ° C. or higher, and then 500 to 1,100 ° C.
A method for producing a graphite fiber, characterized in that the graphite fiber is subjected to an oxidation treatment at the temperature of.
００℃の温度で予め酸化処理をし、次いで２，０００℃
以上の温度で不活性気流中にて黒鉛化処理することを特
徴とする黒鉛繊維の製造方法。3. A fluidized vapor grown carbon fiber comprising 500 to 1,1.
Pre-oxidized at a temperature of 00 ° C, then 2,000 ° C
A method for producing a graphite fiber, which comprises performing graphitization in an inert gas stream at the above temperature.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3164787A JP2664819B2 (en) | 1991-07-05 | 1991-07-05 | Graphite fiber and method for producing the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3164787A JP2664819B2 (en) | 1991-07-05 | 1991-07-05 | Graphite fiber and method for producing the same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH06212517A true JPH06212517A (en) | 1994-08-02 |
| JP2664819B2 JP2664819B2 (en) | 1997-10-22 |
Family
ID=15799941
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3164787A Expired - Lifetime JP2664819B2 (en) | 1991-07-05 | 1991-07-05 | Graphite fiber and method for producing the same |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2664819B2 (en) |
Cited By (5)
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|---|---|---|---|---|
| JPH0997603A (en) * | 1995-09-29 | 1997-04-08 | Toray Ind Inc | Manufacture of electrode sheet for battery |
| JP2002110233A (en) * | 2000-09-29 | 2002-04-12 | Toshiba Corp | Non-aqueous electrolyte secondary battery |
| US6946110B2 (en) * | 1999-03-25 | 2005-09-20 | Showa Denko K.K. | Carbon fibers, production process therefor and electrode for batteries |
| US7214408B2 (en) | 2003-08-28 | 2007-05-08 | Canon Kabushiki Kaisha | Method of producing carbon fiber aggregate |
| WO2010128650A3 (en) * | 2009-05-06 | 2011-01-06 | 株式会社インキュベーション・アライアンス | Carbon material and manufacturing method therefor |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8951451B2 (en) | 2009-05-26 | 2015-02-10 | Incubation Alliance, Inc. | Carbon material and method for producing same |
| WO2011102473A1 (en) * | 2010-02-19 | 2011-08-25 | 株式会社インキュベーション・アライアンス | Carbon material and method for producing same |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0997603A (en) * | 1995-09-29 | 1997-04-08 | Toray Ind Inc | Manufacture of electrode sheet for battery |
| US6946110B2 (en) * | 1999-03-25 | 2005-09-20 | Showa Denko K.K. | Carbon fibers, production process therefor and electrode for batteries |
| JP2002110233A (en) * | 2000-09-29 | 2002-04-12 | Toshiba Corp | Non-aqueous electrolyte secondary battery |
| US7214408B2 (en) | 2003-08-28 | 2007-05-08 | Canon Kabushiki Kaisha | Method of producing carbon fiber aggregate |
| WO2010128650A3 (en) * | 2009-05-06 | 2011-01-06 | 株式会社インキュベーション・アライアンス | Carbon material and manufacturing method therefor |
| KR101446638B1 (en) * | 2009-05-06 | 2014-10-02 | 가부시키가이샤 인큐베이션 얼라이언스 | Carbon material and manufacturing method therefor |
| JP5613662B2 (en) * | 2009-05-06 | 2014-10-29 | 株式会社インキュベーション・アライアンス | Carbon material and manufacturing method thereof |
| US8883112B2 (en) | 2009-05-06 | 2014-11-11 | Incubation Alliance, Inc. | Carbon material and method for producing same |
| US9379385B2 (en) | 2009-05-06 | 2016-06-28 | Incubation Alliance, Inc. | Carbon material and method for producing same |
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| JP2664819B2 (en) | 1997-10-22 |
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