JP2844302B2 - Carbon negative electrode material for lithium secondary battery and method for producing the same - Google Patents

Carbon negative electrode material for lithium secondary battery and method for producing the same

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Publication number
JP2844302B2
JP2844302B2 JP6021344A JP2134494A JP2844302B2 JP 2844302 B2 JP2844302 B2 JP 2844302B2 JP 6021344 A JP6021344 A JP 6021344A JP 2134494 A JP2134494 A JP 2134494A JP 2844302 B2 JP2844302 B2 JP 2844302B2
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JP
Japan
Prior art keywords
carbon
secondary battery
negative electrode
lithium secondary
electrolyte
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Expired - Fee Related
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JP6021344A
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Japanese (ja)
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JPH07230803A (en
Inventor
琢志 大崎
隆一 矢崎
博司 平
章 若泉
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Nippon Sanso Corp
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Nippon Sanso Corp
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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
    • 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

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  • Carbon And Carbon Compounds (AREA)
  • Inert Electrodes (AREA)
  • Secondary Cells (AREA)
  • Battery Electrode And Active Subsutance (AREA)

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【０００１】[0001]

【産業上の利用分野】本発明は、充放電可能なリチウム
二次電池の負極に適したリチウム二次電池用の炭素負極
材及びその製造方法に関する。The present invention relates to a method for producing a carbon Fukyokuzai及patron for a lithium secondary battery suitable for the negative electrode of the rechargeable lithium secondary battery.

【０００２】[0002]

【従来の技術】有機溶媒を電解液として、負極に金属リ
チウムを用いたリチウム一次電池は、多くの利点がある
ことから広く普及している。この電池の負極では使用時
（放電時）に、金属リチウムがリチウムイオンに酸化さ
れて溶出し、同時に生成した自由電子が外部回路に供給
される。2. Description of the Related Art Lithium primary batteries using an organic solvent as an electrolyte and lithium metal as a negative electrode are widely used because of their many advantages. In the negative electrode of this battery, during use (during discharge), metallic lithium is oxidized and eluted into lithium ions, and simultaneously generated free electrons are supplied to an external circuit.

【０００３】このリチウム一次電池の優れた性能を活か
して充放電可能な二次電池としてそのままの構成で使用
しようとすると、充電時には、上記金属リチウム極で放
電時と逆に、外部回路から供給された自由電子によりリ
チウムイオンが還元されて金属リチウムが析出すること
になる。[0003] If an attempt is made to use this lithium primary battery as it is as a chargeable / dischargeable secondary battery by taking advantage of its excellent performance, it is supplied from an external circuit at the time of charging, contrary to the time of discharging at the above-mentioned metal lithium electrode. Lithium ions are reduced by the free electrons, and metallic lithium is deposited.

【０００４】[0004]

【発明が解決しようとする課題】しかしながら、上記負
極で金属リチウムが析出する際、金属リチウムが粒子状
乃至樹枝状に析出してしまい、負極が元の状態に戻ら
ず、正負極の短絡等、様々な障害を引起こすため、可逆
的に充放電を繰返す二次電池として使用することはでき
なかった。However, when metallic lithium is deposited on the negative electrode, the metallic lithium precipitates in the form of particles or dendrites, so that the negative electrode does not return to its original state and the positive electrode and the negative electrode are short-circuited. Since it causes various obstacles, it cannot be used as a secondary battery that repeatedly charges and discharges reversibly.

【０００５】最近の研究では、金属リチウムに代えて負
極に炭素材料を用いると、該炭素材料がリチウムイオン
を可逆的に取込み（ドープ）、放出（脱ドープ）して、
充放電可能な二次電池として使用できることが提唱さ
れ、実用化されつつある。すなわち、負極の炭素材にリ
チウムイオンをドープすることにより充電し、放電時に
は逆にリチウムイオンを脱ドープすることになる。した
がって、炭素材料のリチウムイオンのドープ量によって
負極での充電容量が、そして、脱ドープ量によって負極
での放電容量が決まる。In a recent study, when a carbon material was used for the negative electrode instead of metallic lithium, the carbon material reversibly took in (doped) and released (undoped) lithium ions,
It has been proposed that it can be used as a chargeable / dischargeable secondary battery, and is being put to practical use. That is, the carbon material of the negative electrode is charged by doping lithium ions, and the lithium ions are undoped during discharging. Therefore, the charge capacity at the negative electrode is determined by the doping amount of lithium ions in the carbon material, and the discharge capacity at the negative electrode is determined by the undoped amount.

【０００６】上記リチウム二次電池の負極に用いる炭素
材料としては、当初は、リチウムイオンを層間化合物と
して取込むことができる黒鉛が注目された。この場合、
炭素原子６個にリチウム原子１個の割合が、理論的に
は、負極での最大ドープ量（取込み量）であり、それに
よって最大充電容量も決まる。As a carbon material used for the negative electrode of the lithium secondary battery, graphite, which can take in lithium ions as an interlayer compound, has been noticed at first. in this case,
The ratio of one lithium atom to six carbon atoms is theoretically the maximum doping amount (incorporation amount) in the negative electrode, and the maximum charging capacity is also determined thereby.

【０００７】したがって、リチウム二次電池の電池容量
を向上させるためには、負極に用いる炭素材料の充電容
量を向上させるだけでなく、その時の放電容量を充電容
量に近付けて不可逆容量を極小化することが必要であ
る。Accordingly, in order to improve the battery capacity of the lithium secondary battery, not only the charge capacity of the carbon material used for the negative electrode is improved, but also the discharge capacity at that time is made closer to the charge capacity to minimize the irreversible capacity. It is necessary.

【０００８】このようなことから、近年、比表面積の大
きい多孔質材料である難黒鉛化性炭素材料を用いると、
前記黒鉛を用いたときの理論量を上回る電池容量が得ら
れることが報告された。この難黒鉛化性炭素材料は、一
般に、炭素を主成分とする有機化合物を乾留し、熱処理
によって炭素原子の配列構造を発達させることにより製
造されている。そして、後工程の熱処理によって、難黒
鉛化性炭素材料の最終的な特性が制御されるので、電池
容量（放電容量及び充電容量）は、その熱処理温度に大
きく依存する。For these reasons, in recent years, when a non-graphitizable carbon material which is a porous material having a large specific surface area is used,
It was reported that a battery capacity exceeding the theoretical amount when using the graphite was obtained. This non-graphitizable carbon material is generally produced by carbonizing an organic compound containing carbon as a main component, and developing an array structure of carbon atoms by heat treatment. Then, the final characteristics of the non-graphitizable carbon material are controlled by the heat treatment in the post-process, so that the battery capacity (discharge capacity and charge capacity) greatly depends on the heat treatment temperature.

【０００９】また、リチウム二次電池の負極に、フルフ
リルアルコール樹脂を原料とした難黒鉛化性炭素材料を
用いた場合の熱処理温度と電池容量との関係において、
充電容量は、熱処理温度が比較的低温の８００℃で最大
値となるが、放電容量は、熱処理温度が比較的高温の１
１００℃で最大値となることが報告されている。したが
って、８００℃で熱処理しても、充電量が全部放電に消
費されず、不可逆容量が残ることになる。実用上は、放
電容量最大の熱処理温度１１００℃を採用することにな
るので、不十分な充電量の状態で使用することになる。
すなわち、従来の炭素材料を負極として用いたリチウム
二次電池では、充電容量を高めると放電効率（放電量を
充電量で除した値）が減少し、放電量が少なくなるとい
う不都合があった。Further, in the case where a non-graphitizable carbon material using a furfuryl alcohol resin as a raw material is used for a negative electrode of a lithium secondary battery, the relationship between the heat treatment temperature and the battery capacity is as follows.
The charge capacity reaches its maximum value at 800 ° C. where the heat treatment temperature is relatively low.
It is reported that the maximum value is obtained at 100 ° C. Therefore, even if the heat treatment is performed at 800 ° C., the entire charge amount is not consumed for discharging, and the irreversible capacity remains. In practice, the heat treatment temperature of 1100 ° C., which has the maximum discharge capacity, is adopted, so that the battery is used in an insufficiently charged state.
That is, in a conventional lithium secondary battery using a carbon material as a negative electrode, increasing the charge capacity decreases discharge efficiency (a value obtained by dividing the discharge amount by the charge amount), and reduces the discharge amount.

【００１０】しかしながら、リチウム二次電池におい
て、上記の難黒鉛化性炭素電極にリチウムイオンがどの
ようにドープされ、脱ドープされるのかという電極反応
のメカニズムについてはいまだ定説がなく、したがっ
て、前述したように充電容量と放電容量とが一致しない
不可逆容量の原因についても明確にされていないのが実
状である。However, in a lithium secondary battery, the mechanism of the electrode reaction on how the above-mentioned non-graphitizable carbon electrode is doped and de-doped with lithium ions has not been established yet. As described above, the cause of the irreversible capacity in which the charge capacity and the discharge capacity do not match has not been clarified.

【００１１】そこで本発明者らは、リチウム二次電池の
負極として用いる難黒鉛化性炭素の挙動を考究し、充電
容量の向上とともに充電量を最大限に放電させて不可逆
容量を極小化させ、電池容量に優れたリチウム二次電池
を得ることを目的として鋭意研究を重ねた。その結果、
負極となる難黒鉛化性炭素への有機溶媒の吸着量を少な
くすると、充電容量を高めても放電効率がそれほど減少
しないことを知見した。すなわち、難黒鉛化性炭素の物
理化学的特性と、それを用いた時の充放電容量との関係
を考究した結果、リチウム二次電池の電解液として用い
る有機溶媒の難黒鉛化性炭素への吸着量が、電池容量、
特に、放電容量に著しい影響を与えることを見出した。
つまり、難黒鉛化性炭素への有機溶媒の吸着量が大きい
と、放電容量が低下するという知見を得た。Therefore, the present inventors have studied the behavior of non-graphitizable carbon used as a negative electrode of a lithium secondary battery, and minimized the irreversible capacity by discharging the charge amount as much as possible while improving the charge capacity. Intensive research was conducted with the aim of obtaining a lithium secondary battery with excellent battery capacity. as a result,
It has been found that when the amount of the organic solvent adsorbed on the non-graphitizable carbon serving as the negative electrode is reduced, the discharge efficiency does not decrease so much even when the charge capacity is increased. That is, as a result of studying the relationship between the physicochemical properties of non-graphitizable carbon and the charge / discharge capacity when using it, the organic solvent used as the electrolyte of the lithium secondary battery was converted to non-graphitizable carbon The amount of adsorption depends on battery capacity,
In particular, it has been found that the discharge capacity is significantly affected.
That is, it was found that when the amount of the organic solvent adsorbed on the non-graphitizable carbon was large, the discharge capacity was reduced.

【００１２】[0012]

【課題を解決するための手段】本発明のリチウム二次電
池用の炭素負極材は、上記知見に基づいて成されたもの
で、炭素負極材を構成する難黒鉛化性炭素の微粒子表面
の細孔入口径を、リチウム二次電池の電解液中のリチウ
ムイオンが通過可能で、かつ、電解液中の有機溶媒が実
質的に通過不可能な径としたことを特徴とする。また、
前記難黒鉛化性炭素の微粒子は、その内部に電解液中の
有機溶媒を吸着できる細孔があり、該難黒鉛化性炭素の
表面には熱分解炭素が析出しており、その結果前記細孔
は、電解液中のリチウムイオンがドープ及び脱ドープ可
能であるとともに電解液中の有機溶媒がみかけ上吸着不
可能であること、平均粒径を半分以下に粉砕したときの
電解液中の有機溶媒の吸着量が２．５〜２４．９重量％
であること、結合剤とペースト化剤とを添加してプレス
成型されていることを特徴としている。さらに、前記難
黒鉛化性炭素の微粒子の表面に析出した熱分解炭素は、
熱分解性炭化水素の熱分解法により析出されたものであ
り、前記熱分解性炭化水素は、トルエン、ベンゼン、ブ
タン、２，４−キシレノール、キノリン、クレオソート
のいずれかであることを特徴としている。また、前記電
解液中の有機溶媒は、プロピレンカーボネートとジメト
キシエタンの１：１混合液であり、前記電解液中の支持
電解質は、過塩素酸リチウムであることを特徴としてい
る。 The carbon anode material for a lithium secondary battery of the present invention has been made based on the above findings, and has a fine surface of fine graphitizable carbon fine particles constituting the carbon anode material. The hole inlet diameter is characterized in that the diameter is such that lithium ions in the electrolyte of the lithium secondary battery can pass through and the organic solvent in the electrolyte does not substantially pass. Also,
The particles of the non-graphitizable carbon are contained inside the electrolyte solution.
There are pores that can adsorb organic solvents, and the hardly graphitizable carbon
Pyrolytic carbon is deposited on the surface, resulting in the pores
Indicates that lithium ions in the electrolyte can be doped and undoped.
And the organic solvent in the electrolyte is apparently not adsorbed.
Possible, when the average particle size is crushed to less than half
The adsorption amount of the organic solvent in the electrolyte is 2.5 to 24.9% by weight.
, Adding a binder and a paste agent and pressing
It is characterized by being molded. Further, the difficulty
Pyrolytic carbon deposited on the surface of the graphitizable carbon fine particles,
Deposited by pyrolysis of pyrolytic hydrocarbons
The thermally decomposable hydrocarbons include toluene, benzene,
Tan, 2,4-xylenol, quinoline, creosote
Which is one of the following. In addition, the electric
The organic solvents in the solution were propylene carbonate and
A 1: 1 mixture of xyethane, supported in the electrolyte
The electrolyte is characterized by being lithium perchlorate.
You.

【００１３】本発明のリチウム二次電池用の炭素負極材
の製造方法は、炭素負極材を構成する難黒鉛化性炭素の
微粒子表面の細孔入口径を、リチウム二次電池の電解液
中のリチウムイオンが通過可能で、かつ、電解液中の有
機溶媒が実質的に通過不可能な径に形成することを特徴
とする。また、前記難黒鉛化性炭素の微粒子に、加熱下
で熱分解性炭化水素を接触せしめて微粒子表面に熱分解
炭素を析出させ、電解液中の有機溶媒を吸着できる微粒
子の細孔を、電解液中のリチウムイオンがドープ及び脱
ドープ可能であるとともに電解液中の有機溶媒がみかけ
上吸着不可能に形成することを特徴とする。さらに、前
記難黒鉛化性炭素の微粒子は、フェノール樹脂又はフラ
ン樹脂を乾留した後熱処理し、次いで粉砕したものであ
ることを特徴とし、前記フェノール樹脂の熱処理温度
は、８００〜９００℃であることを特徴としている。ま
た、前記難黒鉛化性炭素の微粒子は、ヤシガラチャーを
脱アルカリした後熱処理し、次いで粉砕したものである
ことを特徴とし、前記ヤシガラチャーの脱アルカリは、
希塩酸で洗浄することを特徴としている。さらに、前記
難黒鉛化性炭素の微粒子は、結合剤とペースト化剤とを
添加してプレス成型することを特徴とする。また、前記
熱分解性炭化水素は、トルエン、ベンゼン、ブタン、
２，４−キシレノール、キノリン、クレオソートのいず
れかであることを特徴とする。さらに、前記電解液中の
有機溶媒は、プロピレンカーボネートとジメトキシエタ
ンの１：１混合液であり、前記電解液中の支持電解質
は、過塩素酸リチウムであることを特徴としている。 The carbon anode material for a lithium secondary battery of the present invention
Is a method of producing the non-graphitizable carbon constituting the carbon anode material.
The pore inlet diameter on the surface of the fine particles is adjusted to the electrolyte of the lithium secondary battery.
Lithium ions can pass through and the electrolyte
Characterized in that the solvent solvent is formed to a diameter that is substantially impermeable.
And Further, the particles of the non-graphitizable carbon are heated under heat.
Decomposes the surface of fine particles by contacting pyrolytic hydrocarbons
Fine particles capable of depositing carbon and adsorbing organic solvent in electrolyte
Lithium ions in the electrolyte dope and desorb the pores of the
Organic solvent in electrolyte can be seen while doping is possible
It is characterized in that it is formed so as not to be adsorbed. Furthermore, before
Fine particles of the non-graphitizable carbon are made of phenol resin or flour.
Heat-treated after carbonizing the resin, and then pulverized.
Characterized in that the heat treatment temperature of the phenolic resin
Is 800 to 900 ° C. Ma
The fine particles of non-graphitizable carbon may have a coconut crush.
It is heat-treated, then pulverized after dealkalization.
It is characterized in that the dealkalization of the coconut pulp,
It is characterized by washing with dilute hydrochloric acid. In addition,
Fine particles of non-graphitizable carbon consist of a binder and a paste agent.
It is characterized by adding and press-molding. In addition,
Pyrolytic hydrocarbons include toluene, benzene, butane,
2,4-xylenol, quinoline, creosote
It is characterized by this. Further, in the electrolyte solution
Organic solvents are propylene carbonate and dimethoxyethanol.
And a supporting electrolyte in the electrolyte.
Is characterized by being lithium perchlorate.

【００１４】一般に、上記難黒鉛化性炭素は細孔の多い
多孔質材料であって、極めて大きな比表面積を有する。
このような表面活性が、リチウムイオンを多く取込み、
電極触媒能を高める主要な原因と考えられる。そして、
このことが、同時に、電解液として用いられている有機
溶媒の吸着量も増加させることになる。ところが、前述
したように、有機溶媒の吸着量が多いと放電容量を減少
させるので、これを防止するためには比表面積の大きい
多孔質特性を保ちつつ、有機溶媒の吸着量を極力低下さ
せる必要がある。Generally, the non-graphitizable carbon is a porous material having many pores and has an extremely large specific surface area.
Such surface activity takes up a lot of lithium ions,
It is considered to be the main cause of enhancing the electrocatalytic ability. And
This also increases the amount of adsorption of the organic solvent used as the electrolyte. However, as described above, when the amount of organic solvent adsorbed is large, the discharge capacity is reduced. To prevent this, it is necessary to reduce the amount of adsorbed organic solvent as much as possible while maintaining the porous property with a large specific surface area. There is.

【００１５】一方、難黒鉛化性炭素の細孔入口径は、分
子篩炭素の製造工程で行われているように、熱分解性炭
化水素の熱分解法により細孔の入口に炭素を析出させる
ことで調整することが可能である。したがって、熱分解
性炭化水素の熱分解法における処理条件を最適な条件に
選定することにより、リチウムイオンは自由に出入りで
きるが、有機溶媒は細孔内に侵入することができない径
にすることができ、この場合、難黒鉛化性炭素の細孔容
積は実質的に変わらない。On the other hand, the diameter of the pore inlet of the non-graphitizable carbon is determined by depositing carbon at the inlet of the pore by a pyrolysis method of a pyrolytic hydrocarbon as in the production process of molecular sieve carbon. Can be adjusted. Therefore, by selecting the optimum treatment conditions in the pyrolysis method for pyrolytic hydrocarbons, it is possible to make the diameter such that lithium ions can freely enter and exit, but the organic solvent cannot enter the pores. In this case, the pore volume of the non-graphitizable carbon does not substantially change.

【００１６】すなわち、細孔の入口部分に、熱分解で生
じた炭素を析出させて細孔の入口径を絞ることにより、
リチウムイオンがドープされる細孔容積を変えずに、有
機溶媒の吸着量を実質的に零、すなわち、電解液中の有
機溶媒がみかけ上吸着不可能にすることができる。That is, by depositing carbon generated by thermal decomposition at the entrance of the pores and narrowing the entrance diameter of the pores,
The adsorption amount of the organic solvent is substantially zero without changing the pore volume in which lithium ions are doped , that is, the amount of
Solvent can be made apparently impossible to adsorb .

【００１７】[0017]

【作 用】上述の炭素負極材によれば、難黒鉛化性炭素
微粒子の細孔入口径が、リチウムイオンが通過可能で、
該リチウムイオンに比べて大きな分子サイズを有する有
機溶媒が通過不可能な径となっているので、難黒鉛化性
炭素微粒子の細孔には、リチウムイオンは侵入できるが
有機溶媒は実質的に侵入できず、放電容量低下の原因と
なる有機溶媒がみかけ上吸着不可能になる。このよう
に、難黒鉛化性炭素の細孔にリチウムイオンのみを侵入
可能としたので、放電効率は余り低下せず、充電量を高
めるほど放電量も増加することができる。これによっ
て、放電容量を充電容量に近付けることができ、リチウ
ム二次電池の電池容量を飛躍的に向上させることができ
る。 [Action] According to the above-described carbon anode material, the pore entrance diameter of the non-graphitizable carbon fine particles is such that lithium ions can pass therethrough.
Since the diameter of the organic solvent having a molecular size larger than that of the lithium ions is not allowed to pass through, the lithium ions can penetrate into the pores of the non-graphitizable carbon fine particles, but the organic solvent substantially penetrates. In this case, an organic solvent that causes a decrease in discharge capacity cannot be adsorbed apparently . As described above, since only lithium ions can enter the pores of the non-graphitizable carbon, the discharge efficiency does not decrease so much, and the discharge amount can be increased as the charge amount is increased. By this
Te, it is possible to close the discharge capacity to the charge capacity, lithium
Battery capacity of secondary batteries can be dramatically improved.
You.

【００１８】上述の炭素負極材の製造方法は、乾留した
フェノール樹脂若しくはフラン樹脂又は脱アルカリした
ヤシガラチャーを熱処理し、次いで粉砕した後、加熱下
でトルエン、ベンゼン、ブタン、２，４−キシレノー
ル、キノリン、クレオソートのいずれかの熱分解性炭化
水素を接触せしめて微粒子表面に熱分解炭素を析出させ
ることにより、炭素負極材を構成する難黒鉛化性炭素の
微粒子表面の細孔入口径を、リチウム二次電池の電解液
中のリチウムイオンが通過可能で、かつ、電解液中の有
機溶媒が実質的に通過不可能な径に形成でき、電解液中
の有機溶媒を吸着できる微粒子の細孔は、電解液中のリ
チウムイオンがドープ及び脱ドープ可能であるとともに
電解液中の有機溶媒がみかけ上吸着不可能に形成でき
る。 In the above-described method for producing a carbon anode material,
Phenol resin or furan resin or dealkalized
After heat-treating and then grinding the coconut garnish,
With toluene, benzene, butane, 2,4-xylenol
, Quinoline or creosote pyrolytic carbonization
Contact with hydrogen to deposit pyrolytic carbon on the surface of fine particles
By doing so, the non-graphitizable carbon
The pore inlet diameter on the surface of the fine particles is adjusted to the electrolyte of the lithium secondary battery.
Lithium ions can pass through and the electrolyte
Solvent solvent can be formed to a diameter that is substantially impermeable,
The fine pores of the fine particles that can adsorb the organic solvent
As well as being capable of doping and undoping
The organic solvent in the electrolyte can be formed so that it cannot be adsorbed
You.

【００１９】[0019]

【実施例】以下、本発明の実施例を説明する。本発明の
リチウム二次電池に使用される負極は、特定の処理を施
した難黒鉛化性炭素からなる負極材を所望の形状に加工
したものである。まず上記負極材を製造し、細孔入口径
の確認試験を行った。これを実施例１に示す。Embodiments of the present invention will be described below. The negative electrode used in the lithium secondary battery of the present invention is obtained by processing a negative electrode material made of non-graphitizable carbon having been subjected to a specific treatment into a desired shape. First, the negative electrode material was manufactured, and a confirmation test of a pore entrance diameter was performed. This is shown in Example 1.

【００２０】実施例１ 負極材となる難黒鉛化性炭素の原料としてフェノール樹
脂（群栄化学工業（株）製 ＰＧＡ−４５６０）を用
い、これを５５０℃で乾留した後、窒素気流中８００℃
で１時間熱処理して難黒鉛化性炭素を得た。次いで、こ
の難黒鉛化性炭素をアルミナボールを用いた振動ボール
ミルにて１０分間粉砕した。得られた難黒鉛化性炭素粒
子の平均粒径をレーザー散乱光回折式粒度分布測定器で
測定した結果、６．２μｍであった。Example 1 A phenol resin (PGA-4560 manufactured by Gunei Chemical Industry Co., Ltd.) was used as a raw material of non-graphitizable carbon as a negative electrode material, which was carbonized at 550 ° C., and then 800 ° C. in a nitrogen stream.
For 1 hour to obtain non-graphitizable carbon. Next, the non-graphitizable carbon was pulverized for 10 minutes by a vibration ball mill using alumina balls. As a result of measuring the average particle size of the obtained non-graphitizable carbon particles with a laser scattering light diffraction type particle size distribution analyzer, it was 6.2 μm.

【００２１】次に、細孔入口径を調整するための処理と
して、上記難黒鉛化性炭素微粒子を７００℃に加熱する
とともに、２５℃でトルエンを飽和した窒素ガスを毎分
３リットルの割合で１時間流し、その表面に、トルエン
の熱分解により生じた炭素を析出させた。Next, as a treatment for adjusting the pore entrance diameter, the non-graphitizable carbon fine particles were heated to 700 ° C., and nitrogen gas saturated with toluene at 25 ° C. was supplied at a rate of 3 liters per minute. After flowing for 1 hour, carbon generated by thermal decomposition of toluene was deposited on the surface.

【００２２】さらに、上記処理後の難黒鉛化性炭素粒子
を再粉砕し、再粉砕の前後における各細孔容積と、電池
の溶媒であるプロピレンカーボネート（ＰＣ）及びジメ
トキシエタン（ＤＭＥ）の吸着量とをそれぞれ測定し、
上記細孔入口径の調整処理を行うことにより細孔入口径
が絞られたことを確認した。その結果を表１に示す。な
お、再粉砕時間は、２時間及び２０時間とした。Further, the non-graphitizable carbon particles after the above treatment are crushed again, and the pore volumes before and after the crushing and the adsorption amounts of propylene carbonate (PC) and dimethoxyethane (DME), which are solvents for the battery. And each is measured,
It was confirmed that the pore inlet diameter was reduced by performing the pore inlet diameter adjusting process. Table 1 shows the results. The re-grinding time was 2 hours and 20 hours.

【００２３】[0023]

【表１】 [Table 1]

【００２４】表１に示すように、粒径６．２μｍの微粒
子表面の細孔入口径調整処理後の難黒鉛化性炭素粒子を
再粉砕すると、再粉砕時間２時間で平均微粒子径が半分
の３．１μｍとなり、２０時間で更に１．６μｍとなっ
た。いずれも、再粉砕によって細孔容積はほとんど変わ
らないが、ＰＣ及びＤＭＥの吸着量が増大したことが判
る。つまり、再粉砕前には細孔入口の径が有機溶媒であ
るＰＣ及びＤＭＥが実質的に通過不可能な径に絞られて
おり、ＰＣ及びＤＭＥは細孔内に侵入できなかったが、
再粉砕によって平均粒径を半分以下に粉砕したときに新
たに入口が生じて、ＰＣ及びＤＭＥが細孔内に侵入でき
るようになったものと理解される。そして、このときの
ＰＣ及びＤＭＥの吸着量は２．５〜２４．９重量％であ
った。 As shown in Table 1, when the non-graphitizable carbon particles having been subjected to the pore inlet diameter adjustment treatment on the surface of the fine particles having a particle diameter of 6.2 μm were crushed again, the average fine particle diameter was halved in 2 hours of crushing time. It became 3.1 μm and further became 1.6 μm in 20 hours. In each case, the pore volume hardly changed by re-milling, but it can be seen that the adsorption amounts of PC and DME increased. In other words, before re-grinding, the pore inlet diameter is
PC and DME are narrowed to a diameter that cannot substantially pass through , and PC and DME cannot enter the pores.
It is understood that a new inlet is created when the average particle size is reduced to less than half by re-grinding, so that PC and DME can enter the pores. And at this time
The adsorption amount of PC and DME is 2.5 to 24.9% by weight.
Was.

【００２５】次に、上記負極材を用いたテストセル（評
価セル）を製作し、充放電容量試験により本発明の負極
材の性能を評価した。Next, a test cell (evaluation cell) using the above-described negative electrode material was manufactured, and the performance of the negative electrode material of the present invention was evaluated by a charge / discharge capacity test.

【００２６】図１はテストセルの構造で、１は本発明の
炭素負極材を用いた電極、２は対極として用いるリチウ
ム電極、３は両極間のセパレータ、４は電解液、５はリ
チウム電極でなる参照電極である。FIG. 1 shows the structure of a test cell, 1 is an electrode using the carbon anode material of the present invention, 2 is a lithium electrode used as a counter electrode, 3 is a separator between both electrodes, 4 is an electrolyte, and 5 is a lithium electrode. Reference electrode.

【００２７】負極材１は、細孔入口径の調整処理を終え
た難黒鉛化性炭素粒子に対して結合剤として１０重量％
のポリフッ化ビニリデンを加え、ペースト化剤としてジ
メチルホルムアミドを加えてペースト状にした後、直径
１０ｍｍ、厚さ０．５ｍｍのコイン型にプレス成型して
用いた。The negative electrode material 1 was used as a binder in an amount of 10% by weight with respect to the non-graphitizable carbon particles having been subjected to the pore diameter adjustment process.
Of polyvinylidene fluoride from
After adding methylformamide to form a paste, it was pressed into a coin having a diameter of 10 mm and a thickness of 0.5 mm and used.

【００２８】電解液には、プロピレンカーボネートとジ
メトキシエタンの１：１混合溶液からなる有機溶媒に、
支持電解質として過塩素酸リチウム（ＬｉＣｌＯ４）を
１．０ｍｏｌ／ｌ加えたものを用いた。In the electrolyte, an organic solvent consisting of a 1: 1 mixed solution of propylene carbonate and dimethoxyethane was used.
As the supporting electrolyte, one to which 1.0 mol / l of lithium perchlorate (LiClO 4 ) was added was used.

【００２９】製作したテストセルについて充放電試験を
行った際の電流電位変化の概念図を図２に示す。なお、
厳密に言うと、このテストセルにおいては炭素極は正極
となり、炭素極へのリチウムのドーピングは放電という
ことになるが、実電池に合わせて便宜上この過程を充電
と呼ぶこととし、これとは逆に炭素極からリチウムを取
出す過程を放電と呼ぶこととする。FIG. 2 is a conceptual diagram showing a change in current potential when a charge / discharge test is performed on the manufactured test cell. In addition,
Strictly speaking, in this test cell, the carbon electrode is a positive electrode, and lithium doping of the carbon electrode is discharge, but for convenience, this process is called charging for the actual battery, and conversely. The process of extracting lithium from the carbon electrode is referred to as discharge.

【００３０】図２に示すように、先ず充電を行った。負
極の炭素電極の通電前の初期電位は、リチウム参照電極
に対して約１．５Ｖであり、電流密度０．５３ｍＡ／ｃ
ｍ２の定電流で通電を開始すると、電極電位は徐々に下
降した。電極電位が０ｍＶに達した時に，定電流から定
電位に切換えて電流密度が微小になったときに電源を切
り、電位の回復が２時間休止後に２０ｍＶ程度以下の時
を充電終了とした。As shown in FIG. 2, charging was first performed. The initial potential of the negative electrode before energization is about 1.5 V with respect to the lithium reference electrode, and the current density is 0.53 mA / c.
When current supply was started at a constant current of m 2 , the electrode potential gradually decreased. When the electrode potential reached 0 mV, the power was turned off when the current density was reduced by switching from the constant current to the constant potential, and the charging was terminated when the potential recovery was about 20 mV or less after a pause of 2 hours.

【００３１】そして、２時間の休止の後、放電を行っ
た。放電は、０．５３ｍＡ／ｃｍ2 の定電流で開始し、
電位が１．５Ｖに達した時点で定電位に切換え、電流密
度が０．０５ｍＡ／ｃｍ2 以下になった時点で放電終了
とした。このときの充放電容量等の測定結果を表２に示
す。なお、充放電容量は炭素１ｇ当たりの容量であり、
以後の実施例についても同様である。After a pause of 2 hours, discharge was performed. The discharge starts with a constant current of 0.53 mA / cm 2 ,
When the potential reached 1.5 V, the potential was switched to the constant potential, and when the current density became 0.05 mA / cm 2 or less, the discharge was terminated. Table 2 shows the measurement results of the charge / discharge capacity and the like at this time. The charge / discharge capacity is a capacity per 1 g of carbon,
The same applies to the following embodiments.

【００３２】実施例２ 原料としてフラン樹脂（日立化成工業（株）製 ＶＦ−
３０７）を用い、これを６００℃で乾留した後、窒素気
流中８００℃で１時間熱処理して難黒鉛化性炭素を得
た。次いで、実施例１と同様にして粉砕，細孔入口径調
整処理を行い、電極を作成して充放電試験を行った。こ
のときのＰＣ及びＤＭＥの吸着量、充放電容量等の測定
結果を表２に示す。 Example 2 A furan resin (VF-manufactured by Hitachi Chemical Co., Ltd.) was used as a raw material.
307), which was carbonized at 600 ° C.
Heat treatment at 800 ° C for 1 hour in flow to obtain non-graphitizable carbon
Was. Then, in the same manner as in Example 1, pulverization and pore inlet diameter adjustment
The electrode was prepared, and a charge / discharge test was performed. This
Of PC and DME adsorption amount, charge / discharge capacity, etc.
Table 2 shows the results.

【００３３】実施例３ 原料としてヤシガラチャーを用い、これを希塩酸で洗浄
して脱アルカリ処理を行い、水洗して乾燥した後、窒素
気流中８００℃で１時間熱処理して難黒鉛化性炭素を得
た。次いで、実施例１と同様にして粉砕，細孔入口径調
整処理を行い、電極を作成して充放電試験を行った。こ
のときのＰＣ及びＤＭＥの吸着量，充放電容量等の測定
結果を表２に示す。 EXAMPLE 3 Coconut garnish was used as a raw material, and this was washed with dilute hydrochloric acid.
To remove alkali, wash with water and dry.
Heat treatment at 800 ° C for 1 hour in air stream to obtain non-graphitizable carbon
Was. Then, in the same manner as in Example 1, pulverization and pore inlet diameter adjustment
The electrode was prepared, and a charge / discharge test was performed. This
Of adsorption amount of PC and DME, charge / discharge capacity, etc.
Table 2 shows the results.

【００３４】[0034]

【表２】 [Table 2]

【００３５】比較例１〜３ 実施例１〜３において、細孔入口径調整処理を行わなか
ったこと以外は同様にして電極を作成し、充放電試験を
行った。このときのＰＣ及びＤＭＥの吸着量，充放電容
量等の測定結果を表３に示す。Comparative Examples 1 to 3 Electrodes were prepared in the same manner as in Examples 1 to 3, except that the pore inlet diameter adjusting treatment was not performed, and a charge / discharge test was performed. Table 3 shows the measurement results of the amounts of PC and DME adsorbed and the charge / discharge capacity at this time.

【００３６】[0036]

【表３】 [Table 3]

【００３７】表２及び表３に示す結果から、細孔入口径
調整処理を行って細孔の入口径を絞り、該細孔入口径
を、リチウムイオンが通過可能で、かつ、電解液中の有
機溶媒が実質的に通過不可能な径、すなわち、リチウム
イオンの通過により充放電が可能で、かつ、放電容量低
下の原因となる有機溶媒が細孔内に侵入して吸着するこ
とを防止できるような径とし、負極となる難黒鉛化性炭
素への有機溶媒の吸着量を実質的に零、すなわち、電解
液中の有機溶媒がみかけ上吸着不可能にすることによ
り、放電容量を向上させて不可逆容量を極小化させるこ
とができる。From the results shown in Tables 2 and 3, a pore inlet diameter adjusting process is performed to narrow the pore inlet diameter, and the pore inlet diameter is adjusted so that lithium ions can pass therethrough and that A diameter through which the organic solvent cannot substantially pass, that is, charging and discharging are possible by passing lithium ions, and it is possible to prevent the organic solvent that causes a decrease in discharge capacity from entering the pores and being adsorbed. With such a diameter, the adsorption amount of the organic solvent to the non-graphitizable carbon that becomes the negative electrode is substantially zero ,
By making the organic solvent in the liquid apparently impossible to adsorb , the discharge capacity can be improved and the irreversible capacity can be minimized.

【００３８】実施例４ フェノール樹脂を５５０℃で乾留した後、窒素気流中９
００℃で１時間熱処理し、次いで、これを粉砕して難黒
鉛化性炭素微粒子を得た。次に、上記炭素微粒子表面の
細孔入口径を調整するための処理として、熱分解性炭化
水素蒸気として、トルエン，ベンゼン，ブタンを用い
て、実施例１と同様に炭素の析出処理を施した。次い
で、実施例１と同様に図１のテストセルにて性能試験を
行った。この結果を表４に示す。Example 4 A phenol resin was carbonized at 550 ° C.
Heat treatment was performed at 00 ° C. for 1 hour, and then pulverized to obtain non-graphitizable carbon fine particles. Next, as a treatment for adjusting the pore entrance diameter on the surface of the carbon fine particles, a precipitation treatment of carbon was performed in the same manner as in Example 1, using toluene, benzene, and butane as the thermally decomposable hydrocarbon vapor. . Next, a performance test was performed using the test cell of FIG. Table 4 shows the results.

【００３９】[0039]

【表４】 [Table 4]

【００４０】実施例５ 実施例４と同様にして得た難黒鉛化性炭素微粒子の細孔
入口径を調整するため、析出処理を液状の熱分解性炭化
水素として、２，４ーキシレノール，キノリン，クレオ
ソートを用いて行った。すなわち、上記炭化水素を添着
して、９００℃で１時間熱処理した。炭素析出処理にお
ける添加量は、それぞれ、１０重量％，５重量％，１５
重量％であった。Example 5 In order to adjust the pore entrance diameter of the non-graphitizable carbon fine particles obtained in the same manner as in Example 4, the deposition treatment was carried out using a liquid pyrolytic hydrocarbon as 2,4-xylenol, quinoline, Performed using creosote. That is, the above-mentioned hydrocarbon was impregnated and heat-treated at 900 ° C. for 1 hour. The amounts added in the carbon deposition treatment were 10% by weight, 5% by weight, and 15% by weight, respectively.
% By weight.

【００４１】次いで、実施例１と同様に図１のテストセ
ルにて性能試験を行った。この結果を表５に示す。Next, a performance test was performed using the test cell of FIG. Table 5 shows the results.

【００４２】[0042]

【表５】 [Table 5]

【００４３】比較例４ 実施例４と同様にして難黒鉛化性炭素微粒子を得た。炭
素微粒子表面の細孔入口径を調整する処理を施さない以
外は実施例１と同様にして電極を作成し、ＰＣ及びＤＭ
Ｅの吸着量，充放電容量等の測定結果を表６に示す。Comparative Example 4 In the same manner as in Example 4, hardly graphitizable carbon fine particles were obtained. An electrode was prepared in the same manner as in Example 1 except that the treatment for adjusting the pore entrance diameter on the surface of the carbon fine particles was not performed, and PC and DM were prepared.
Table 6 shows the measurement results of the adsorption amount of E, the charge / discharge capacity, and the like.

【００４４】[0044]

【表６】 [Table 6]

【００４５】炭素微粒子表面の細孔入口径を調整する処
理を、実施例４においては、トルエン，ベンゼン及びブ
タン等の蒸気状の熱分解性炭化水素を用い、実施例５に
おいては、キシレノール，キノリン及びクレオソート等
の液状の熱分解性炭化水素を用いたが、いずれも、比較
例４と比べてＰＣ及びＤＭＥ吸着量が殆ど零となってお
り、充電量が大きく、放電量は大幅に大きくなった。The treatment for adjusting the pore entrance diameter on the surface of the carbon fine particles was carried out in Example 4 using a thermally decomposable hydrocarbon in the form of vapor such as toluene, benzene and butane. In Example 5, xylenol and quinoline were used. And the use of liquid pyrolytic hydrocarbons such as creosote, etc., in both cases, the PC and DME adsorption amounts were almost zero compared to Comparative Example 4, the charge amount was large, and the discharge amount was significantly large. became.

【００４６】実施例６ 次に、実際にリチウム二次電池を製作し性能を試験し
た。図３は試験用のコイン型リチウム二次電池で、リチ
ウムイオンを含有する有機溶媒を電解質として含浸した
セパレーター１１の両側に、ＬｉＣｏＯ2 を主成分とす
る正極１２と、難黒鉛化性炭素からなる負極１３とを対
向配置するとともに、これらの周囲を、缶体１４，キャ
ップ１５及び該缶体１４とキャップ１５とを絶縁状態で
固着するパッキング１６で覆うようにして形成したもの
である。Example 6 Next, a lithium secondary battery was actually manufactured and its performance was tested. FIG. 3 shows a coin-type lithium secondary battery for testing, comprising a positive electrode 12 containing LiCoO 2 as a main component and non-graphitizable carbon on both sides of a separator 11 impregnated with an organic solvent containing lithium ions as an electrolyte. The negative electrode 13 is disposed so as to face the negative electrode 13 and the periphery thereof is covered with a can 16, a cap 15, and a packing 16 for fixing the can 14 and the cap 15 in an insulated state.

【００４７】負極１３には、実施例１で作成した炭素電
極を用いた。正極１２には、コバルト酸リチウム１０ｇ
にグラファイト１ｇ，ポリテトラフルオロエチレン１ｇ
を加えて良く混合した後、その２ｇを採り直径１０ｍｍ
にプレス成型したものを用いた。セパレータ１１は、ポ
リプロピレンの多孔性膜とした。電解液には、ＰＣ＋Ｄ
ＭＥ（１：１）に、支持電解質としてＬｉＣｌＯ４を
１．０ｍｏｌ／ｌの濃度に加えたものを用いた。As the negative electrode 13, the carbon electrode prepared in Example 1 was used. The positive electrode 12 has 10 g of lithium cobalt oxide.
1g of graphite, 1g of polytetrafluoroethylene
, And mix well, then take 2 g and take 10 mm in diameter.
What was press-molded was used. The separator 11 was a porous film of polypropylene. PC + D for electrolyte
ME (1: 1) obtained by adding LiClO 4 to a concentration of 1.0 mol / l as a supporting electrolyte was used.

【００４８】上記リチウム二次電池により、電流密度
０．５３ｍＡ／ｃｍ2 の定電流で、電圧が３．５Ｖに達
するまで充電を行った後、同電流密度で放電終止電圧を
１．０Ｖとして放電を行った。この操作を繰返して充放
電容量の変化を測定した。この結果を表７に示す。Using the above lithium secondary battery, charging was performed at a constant current of 0.53 mA / cm 2 until the voltage reached 3.5 V, and then discharge was performed at the same current density with a discharge end voltage of 1.0 V. Was done. This operation was repeated to measure the change in charge / discharge capacity. Table 7 shows the results.

【００４９】[0049]

【表７】 [Table 7]

【００５０】なお、本発明においては、リチウム二次電
池自体の形状、例えば缶体１４やキャップ１５の形状、
その大きさ、正極１２に使用する材料、電解質を構成す
る有機溶媒の種類等は、特に限定されるものではなく、
リチウム二次電池の使用状態、電池容量等の諸条件に応
じて任意に選定することが可能である。In the present invention, the shape of the lithium secondary battery itself, for example, the shape of the can 14 and the cap 15,
The size, the material used for the positive electrode 12, the type of organic solvent constituting the electrolyte, and the like are not particularly limited.
It can be arbitrarily selected according to various conditions such as a use state of the lithium secondary battery and a battery capacity.

【００５１】比較例５ 比較例１で作成した炭素電極を負極として、実施例６と
同様にしてコイン型のリチウム二次電池を作成し、繰返
し充放電容量の変化を測定した結果を表８に示す。Comparative Example 5 Using the carbon electrode prepared in Comparative Example 1 as a negative electrode, a coin-type lithium secondary battery was prepared in the same manner as in Example 6, and the results of repeatedly measuring the change in charge / discharge capacity are shown in Table 8. Show.

【００５２】[0052]

【表８】 [Table 8]

【００５３】実施例６は、本発明による炭素微粒子表面
の細孔入口径を調整する処理を施した炭素負極を用いた
電池であり、処理をしていない比較例５に比べて、大き
な充放電容量を有し、しかも、繰返し充放電特性も優れ
ている。Example 6 is a battery using a carbon anode treated to adjust the pore entrance diameter on the surface of carbon fine particles according to the present invention, and has a larger charge / discharge as compared with Comparative Example 5 not treated. It has a capacity and excellent repetition charge / discharge characteristics.

【００５４】[0054]

【発明の効果】以上説明したように、本発明は、炭素負
極材を構成する難黒鉛化性炭素の細孔入口径を、リチウ
ム二次電池の電解液中のリチウムイオンが通過可能で、
かつ、電解液中の有機溶媒が実質的に通過不可能な径と
したから、これをリチウム二次電池の負極として用いる
ことにより、リチウム二次電池の電解液として用いる有
機溶媒が負極の難黒鉛化性炭素に吸着して放電容量を低
下させることを防止でき、同時に充電容量も増加させ、
放電効率を高めてリチウム二次電池の電池容量を大幅に
向上させることができる。As described above, according to the present invention, the onset Ming, carbon negative
The lithium ion in the electrolyte of the lithium secondary battery can pass through the pore inlet diameter of the non-graphitizable carbon constituting the electrode material ,
In addition, since the diameter of the organic solvent in the electrolyte is substantially not allowed to pass therethrough, by using this as a negative electrode of the lithium secondary battery, the organic solvent used as the electrolyte of the lithium secondary battery can be made of graphite having a negative electrode. Can be prevented from lowering the discharge capacity by being adsorbed on the carbon,
Discharge efficiency can be increased, and the battery capacity of the lithium secondary battery can be significantly improved.

【図面の簡単な説明】[Brief description of the drawings]

【図１】 実施例及び比較例で製作したテストセルの断
面図である。FIG. 1 is a sectional view of a test cell manufactured in an example and a comparative example.

【図２】 実施例１で製作したテストセルの充放電試験
の際の電流電位変化の概念図である。FIG. 2 is a conceptual diagram of a change in current potential during a charge / discharge test of a test cell manufactured in Example 1.

【図３】 リチウム二次電池の一例を示す断面図であ
る。FIG. 3 is a cross-sectional view illustrating an example of a lithium secondary battery.

【符号の説明】 １…本発明の炭素負極材を用いた電極、２…対極として
用いるリチウム電極、３…セパレータ、４…電解液、５
…参照電極、１１…セパレーター、１２…正極、１３…
負極、１４…缶、１５…キャップ、１６…パッキング[Description of Signs] 1 ... electrode using carbon negative electrode material of the present invention, 2 ... lithium electrode used as counter electrode, 3 ... separator, 4 ... electrolyte, 5
... Reference electrode, 11 ... Separator, 12 ... Positive electrode, 13 ...
Negative electrode, 14 ... can, 15 ... cap, 16 ... packing

───────────────────────────────────────────────────── フロントページの続き (72)発明者 若泉 章 山梨県北巨摩郡高根町下黒沢3054−３ 日本酸素株式会社内 (58)調査した分野(Int.Cl.6，ＤＢ名) H01M 4/02 H01M 4/58 H01M 10/40────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Akira Wakaizumi 3054-3 Shimokurosawa, Takane-machi, Kita-Koma District, Yamanashi Prefecture Inside Nippon Sanso Corporation (58) Field surveyed (Int.Cl. 6 , DB name) H01M 4/02 H01M 4/58 H01M 10/40

Claims (18)

(57)【特許請求の範囲】(57) [Claims] 【請求項１】 リチウム二次電池用の炭素負極材におい
て、炭素負極材を構成する難黒鉛化性炭素の微粒子表面
の細孔入口径を、リチウム二次電池の電解液中のリチウ
ムイオンが通過可能で、かつ、電解液中の有機溶媒が実
質的に通過不可能な径としたことを特徴とするリチウム
二次電池用の炭素負極材。In a carbon negative electrode material for a lithium secondary battery, lithium ions in an electrolyte of a lithium secondary battery pass through a pore entrance diameter on the surface of fine particles of non-graphitizable carbon constituting the carbon negative electrode material. A carbon negative electrode material for a lithium secondary battery, wherein the diameter of the carbon negative electrode material is made possible and the diameter of the organic solvent in the electrolyte solution cannot be substantially passed. 【請求項２】 前記難黒鉛化性炭素の微粒子は、その内
部に電解液中の有機溶媒を吸着できる細孔があり、該難
黒鉛化性炭素の表面には熱分解炭素が析出しており、そ
の結果前記細孔は、電解液中のリチウムイオンがドープ
及び脱ドープ可能であるとともに電解液中の有機溶媒が
みかけ上吸着不可能であることを特徴とする請求項１記
載のリチウム二次電池用の炭素負極材。Wherein fine particles of the hardly graphitizable carbon, among the
There are pores in the part that can adsorb the organic solvent in the electrolyte,
Pyrolytic carbon is deposited on the surface of the graphitizable carbon,
As a result, the pores are doped with lithium ions in the electrolyte.
And undoped, and the organic solvent in the electrolyte is
The carbon anode material for a lithium secondary battery according to claim 1, wherein the carbon anode material is apparently impossible to adsorb . 【請求項３】 前記難黒鉛化性炭素の微粒子は、平均粒
径を半分以下に粉砕したときの電解液中の有機溶媒の吸
着量が２．５〜２４．９重量％であることを特徴とする
請求項１又は２記載のリチウム二次電池用の炭素負極
材。3. The fine particles of non-graphitizable carbon are average particles.
Absorption of organic solvent in electrolyte when crushed to less than half the diameter
Characterized in that the applied amount is 2.5 to 24.9% by weight.
The carbon negative electrode material for a lithium secondary battery according to claim 1 . 【請求項４】 前記難黒鉛化性炭素の微粒子は、結合剤
とペースト化剤とを添加してプレス成型されていること
を特徴とする請求項１乃至３のいずれか１項記載のリチ
ウム二次電池用の炭素負極材。 4. The method according to claim 1, wherein the fine particles of the non-graphitizable carbon are a binder.
And press-molding
The carbon negative electrode material for a lithium secondary battery according to any one of claims 1 to 3, characterized in that : 【請求項５】 前記難黒鉛化性炭素の微粒子の表面に析
出した熱分解炭素は、熱分解性炭化水素の熱分解法によ
り析出されたものであることを特徴とする請求項２記載
のリチウム二次電池用の炭素負極材。 5. The method according to claim 5, wherein the fine particles of non-graphitizable carbon are deposited on the surface of the fine particles.
The released pyrolytic carbon is obtained by pyrolysis of pyrolytic hydrocarbons.
3. The composition according to claim 2, wherein the substance is deposited.
Negative electrode material for lithium secondary batteries. 【請求項６】 前記熱分解性炭化水素は、トルエン、ベ
ンゼン、ブタン、２，４−キシレノール、キノリン、ク
レオソートのいずれかであることを特徴とする請求項５
記載のリチウム二次電池用の炭素負極材。 6. The thermally decomposable hydrocarbon is toluene,
Senzen, butane, 2,4-xylenol, quinoline,
6. The method according to claim 5, wherein the material is any one of Leosote.
The carbon negative electrode material for a lithium secondary battery according to the above. 【請求項７】 前記電解液中の有機溶媒は、プロピレン
カーボネートとジメトキシエタンの１：１混合液である
ことを特徴とする請求項１乃至６のいずれか１項記載の
リチウム二次電池用の炭素負極材。 7. The organic solvent in the electrolyte is propylene.
1: 1 mixture of carbonate and dimethoxyethane
The method according to any one of claims 1 to 6, wherein
Carbon anode material for lithium secondary batteries. 【請求項８】 前記電解液中の支持電解質は、過塩素酸
リチウムであることを特徴とする請求項１乃至７のいず
れか１項記載のリチウム二次電池用の炭素負極材。 8. The supporting electrolyte in the electrolyte is perchloric acid.
8. The method according to claim 1, wherein said lithium is lithium.
The carbon negative electrode material for a lithium secondary battery according to claim 1. 【請求項９】 リチウム二次電池用の炭素負極材の製造
方法において、炭素 負極材を構成する難黒鉛化性炭素の
微粒子表面の細孔入口径を、リチウム二次電池の電解液
中のリチウムイオンが通過可能で、かつ、電解液中の有
機溶媒が実質的に通過不可能な径に形成することを特徴
とするリチウム二次電池用の炭素負極材の製造方法。 9. Production of a carbon anode material for a lithium secondary battery
In the method, the non- graphitizable carbon constituting the carbon anode material is
The pore inlet diameter on the surface of the fine particles is adjusted to the electrolyte of the lithium secondary battery.
Lithium ions can pass through and the electrolyte
Characterized in that the solvent solvent is formed to a diameter that is substantially impermeable.
Of producing a carbon negative electrode material for a lithium secondary battery. 【請求項１０】 前記難黒鉛化性炭素の微粒子に、加熱
下で熱分解性炭化水素を接触せしめて微粒子表面に熱分
解炭素を析出させ、電解液中の有機溶媒を吸着できる微
粒子の細孔を、電解液中のリチウムイオンがドープ及び
脱ドープ可能であるとともに電解液中の有機溶媒がみか
け上吸着不可能に形成することを特徴とする請求項９記
載のリチウム二次電池用の炭素負極材の製造方法。 10. The method according to claim 10, wherein the fine particles of non-graphitizable carbon are heated.
Contact the pyrolytic hydrocarbon under the
Fine particles that can precipitate carbon dioxide and adsorb organic solvents in the electrolyte
The pores of the particles are doped with lithium ions in the electrolyte and
Dedopable and organic solvent in electrolyte
10. The apparatus according to claim 9, wherein the suction port is formed so as not to be adsorbed.
The method for producing a carbon negative electrode material for a lithium secondary battery described above. 【請求項１１】 前記難黒鉛化性炭素の微粒子は、フェ
ノール樹脂又はフラン樹脂を乾留した後熱処理し、次い
で粉砕したものであることを特徴とする請求項９又は１
０記載のリチウム二次電池用の炭素負極材の製造方法。 11. The fine particles of non-graphitizable carbon are made of ferrite.
After heat-drying the ethanol or furan resin,
9. A crushed product according to claim 9 or claim 1.
0. The method for producing a carbon negative electrode material for a lithium secondary battery according to 0. 【請求項１２】 前記フェノール樹脂の熱処理温度は、
８００〜９００℃であることを特徴とする請求項１１記
載のリチウム二次電池用の炭素負極材の製造方法。 12. The heat treatment temperature of the phenol resin is as follows:
12. The temperature of 800 to 900 [deg.] C.
The method for producing a carbon negative electrode material for a lithium secondary battery described above. 【請求項１３】 前記難黒鉛化性炭素の微粒子は、ヤシ
ガラチャーを脱アルカリした後熱処理し、次いで粉砕し
たものであることを特徴とする請求項９又は１０記載の
リチウム二次電池用の炭素負極材の製造方法。 13. The method according to claim 13, wherein the fine particles of non-graphitizable carbon are coconut.
After the alkali is dealkalized, heat treated and then ground
The method according to claim 9 or 10, wherein
A method for producing a carbon negative electrode material for a lithium secondary battery. 【請求項１４】 前記ヤシガラチャーの脱アルカリは、
希塩酸で洗浄することを特徴とする請求項１３記載のリ
チウム二次電池用の炭素負極材の製造方法。 14. The dealkalization of the coconut pulp is as follows:
14. The method according to claim 13, wherein the substrate is washed with dilute hydrochloric acid.
A method for producing a carbon negative electrode material for a lithium secondary battery. 【請求項１５】 前記難黒鉛化性炭素の微粒子は、結合
剤とペースト化剤とを添加してプレス成型することを特
徴とする請求項９乃至１４のいずれか１項記載のリチウ
ム二次電池用の炭素負極材の製造方法。 15. The fine particles of non-graphitizable carbon are bonded to each other.
Press molding with the addition of paste and paste.
15. Lichium according to any one of claims 9 to 14, characterized in that
A method for producing a carbon negative electrode material for a secondary battery. 【請求項１６】 前記熱分解性炭化水素は、トルエン、
ベンゼン、ブタン、２，４−キシレノール、キノリン、
クレオソートのいずれかであることを特徴とする請求項
１０記載のリチウム二次電池用の炭素負極材の製造方
法。 16. The thermally decomposable hydrocarbon is toluene,
Benzene, butane, 2,4-xylenol, quinoline,
Claims being one of creosote
10. A method for producing a carbon anode material for a lithium secondary battery according to item 10.
Law. 【請求項１７】 前記電解液中の有機溶媒は、プロピレ
ンカーボネートとジメトキシエタンの１：１混合液であ
ることを特徴とする請求項９乃至１６のいずれか１項記
載のリチウム二次電池用の炭素負極材の製造方法。 17. The organic solvent in the electrolytic solution is propylene
1: 1 mixture of carbonate and dimethoxyethane
17. The method according to claim 9, wherein:
The method for producing a carbon negative electrode material for a lithium secondary battery described above. 【請求項１８】 前記電解液中の支持電解質は、過塩素
酸リチウムであることを特徴とする請求項９乃至１７の
いずれか１項記載のリチウム二次電池用の炭素負極材の
製造方法。 18. A supporting electrolyte in the electrolytic solution is perchlorine.
18. A lithium oxide according to claim 9, wherein
The carbon negative electrode material for a lithium secondary battery according to any one of claims 1 to 4.
Production method.
JP6021344A 1994-02-18 1994-02-18 Carbon negative electrode material for lithium secondary battery and method for producing the same Expired - Fee Related JP2844302B2 (en)

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