JP2001357849A - Negative electrode material for lithium secondary battery, its manufacturing method, and lithium secondary battery - Google Patents

Negative electrode material for lithium secondary battery, its manufacturing method, and lithium secondary battery

Info

Publication number
JP2001357849A
JP2001357849A JP2000176797A JP2000176797A JP2001357849A JP 2001357849 A JP2001357849 A JP 2001357849A JP 2000176797 A JP2000176797 A JP 2000176797A JP 2000176797 A JP2000176797 A JP 2000176797A JP 2001357849 A JP2001357849 A JP 2001357849A
Authority
JP
Japan
Prior art keywords
negative electrode
graphite
secondary battery
lithium secondary
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.)
Withdrawn
Application number
JP2000176797A
Other languages
Japanese (ja)
Inventor
Koji Kuroda
孝二 黒田
Hiroaki Amahashi
弘明 天橋
Teruhiro Tsurumoto
照啓 鶴本
Taro Kono
太郎 河野
Tsutomu Sugiura
勉 杉浦
Takeshi Hamada
健 濱田
Hiromasa Shoji
浩雅 莊司
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nippon Steel Corp
SEC Corp
Original Assignee
Nippon Steel Corp
SEC Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Nippon Steel Corp, SEC Corp filed Critical Nippon Steel Corp
Priority to JP2000176797A priority Critical patent/JP2001357849A/en
Publication of JP2001357849A publication Critical patent/JP2001357849A/en
Withdrawn legal-status Critical Current

Links

Classifications

    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Abstract

PROBLEM TO BE SOLVED: To provide a negative electrode material having a discharge capacity of the highest level of flake graphite such as natural graphite or the discharge capacity equivalent to the theoretical capacity depending on graphite structure, and solving such a problem of the flake graphite that irreversible capacity caused by side reaction in the initial stage of charge is large and discharge capacity in use under high charge/discharge current is low, and to provide the manufacturing method of the negative electrode material, and industrially provide a lithium secondary battery using the negative electrode material. SOLUTION: A carbon material is obtained by heat treating a kneaded material of graphite prepared by treating carbon deposited in a cooling process of molten state metal and carbon and having a carbon content of 90 mass percent or more and a carbonaceous binder, and this carbon material having a specified range of average particle size and a specified range of tap densities is manufactured as the negative electrode material for the lithium secondary battery, and the lithium secondary battery is manufactured by using this carbon material as the negative electrode active material.

Description

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

【０００１】[0001]

【発明の属する技術分野】本発明は、リチウムの挿入、
脱離反応を利用するリチウム二次電池およびこれに用い
られる負極活物質に関するものである。さらに詳しく
は、放電容量が大きく、且つ、充放電時の容量ロスの少
ない高性能なリチウム二次電池およびこれに用いられる
負極活物質に関するものである。FIELD OF THE INVENTION The present invention relates to lithium insertion,
The present invention relates to a lithium secondary battery utilizing an elimination reaction and a negative electrode active material used for the lithium secondary battery. More specifically, the present invention relates to a high-performance lithium secondary battery having a large discharge capacity and a small capacity loss at the time of charging and discharging, and a negative electrode active material used for the same.

【０００２】[0002]

【従来の技術】黒鉛等の炭素材料を負極として用いるリ
チウム二次電池は、金属リチウムを用いた場合に問題と
なる充電時のデンドライト生成がなく、信頼性の高い電
池であることから活発に研究されている。特に、炭素材
料として黒鉛を用いた場合は、充電時にリチウムが黒鉛
層間に挿入した、いわゆる黒鉛層間化合物を形成するこ
とにより、充電時にリチウムが負極中に吸蔵され、負極
材料に金属リチウムを用いた際に問題となるデンドライ
トの生成が抑止され、かつ放電電位も金属リチウムを用
いた場合に比べ、０〜０．１Ｖ程度高いに過ぎないため
に、高起電力が得られるといった優れた特性を持つ。2. Description of the Related Art A lithium secondary battery using a carbon material such as graphite as a negative electrode does not generate dendrite during charging, which is a problem when lithium metal is used, and is a highly reliable battery. Have been. In particular, when graphite was used as a carbon material, lithium was inserted between graphite layers during charging, forming a so-called graphite intercalation compound, lithium was occluded in the negative electrode during charging, and metallic lithium was used as the negative electrode material. In this case, the generation of dendrite, which is a problem at the time, is suppressed, and the discharge potential is only about 0 to 0.1 V higher than the case where metallic lithium is used. .

【０００３】ただし、黒鉛材料と分類される炭素は、そ
の形状、構造、組織は多様であり、この違いが電極性能
に反映される。However, carbon classified as a graphite material has various shapes, structures and structures, and this difference is reflected in the electrode performance.

【０００４】黒鉛材料として天然黒鉛等の鱗片状黒鉛を
用いた場合、その高度に発達した黒鉛結晶構造により、
以下で述べるメソフェーズ小球体、ピッチ系炭素繊維、
ピッチコークス等を黒鉛化焼成して得られる人造黒鉛に
比べて、高い放電容量が得られることが知られている
（例えば、第４０回電池討論会１Ｄ１４）。しかしなが
ら、これら鱗片状黒鉛においては、初期充電過程におい
て、主として黒鉛層構造端部近傍で進行する副反応に起
因する初期不可逆容量が大きいという問題がある。加え
て、天然黒鉛においては、これらの結晶構造は、炭素網
面層が特定方向への優先配向をしているため、材料中の
リチウムの拡散方向が限定され、しかも、その拡散距離
が非常に長い。従って、大きな充放電電流下で使用した
場合、高い放電容量を得ることは難しく、実用上の制約
を受けるものと思われる。When flaky graphite such as natural graphite is used as a graphite material, its highly developed graphite crystal structure causes
Mesophase small spheres described below, pitch-based carbon fiber,
It is known that a higher discharge capacity can be obtained than artificial graphite obtained by graphitizing and firing pitch coke or the like (for example, 40th Battery Symposium 1D14). However, these flaky graphites have a problem in the initial charging process that the initial irreversible capacity is large due to a side reaction that proceeds mainly near the end of the graphite layer structure. In addition, in natural graphite, these crystal structures are limited in the diffusion direction of lithium in the material because the carbon mesh layer has a preferential orientation in a specific direction, and the diffusion distance is extremely large. long. Therefore, when used under a large charge / discharge current, it is difficult to obtain a high discharge capacity, and it is considered that practical use is restricted.

【０００５】黒鉛材料として、メソフェーズピッチの光
学的異方性相が球状に生成した段階で採取して調製した
メソフェーズ小球体を用いた場合、黒鉛化後の炭素層面
の発達が天然黒鉛に比べて劣ることにより、理論的放電
容量に比べて８０〜８５％程度の放電容量しか得られな
いという問題がある。[0005] When a mesophase sphere obtained by sampling at the stage when the optically anisotropic phase of the mesophase pitch is formed into a spherical shape is used as a graphite material, the carbon layer surface after graphitization is more developed than natural graphite. Due to the inferiority, there is a problem that only a discharge capacity of about 80 to 85% can be obtained as compared with the theoretical discharge capacity.

【０００６】ピッチ系炭素繊維も、超高温の温度領域で
の黒鉛化処理により人造黒鉛としての種々特性を備え、
かつリチウムの拡散方向が繊維外周から内部へ向かって
の多方向、かつ拡散距離が繊維外周から繊維軸までの繊
維径の半分の数μｍ程度と短いため、この炭素繊維を粉
砕した粉末は、拡散係数が他の易黒鉛化性材料と比較し
て大きく、重負荷特性を確認したとの報告（Ｊ．Ｅｌｅ
ｃｔｒｏｃｈｅｍｉ．Ｓｏｃ．，１４２，８，２５６４
（１９９５））もされている。しかし、繊維の形態を維
持するがゆえに、熱処理温度を高くしても、結晶構造の
発達が阻害されて、放電容量が大きくならないこと、繊
維の形態を確保するためのピッチの高純度化処理、繊維
化工程等が必要なため、黒鉛化処理前の段階で他材料と
比較してより多くの製造コストがかかるなどの問題があ
る。[0006] Pitch-based carbon fibers also have various characteristics as artificial graphite by graphitization in an ultra-high temperature range,
In addition, since the diffusion direction of lithium is multi-directional from the outer periphery of the fiber to the inside and the diffusion distance is as short as several μm, which is half the fiber diameter from the outer periphery of the fiber to the fiber axis, the powder obtained by pulverizing this carbon fiber is Reports that the coefficient is large compared to other graphitizable materials and that heavy load characteristics have been confirmed (J. Ele).
trochemi. Soc. , 142, 8, 2564
(1995)). However, since the fiber form is maintained, even if the heat treatment temperature is increased, the development of the crystal structure is hindered, the discharge capacity does not increase, and the pitch is highly purified to secure the fiber form. Since a fiberization step and the like are required, there is a problem that a higher production cost is required compared to other materials before the graphitization treatment.

【０００７】ピッチコークスは、易黒鉛化性材料の部類
に属し、超高温の温度領域での黒鉛化処理により、天然
黒鉛に近い炭素網面層の層間距離に近づくが、コークス
の持つ光学的異方性組織により、天然黒鉛ほど黒鉛化が
発達せず、これらの結晶構造は、炭素網面層が特定方向
への優先配向をしていない。従って、天然黒鉛等の鱗片
状黒鉛に見られた電流密度下の制約は無く、リチウム二
次電池用負極材料として非常に有望な材料であり、これ
まで多くの研究がなされている（例えば、特開昭６３-
１２１２５７号公報、特開平１-２０４３６１号公報、
特開平４-２０６２７６号公報など）。しかしながら、
通常のピッチコークスの超高温処理（２０００〜３００
０℃焼成）品の放電容量は、理論容量（３７２ｍＡｈ／
ｇ）と比較して低い（＜３００ｍＡｈ／ｇ）という問題
が有る。[0007] Pitch coke belongs to the class of graphitizable materials. By graphitization treatment in an ultra-high temperature range, the pitch becomes close to the interlayer distance of a carbon netting layer close to natural graphite. Due to the anisotropic structure, graphitization does not develop as much as natural graphite, and in these crystal structures, the carbon network layer does not have a preferred orientation in a specific direction. Therefore, there is no restriction on the current density observed in flaky graphite such as natural graphite, and it is a very promising material as a negative electrode material for lithium secondary batteries, and many studies have been made so far (for example, Kaisho 63-
JP-A-121257, JP-A-1-204361,
JP-A-4-206276, etc.). However,
Ultra-high temperature processing of ordinary pitch coke (2000 to 300
The discharge capacity of the product (fired at 0 ° C.) is the theoretical capacity (372 mAh /
g) is low (<300 mAh / g).

【０００８】以上のように、リチウム二次電池の負極活
物質として種々の黒鉛材料を用いる際に、高い放電容量
を得るためには、高度に発達した黒鉛層状構造が必要で
ある。この目的で、天然黒鉛等の鱗片状黒鉛を使用した
場合には、初期不可逆容量が大きく、大きな充放電電流
下で良好な特性が得られない等の問題があった。一方、
メソフェーズ小球体、ピッチ系炭素繊維あるいはピッチ
コークスを用いた場合には、その黒鉛構造の発達程度が
鱗片状黒鉛に及ばないため、高い放電容量が得られない
という実用上の問題があった。As described above, when various graphite materials are used as the negative electrode active material of the lithium secondary battery, a highly developed graphite layered structure is required to obtain a high discharge capacity. When flaky graphite such as natural graphite is used for this purpose, there are problems such as a large initial irreversible capacity, and good characteristics cannot be obtained under a large charge / discharge current. on the other hand,
When mesophase spherules, pitch-based carbon fibers or pitch coke is used, the degree of development of the graphite structure is not as high as that of flaky graphite, and there is a practical problem that a high discharge capacity cannot be obtained.

【０００９】[0009]

【発明が解決しようとする課題】本発明は、リチウム二
次電池負極用炭素材料として、天然黒鉛等の鱗片状黒鉛
の最高水準の放電容量もしくは黒鉛構造から決定される
理論容量と同程度の放電容量を持つと共に、かつ充電初
期における副反応に起因する不可逆容量が大きく、大き
な充放電電流下で使用した場合に高い放電容量が得られ
ない等の鱗片状黒鉛の問題を解決した、リチウム二次電
池用負極材料およびその製造方法並びにこれを用いたリ
チウム二次電池を工業的に提供することを目的とする。SUMMARY OF THE INVENTION The present invention relates to a carbon material for a negative electrode of a lithium secondary battery, which has a discharge capacity at the highest level of flake graphite such as natural graphite or a discharge capacity equivalent to a theoretical capacity determined from the graphite structure. Lithium secondary has solved the problem of flaky graphite, such as having a large capacity, and a large irreversible capacity due to side reactions in the initial stage of charging, and a high discharge capacity cannot be obtained when used under a large charge / discharge current. It is an object of the present invention to industrially provide a negative electrode material for a battery, a method for producing the same, and a lithium secondary battery using the same.

【００１０】[0010]

【課題を解決するための手段】本発明者らは、各種黒鉛
材料の粒子形状、生成過程、構造及び粒度等の粉体特性
と電気的物性との関連を鋭意検討した結果、金属と炭素
の溶融状態の冷却過程に析出した炭素を用いて、これを
炭素質バインダーと捏合して捏合物とした後、炭化及び
／または黒鉛化を行うことにより、これをリチウム二次
電池の負極として用いることができ、かつこのリチウム
二次電池負極用材料が高い放電容量を示すと共に、従来
放電容量の大きな鱗片状黒鉛で問題となっていた不可逆
容量が大きい等の問題を大きく改善できる材料であるこ
とを見出した。かかる知見に基づいて、リチウム二次電
池の負極としての電極特性に優れるリチウム二次電池負
極用炭素材料およびその製造方法並びにこれを用いたリ
チウム二次電池を提供するに至った。Means for Solving the Problems The present inventors have conducted intensive studies on the relationship between the powder properties such as the particle shape, formation process, structure, and particle size of various graphite materials and the electrical properties. Using carbon precipitated during the cooling process in the molten state and kneading it with a carbonaceous binder to form a kneaded product, and then performing carbonization and / or graphitization to use this as a negative electrode of a lithium secondary battery And that the material for a negative electrode of a lithium secondary battery exhibits a high discharge capacity, and is a material that can greatly improve problems such as a large irreversible capacity that has been a problem with flaky graphite having a large discharge capacity in the past. I found it. Based on such knowledge, a carbon material for a negative electrode of a lithium secondary battery having excellent electrode characteristics as a negative electrode of a lithium secondary battery, a method for producing the same, and a lithium secondary battery using the same have been provided.

【００１１】即ち、本発明は、（１） 金属と炭素の溶
融状態の冷却過程に析出した炭素を処理して得られる炭
素含有量が９０質量％以上の黒鉛と、炭素質バインダー
との捏合物を、熱処理してなる炭素材料であって、該炭
素材料の平均粒径が５μｍ以上１００μｍ未満、かつ２
０回タップ時のタップ密度が０．７０ｇ／ｃｍ3以上で
あることを特徴とするリチウム二次電池負極用材料、
（２） 前記捏合物の炭素質バインダーが熱処理により
炭素化物になっていることを特徴とする（１）記載のリ
チウム二次電池負極用材料、（３） 前記炭素材料が、
黒鉛化物であることを特徴とする（１）記載のリチウム
二次電池負極用材料、（４） 前記炭素材料の３００回
タップ時のタップ密度が０．８５ｇ／ｃｍ3以上である
ことを特徴とする（１）〜（３）の何れか１項に記載の
リチウム二次電池負極用材料、（５） 前記炭素材料の
炭素含有量が９９質量％以上で、ＢＥＴ法による比表面
積が５ｍ2／ｇ以下であることを特徴とする（１）〜
（４）の何れか１項に記載のリチウム二次電池負極用材
料、（６） 金属と炭素の溶融状態の冷却過程に析出し
た炭素を、炭素含有量が９０質量％以上になるまで高純
度化処理を行った後に、インペラーミル、ジェットミ
ル、レイモンドミルまたはボールミルより選ばれた粉砕
機を用いた粉砕と空気分級を行うことにより得られた黒
鉛と、炭素質バインダーとを捏合し、該捏合物を７００
〜１５００℃で炭化及び／または２４００〜３０００℃
で黒鉛化することを特徴とするリチウム二次電池用負極
用材料の製造方法、（７） 前記金属は、鉄、ニッケ
ル、シリコンおよびコバルトからなる群より選択される
１種または２種以上の金属であることを特徴とする
（６）記載のリチウム二次電池負極用材料の製造方法、
（８） 金属と炭素の溶融状態が、製鉄プロセスの溶融
銑鉄における鉄と炭素の溶融状態であることを特徴とす
る（６）記載のリチウム二次電池負極用材料の製造方
法、（９） 前記黒鉛の平均粒径が３μｍ以上３０μｍ
以下であることを特徴とする（６）〜（８）のいずれか
１項に記載のリチウム二次電池負極用材料の製造方法、
（１０） 前記黒鉛と前記炭素質バインダーを、該炭素
質バインダーの軟化点以上の温度に加熱しながら撹拌、
捏合することを特徴とする（６）〜（９）の何れか１項
に記載のリチウム二次電池負極用材料の製造方法、（１
１） 前記黒鉛と前記炭素質バインダーの捏合割合が、
黒鉛１００質量部に対して、炭素質バインダーが１０〜
７０質量部であることを特徴とする（６）〜（１０）の
何れか１項に記載のリチウム二次電池負極用材料の製造
方法、（１２） 正極活物質と、請求項１〜５の何れか
１項に記載のリチウム二次電池負極用材料を含んでなる
負極活物質と、非水系電解質とを含んでなるリチウム二
次電池である。That is, the present invention relates to (1) a kneaded product of graphite having a carbon content of 90% by mass or more and carbonaceous binder obtained by treating carbon precipitated in a cooling process in a molten state of metal and carbon. Is a carbon material obtained by heat treatment, wherein the average particle size of the carbon material is 5 μm or more and less than 100 μm;
A material for a negative electrode of a lithium secondary battery, wherein a tap density at the time of zero tap is 0.70 g / cm 3 or more,
(2) The material for a negative electrode of a lithium secondary battery according to (1), wherein the carbonaceous binder of the kneaded material has been carbonized by heat treatment. (3) The carbon material is:
(1) The negative electrode material for a lithium secondary battery according to (1), wherein the carbon material has a tap density of 0.85 g / cm 3 or more at 300 taps. (1) The material for a negative electrode of a lithium secondary battery according to any one of (1) to (3), (5) the carbon content of the carbon material is 99% by mass or more, and the specific surface area by a BET method is 5 m 2 / g or less (1)-
(4) The material for a negative electrode of a lithium secondary battery according to any one of (4), (6) High purity of carbon precipitated in a cooling process in a molten state of metal and carbon until the carbon content becomes 90% by mass or more. After performing the carbonization treatment, the graphite obtained by performing pulverization using a pulverizer selected from an impeller mill, a jet mill, a Raymond mill or a ball mill and air classification, and a carbonaceous binder are kneaded, and the kneading is performed. 700 things
Carbonized at ~ 1500C and / or 2400-3000C
(7) a method for producing a negative electrode material for a lithium secondary battery, wherein the metal is one or more metals selected from the group consisting of iron, nickel, silicon and cobalt (6) The method for producing a material for a negative electrode of a lithium secondary battery according to (6),
(8) The method for producing a negative electrode material for a lithium secondary battery according to (6), wherein the molten state of the metal and carbon is a molten state of iron and carbon in the molten pig iron in the iron making process. Average particle size of graphite is 3μm or more and 30μm
The method for producing a material for a negative electrode of a lithium secondary battery according to any one of (6) to (8), wherein:
(10) stirring the graphite and the carbonaceous binder while heating the graphite and the carbonaceous binder to a temperature equal to or higher than the softening point of the carbonaceous binder;
The method for producing a material for a negative electrode of a lithium secondary battery according to any one of (6) to (9), wherein
1) The kneading ratio of the graphite and the carbonaceous binder is:
Carbonaceous binder is 10 to 100 parts by mass of graphite.
The method for producing a material for a negative electrode of a lithium secondary battery according to any one of (6) to (10), wherein the amount is 70 parts by mass; (12) a positive electrode active material; A lithium secondary battery comprising a negative electrode active material comprising the negative electrode material for a lithium secondary battery according to any one of the preceding claims, and a non-aqueous electrolyte.

【００１２】[0012]

【発明の実施の形態】以下に、本発明の内容について具
体的に説明する。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The contents of the present invention will be specifically described below.

【００１３】本発明に係るリチウム二次電池負極用黒鉛
は、金属と炭素の溶融状態の冷却過程で析出した炭素を
処理して得られる炭素含有量が９０質量％以上の黒鉛と
炭素質バインダーを捏合して捏合物とした後熱処理を行
い、これを平均粒径が５μｍ以上１００μｍ未満、かつ
２０回タップ時のタップ密度が０．７０ｇ／ｃｍ3以上
に調製することにより得られるリチウム二次電池負極用
材料である。The graphite for a negative electrode of a lithium secondary battery according to the present invention is obtained by treating a carbon deposited in a cooling process of a molten state of a metal and carbon with a graphite having a carbon content of 90% by mass or more and a carbonaceous binder. Lithium secondary battery obtained by kneading to obtain a kneaded product and then performing heat treatment, adjusting the average particle size to 5 μm or more and less than 100 μm, and adjusting the tap density at the time of 20 taps to 0.70 g / cm 3 or more. It is a negative electrode material.

【００１４】本発明のリチウム二次電池負極用黒鉛の要
件としては、第一に、原料として用いる黒鉛を、人造黒
鉛でありながら天然黒鉛に匹敵する高度な黒鉛構造を得
るために、金属との溶融状態から析出せしめること、第
二に、この黒鉛の炭素含有量を最適な範囲に制御するこ
と、第三に、この黒鉛と炭素質バインダーを捏合して捏
合物とした後に熱処理を行うこと、第四に、これを平均
粒径５μｍ以上１００μｍ未満、かつ２０回タップ時の
タップ密度０．７０ｇ／ｃｍ3以上となる様に調製する
ことにある。以上の第一から第四まですべての要件を合
わせて、以下の記述にて上記要件（１）と呼ぶ。The requirements for the graphite for a negative electrode of a lithium secondary battery according to the present invention are as follows. First, graphite used as a raw material must be mixed with metal in order to obtain an advanced graphite structure comparable to natural graphite while being artificial graphite. Precipitating from a molten state, secondly, controlling the carbon content of the graphite to an optimal range, thirdly, performing a heat treatment after kneading the graphite and the carbonaceous binder into a kneaded product, Fourthly, it is required to adjust the average particle diameter to be not less than 5 μm and less than 100 μm and to have a tap density of 0.70 g / cm 3 at 20 taps. All of the above first to fourth requirements are collectively referred to as requirement (1) in the following description.

【００１５】第一の要件である、原料として用いる黒鉛
を、人造黒鉛でありながら天然黒鉛に匹敵する高度な黒
鉛構造を得るために、金属との溶融状態から析出せしめ
ることに関して説明する。The first requirement, that is, the use of graphite as a raw material in order to obtain an advanced graphite structure comparable to natural graphite while being artificial graphite, will be described in terms of precipitation from a molten state with a metal.

【００１６】本発明のリチウム二次電池負極用材料の原
料として用いる黒鉛は、その生成過程における天然黒鉛
と人造黒鉛という区分において、人造黒鉛に属する。人
造黒鉛を製造する方法としては、炭素を主成分とする原
料を用いて、最終的に２０００℃から３０００℃の高温
で熱処理することが最も一般的である。しかし、この方
法を用いた場合に得られる人造黒鉛では、天然黒鉛に比
較して、黒鉛構造が十分に進行しないため、黒鉛化度は
劣る。一方、金属と炭素の溶融状態の冷却過程で析出し
た炭素は、高度に発達した黒鉛構造をとる。これは、炭
素が溶融相から析出する際、熱力学的に安定な黒鉛を形
成することによる。この高度に発達した黒鉛構造と天然
黒鉛等鱗片状黒鉛における本質的差異の詳細は未だ明ら
かではないが、本発明のリチウム二次電池負極用黒鉛の
電気的性能において、天然黒鉛等の鱗片状黒鉛で問題と
なっていた不可逆容量が大きい等の問題を大きく改善で
きる。これは、天然黒鉛は、黒鉛粒子がほぼ単結晶黒鉛
から成り、かつその結晶配向がほぼ一方向になっている
のに対し、本発明の原料である黒鉛粒子は、黒鉛多結晶
から成っており、しかもその配向が天然黒鉛に比較し
て、多方向になっていることに起因すると推定される。Graphite used as a raw material for the negative electrode material of the lithium secondary battery of the present invention belongs to artificial graphite in the category of natural graphite and artificial graphite in the process of its production. As a method for producing artificial graphite, it is most common to finally perform a heat treatment at a high temperature of 2000 to 3000 ° C. using a raw material containing carbon as a main component. However, in the artificial graphite obtained by using this method, the degree of graphitization is inferior to that of natural graphite because the graphite structure does not proceed sufficiently. On the other hand, carbon precipitated during the cooling process of the molten state of metal and carbon has a highly developed graphite structure. This is due to the formation of thermodynamically stable graphite when carbon precipitates from the molten phase. Although the details of the essential difference between the highly developed graphite structure and the flaky graphite such as natural graphite are not yet clear, the electrical performance of the graphite for the negative electrode of the lithium secondary battery of the present invention shows that the flaky graphite such as natural graphite is used. Thus, problems such as a large irreversible capacity which have been a problem can be greatly improved. This is because, in natural graphite, the graphite particles are substantially made of single-crystal graphite, and the crystal orientation is almost unidirectional, whereas the graphite particles that are the raw material of the present invention are made of graphite polycrystal. Further, it is presumed that the orientation is multi-directional as compared with natural graphite.

【００１７】また、第二の要件である原料として用いる
炭素含有量に関して説明する。The second requirement, that is, the carbon content used as a raw material will be described.

【００１８】リチウム二次電池用負極材料として、黒鉛
を用いることの大きな意義の一つは、充放電過程の化学
変化、即ち、充電時に黒鉛層間にＬｉイオンが挿入され
て、黒鉛層間化合物を形成し、放電時にリチウムイオン
が脱離して、黒鉛に戻る反応における電位が、リチウム
金属とリチウムイオンの変化における電位と同等であ
り、かつ、使用領域の大部分で平坦な放電曲線が得られ
ることである。本発明で得られるリチウム二次電池負極
材料の充放電容量の大部分は、原料として用いる黒鉛に
より得られるものである。即ち、炭素質バインダーと捏
合した後に炭化及び／または黒鉛化を経ることにより、
バインダー成分が炭化または黒鉛化されて、放電容量に
寄与するものの、本発明で得られるリチウム二次電池負
極材料が特徴とする高い放電容量が得られるのは、原料
の黒鉛自体の高い放電容量に起因するものである。従っ
て、原料となる黒鉛の純度が低い場合には、それより得
られる負極材料中の充放電反応に関与する黒鉛の割合が
小さくなり、負極材料として高い放電容量を担うことは
できない。仮に、負極材料中の黒鉛が、その理論放電容
量である３７２ｍＡｈ／ｇの放電容量を持っていたとし
ても、その含有量が少なくとも９０質量％以上無けれ
ば、その放電容量は３３５ｍＡｈ／ｇに達しないため、
高放電容量の負極材料は得られないし、天然黒鉛等の鱗
片状黒鉛以外では通常達成されない３５０ｍＡｈ／ｇ以
上の高い放電容量が得るという点からは、更に望ましい
黒鉛の炭素含有量は９５質量％以上である。以上から、
本発明のリチウム二次電池負極用材料の原料として用い
る黒鉛の炭素含有量が９０質量％以上、望ましくは９５
質量％以上と規定される。炭素濃度９０質量％以上の範
囲を満足する黒鉛は、工業的に良く知られた浮遊選鉱
法、酸処理、高温熱処理等の精製プロセスを、単独ある
いは組み合わせて用いることにより容易に得られる。One of the great significance of using graphite as a negative electrode material for a lithium secondary battery is a chemical change in the charge / discharge process, that is, Li ions are inserted between graphite layers during charging to form a graphite interlayer compound. Then, the potential in the reaction in which lithium ions are desorbed at the time of discharge and returned to graphite is equal to the potential in the change of lithium metal and lithium ions, and a flat discharge curve is obtained over most of the use area. is there. Most of the charge / discharge capacity of the negative electrode material for a lithium secondary battery obtained in the present invention is obtained from graphite used as a raw material. That is, by kneading with a carbonaceous binder and then undergoing carbonization and / or graphitization,
Although the binder component is carbonized or graphitized and contributes to the discharge capacity, the high discharge capacity characteristic of the lithium secondary battery negative electrode material obtained in the present invention is obtained because of the high discharge capacity of the raw graphite itself. It is caused. Therefore, when the purity of graphite as a raw material is low, the ratio of graphite involved in the charge / discharge reaction in the negative electrode material obtained therefrom becomes small, and the negative electrode material cannot have a high discharge capacity. Even if the graphite in the negative electrode material has a discharge capacity of 372 mAh / g, which is its theoretical discharge capacity, the discharge capacity does not reach 335 mAh / g unless its content is at least 90% by mass or more. For,
From the viewpoint that a negative electrode material having a high discharge capacity cannot be obtained, and a high discharge capacity of 350 mAh / g or more, which is normally not achieved except for flaky graphite such as natural graphite, is obtained, the more desirable graphite carbon content is 95% by mass or more. It is. From the above,
The graphite used as a raw material of the negative electrode material for a lithium secondary battery of the present invention has a carbon content of 90% by mass or more, preferably 95% by mass.
% By mass or more. Graphite satisfying the carbon concentration range of 90% by mass or more can be easily obtained by using an industrially well-known purification process such as a flotation method, an acid treatment, and a high-temperature heat treatment alone or in combination.

【００１９】また、第三の要件である、原料である黒鉛
と炭素質バインダーを捏合して捏合物とした後に、熱処
理を行うことに関して説明する。そもそも本処理の最大
の意義は、原料として用いる黒鉛が有する理論容量に匹
敵する高い放電容量を維持しつつ、捏合による粒子の適
正な造粒または接着によって、不可逆容量の低減や比表
面積、タップ密度等の粉体性状の向上を図ることにあ
る。炭素質バインダーとしては、コールタールピッチ、
石油ピッチ、ナフタレンピッチ等のピッチ、３，５-ジ
メチルフエノールホルムアルデヒド樹脂、ポリ塩化ビニ
ル等の炭素を主成分としたものがあげられ、これらを溶
融したものや平均粒径５〜３００μｍに粉砕したものが
用いられる。また、この捏合とは、黒鉛粉末と炭素質バ
インダーを原料にして、緻密な黒鉛製品を製造するよう
な、従来炭素材料分野で広く用いられていた方法の応用
である。その一例を示すと、先ず、両者を混合した後、
加熱しながら撹拌、捏合する。これにより、上記黒鉛と
炭素質バインダーとの捏合物、すなわち、ビーズ状の造
粒物が得られる。この造粒物を熱処理することにより、
炭素質バインダー中の有機物が炭化または黒鉛化されリ
チウムイオンの吸脱着あるいは挿入脱離に関与すること
ができる。この熱処理を行わない場合、炭素質バインダ
ーは、熱的、化学的に安定化していないと共に、リチウ
ムイオンの吸脱着性能が極めて劣っている。加えて、熱
処理した炭素質バインダーは、前記黒鉛粉末の造粒、接
着の役割によって、副反応の低減や粉体性状の改善を可
能とするものであり、この意味でも適正な熱処理が不可
欠である。The third requirement, ie, heat treatment after kneading graphite as a raw material and a carbonaceous binder to form a kneaded product will be described. In the first place, the main significance of this treatment is that, while maintaining a high discharge capacity comparable to the theoretical capacity of graphite used as a raw material, proper granulation or adhesion of particles by kneading, reduction of irreversible capacity, specific surface area, tap density And the like to improve the powder properties. As the carbonaceous binder, coal tar pitch,
Pitches such as petroleum pitch, naphthalene pitch, etc., and those mainly composed of carbon such as 3,5-dimethylphenol formaldehyde resin, polyvinyl chloride, etc., which are melted or pulverized to an average particle size of 5 to 300 μm Is used. The kneading is an application of a method widely used in the field of carbon materials in the past, such as manufacturing a dense graphite product using graphite powder and a carbonaceous binder as raw materials. As an example, first, after mixing both,
Stir and knead while heating. As a result, a kneaded product of the graphite and the carbonaceous binder, that is, a bead-shaped granulated product is obtained. By heat-treating this granulated material,
The organic matter in the carbonaceous binder is carbonized or graphitized and can participate in the adsorption / desorption or insertion / desorption of lithium ions. When this heat treatment is not performed, the carbonaceous binder is not thermally and chemically stabilized, and has extremely poor lithium ion adsorption / desorption performance. In addition, the heat-treated carbonaceous binder enables reduction of side reactions and improvement of powder properties by the role of granulation and adhesion of the graphite powder. In this sense, proper heat treatment is indispensable. .

【００２０】また、第四の要件である、前記の捏合物を
平均粒径５μｍ以上１００μｍ未満、かつ２０回タップ
時のタップ密度を０．７０ｇ／ｃｍ3以上となるように
調製することに関して説明する。平均粒径が５μｍ未満
と小さい場合は、比表面積の増加による不可逆容量の増
加や嵩密度の低下、負極電極作製における塗工面に不均
一が発生する等の問題を生じ、また、平均粒径が１００
μｍを超えて大きい場合、リチウム二次電池負極として
電極箔に塗布した際に、必要な平滑性が得られない等の
問題が生じる。更に、充放電時での反応の均一性、粒子
内部でのＬｉイオンの拡散のしやすさから平均粒径５０
μｍ以下であることがより望ましい。この平均粒度範囲
を満足し、かつ２０回タップ時のタップ密度が０．７０
ｇ／ｃｍ 3以上となるように、捏合物の粉砕、粒度調整
を行うことにより優れたリチウム二次電池用負極材料が
得られる。このタップ密度を最適な範囲に制御すること
に関して説明する。黒鉛粉末材料のタップ密度の測定法
はＪＩＳ−Ｋ５１０１に規定されており、これに準拠し
て測定した。このタップ密度を２０回のタップ回数で規
定することについては、粉体のタップ密度はそのタップ
回数に従って上昇するが、電極製造時の安定性や操作性
は、タップ回数の少ない場合のタップ密度に強く依存す
る。また、２０回未満のタップ時のタップ密度の規定で
も同様の定義が可能だが、測定精度や測定値の再現性の
点から、タップ回数２０回の規定が最適であると考え、
ここに規定した。リチウム二次電池負極用材料としての
黒鉛において、タップ密度を向上させることは、電極箔
塗工工程の安定操業を容易にするのみならず、材料の運
送、保管等の操作においても重要である。例えば、類似
の粒度分布を持つ天然黒鉛と、メソフェーズ小球体を比
較すると、天然黒鉛のタップ密度は１／３〜１／５と低
く、これがために塗工液作製時に同質量の黒鉛を用いた
場合に、その液粘度は極めて大きくなり、均一な塗工が
より困難になる等の問題を生じる。この平均粒径とタッ
プ密度の制御を行うことは、捏合物の原料として用いる
黒鉛の平均粒径及び粒度分布を適性に制御すること、及
び／または、得られた捏合物を、冷却後に、所定の粒度
になるまで粉砕及び必要に応じて分級することにより達
成される。原料黒鉛の平均粒度は、目的とする最終生成
物の平均粒度以下とすることが好ましいし、捏合物を粉
砕、分級した際の粒径は、出発原料となる黒鉛の粒径よ
り大きくするのが好ましい。生成物であるリチウム二次
電池負極用材料の平均粒径を出発原料の粒径より小さく
すると、出発原料である黒鉛粒子の破壊が起こり、性能
上望ましくない。即ち、本発明のリチウム二次電池負極
用材料において、平均粒径５μｍ以上１００μｍ未満、
かつ２０回タップ時のタップ密度が０．７０ｇ／ｃｍ3
以上を満足すれば、天然黒鉛で見られた塗工液作製の際
の困難を回避できることがわかった。Further, the above-mentioned kneaded material which is the fourth requirement is
Average particle size 5μm or more and less than 100μm, and tap 20 times
Tap density at the time of 0.70g / cmThreeTo be more than
The preparation will be described. Average particle size is less than 5μm
, The irreversible capacity increases due to the increase in specific surface area.
Addition, decrease in bulk density, uneven surface
And the average particle size is 100%.
When it is larger than μm, it can be used as a negative electrode for lithium secondary batteries.
When applied to electrode foil, required smoothness cannot be obtained.
Problems arise. Furthermore, the uniformity of the reaction during charging and discharging,
The average particle size is 50 due to the ease of diffusion of Li ions inside.
More preferably, it is not more than μm. This average particle size range
And the tap density at the time of 20 taps is 0.70
g / cm ThreeAs mentioned above, grinding and kneading of the kneaded material
By doing, excellent negative electrode materials for lithium secondary batteries can be
can get. To control this tap density to the optimal range
Will be described. Method for measuring tap density of graphite powder materials
Is defined in JIS-K5101, and conforms to this.
Measured. This tap density is defined by 20 taps.
The tap density of the powder is
It increases with the number of times, but stability and operability during electrode production
Strongly depends on the tap density when the number of taps is small.
You. Also, the tap density for taps less than 20 times
Can be defined in the same way, but the measurement accuracy and reproducibility
From the point of view, we consider that the rule of 20 taps is optimal,
Specified here. As material for negative electrode of lithium secondary battery
Improving tap density in graphite requires electrode foil
In addition to facilitating stable operation of the coating process,
It is also important in operations such as sending and storing. For example, similar
Of natural graphite with a particle size distribution of
By comparison, the tap density of natural graphite is as low as 1/3 to 1/5.
Therefore, the same mass of graphite was used when preparing the coating liquid.
In such a case, the liquid viscosity becomes extremely large, and a uniform coating is obtained.
Problems such as becoming more difficult occur. This average particle size and
To control the press density, use as a raw material of the kneaded material
Properly controlling the average particle size and particle size distribution of graphite; and
And / or after cooling the obtained kneaded product,
By grinding and classifying as necessary
Is done. The average particle size of raw graphite is
It is preferred that the average particle size of the
The particle size when crushed and classified is the same as the particle size of the starting material graphite.
It is preferable to make it larger. Lithium secondary product
The average particle size of the battery anode material is smaller than that of the starting material.
Then, the starting graphite particles are destroyed,
Not desirable. That is, the negative electrode of the lithium secondary battery of the present invention
In the material for use, the average particle size is 5 μm or more and less than 100 μm,
And the tap density at the time of 20 taps is 0.70 g / cm.Three
If the above conditions are satisfied, the production of the coating liquid seen with natural graphite
It was found that the difficulties could be avoided.

【００２１】以上のように、上記要件（１）、即ち前記
第一から第四までのすべての要件を同時に満たすことに
より、リチウム二次電池負極用炭素材料として、天然黒
鉛等の鱗片状黒鉛の最高水準の放電容量もしくは黒鉛構
造から決定される理論容量と同程度の放電容量を持つと
共に、かつ充電初期における副反応に起因する不可逆容
量が小さく、大きな充放電電流下で使用した場合に高い
放電容量が得られる等の優れた特性が得られ、鱗片状黒
鉛の問題を解決したリチウム二次電池負極用材料が提供
されるに至った。As described above, by simultaneously satisfying the requirement (1), that is, all of the first to fourth requirements, a carbon material for a negative electrode of a lithium secondary battery can be obtained by using scaly graphite such as natural graphite. It has the highest level of discharge capacity or the same discharge capacity as the theoretical capacity determined from the graphite structure, and has a small irreversible capacity due to side reactions in the initial stage of charging, and a high discharge when used under a large charge / discharge current Excellent characteristics such as high capacity have been obtained, and a negative electrode material for a lithium secondary battery has been provided which has solved the problem of flaky graphite.

【００２２】更に、本発明のリチウム二次電池負極用材
料の要件として、上記要件（１）に加えて、前記捏合物
の炭素質バインダーが熱処理により炭化物になっていて
も良い。これを以下の記述にて上記要件（２）と呼ぶ。Further, as a requirement of the material for a negative electrode of a lithium secondary battery of the present invention, in addition to the requirement (1), the carbonaceous binder of the kneaded product may be turned into a carbide by heat treatment. This is referred to as requirement (2) in the following description.

【００２３】前記捏合物を熱処理して捏合物を炭化する
ためには、非酸化性雰囲気下で７００℃以上１５００℃
以下の温度で熱処理することが望ましい。７００℃以上
１５００℃以下での熱処理は、捏合物中の炭素質バイン
ダーに含まれる揮発成分を飛散させ、かつ炭素質バイン
ダーを炭化させるものである。その温度は、炭素質バイ
ンダーの種類に併せて、上記温度範囲内で適切な温度を
設定すれば良い。この加熱温度が７００℃より低いと、
炭素質バインダーを充分に炭化しにくい。また、１５０
０℃より高くても良いが、１５００℃程度あれば、バイ
ンダーの揮発成分はほぼ飛散し、炭化の目的をほぼ達成
することができるので、１５００℃程度で充分である。
即ち、上記要件（１）に加えて、熱処理によって捏合物
の炭素質バインダーを炭化物とした本発明の材料は、リ
チウム二次電池負極用炭素材料として優れた特性を示
す。In order to carbonize the kneaded material by heat-treating the kneaded material, the temperature is 700 ° C. or more and 1500 ° C. in a non-oxidizing atmosphere.
It is desirable to perform the heat treatment at the following temperature. The heat treatment at 700 ° C. or more and 1500 ° C. or less disperses volatile components contained in the carbonaceous binder in the kneaded material and carbonizes the carbonaceous binder. The temperature may be set to an appropriate temperature within the above temperature range according to the type of the carbonaceous binder. If this heating temperature is lower than 700 ° C.,
It is difficult to sufficiently carbonize the carbonaceous binder. Also, 150
The temperature may be higher than 0 ° C., but if it is about 1500 ° C., the volatile component of the binder is almost scattered, and the purpose of carbonization can be almost achieved, so that about 1500 ° C. is sufficient.
That is, in addition to the above requirement (1), the material of the present invention in which the carbonaceous binder of the kneaded material is made into a carbide by heat treatment exhibits excellent characteristics as a carbon material for a negative electrode of a lithium secondary battery.

【００２４】また、本発明のリチウム二次電池負極用材
料の要件として、上記要件（１）に加えて、前記炭素材
料が、黒鉛化物であることが好ましい。これを以下の記
述にて上記要件（３）と呼ぶ。この黒鉛化物は、前記捏
合物を必要に応じて炭化処理を行った後、２４００℃以
上３０００℃以下で黒鉛化することにより得られる。黒
鉛化に先立つ炭化処理は、通常、７００℃以上１５００
℃以下程度の温度で行い、黒鉛化処理での操業安定性、
安全性の点で行うことが望ましいが、これらの問題が回
避可能であれば、目的の材料を得るために炭化処理は省
略可能である。即ち、黒鉛化処理によって、本発明の効
果が更に顕著に得られる。即ち、この温度領域での熱処
理により、黒鉛の純化と炭素質バインダーの黒鉛化が同
時に進行し、これらにより放電容量の更なる増加が得ら
れる。この黒鉛化温度が２４００℃未満では、炭素質バ
インダーの黒鉛化が充分に進まず、処理の効果である放
電容量の増加は充分に得られない。また、３０００℃よ
り高くても良いが、安全性や経済性から３０００℃以下
で充分である。即ち、上記要件（１）に加えて、前記炭
素材料を黒鉛化物とすることにより得られる材料は、リ
チウム二次電池負極用材料として優れた特性を示す。Further, as a requirement of the negative electrode material for a lithium secondary battery of the present invention, in addition to the requirement (1), it is preferable that the carbon material is a graphitized material. This is referred to as requirement (3) in the following description. This graphitized product can be obtained by subjecting the kneaded product to a carbonization treatment as necessary, and then graphitizing it at 2400 ° C. or more and 3000 ° C. or less. The carbonization treatment prior to graphitization is usually performed at 700 ° C. or more and 1500 ° C.
Temperature at about ℃ or lower, the operation stability in the graphitization process,
Although it is desirable to carry out the method from the viewpoint of safety, if these problems can be avoided, the carbonization treatment can be omitted to obtain a desired material. That is, the effect of the present invention can be more remarkably obtained by the graphitization treatment. That is, by the heat treatment in this temperature range, the purification of the graphite and the graphitization of the carbonaceous binder proceed simultaneously, thereby further increasing the discharge capacity. If the graphitization temperature is less than 2400 ° C., the graphitization of the carbonaceous binder does not proceed sufficiently, and the increase in discharge capacity, which is an effect of the treatment, cannot be sufficiently obtained. Although it may be higher than 3000 ° C., 3000 ° C. or lower is sufficient from the viewpoint of safety and economy. That is, in addition to the requirement (1), a material obtained by converting the carbon material into a graphitic material exhibits excellent characteristics as a material for a negative electrode of a lithium secondary battery.

【００２５】さらに、本発明のリチウム二次電池負極用
材料の要件として、上記要件（１）〜（３）に加えて、
３００回タップ時のタップ密度が０．８５ｇ／ｃｍ3以
上であることが好ましい。これを以下の記述にて上記要
件（４）と呼ぶ。即ち、上記要件（４）は、上記要件
（１）で規定した２０回タップ時のタップ密度が０．７
０ｇ／ｃｍ3以上という要件に加えて、３００回タップ
時のタップ密度０．８５ｇ／ｃｍ3を満足することによ
り、粉体としての特性がさらに改善されるというもので
ある。本発明の上記要件（１）の規定の説明において、
電極製造時の安定性や操作性はタップ回数の少ない場合
のタップ密度（本発明で２０回タップ時を規定）に強く
依存することを述べたが、ここで更に、３００回タップ
時のタップ密度を規定することにより、平均粒度が一定
範囲、かつタップ回数が少ない場合の適正なタップ密度
を満足した上で、タップ回数が多い場合のタップ密度を
一定以上に成さしめることで、更に顕著に本発明の効果
を得ることを見出したものである。例えば、２０回タッ
プ時のタップ密度が０．７０ｇ／ｃｍ3以上で同等であ
る２種類の粉体Ａ、Ｂにおいて、粉体Ａの３００回タッ
プ時のタップ密度が０．８５ｇ／ｃｍ3未満、粉体Ｂの
それが０．８５ｇ／ｃｍ3以上であるとすると、電極箔
塗工工程での溶媒を用いたスラリー作製時や、塗工後の
電極箔プレスの際の操作性において、粉体Ｂの方が操作
性が容易かつ製造した電極箔の安定性は優れている。こ
れは、スラリー作製時の混練工程や塗工後のプレス工程
においては、一定以上の嵩密度を出発状態として、さら
に高い嵩密度への変化が起こることから、その変化の容
易さが３００回タップ時のタップ密度で表現されるもの
と考えられる。即ち、３００回タップ密度が０．８５ｇ
／ｃｍ3以上であれば、本発明の効果がさらに顕著に示
されることが分かった。Further, in addition to the above requirements (1) to (3), the requirements for the negative electrode material for a lithium secondary battery of the present invention are as follows:
The tap density at the time of tapping 300 times is preferably 0.85 g / cm 3 or more. This is referred to as requirement (4) in the following description. That is, the requirement (4) is such that the tap density at the time of 20 taps specified in the requirement (1) is 0.7.
By satisfying the tap density of 0.85 g / cm 3 at 300 taps in addition to the requirement of 0 g / cm 3 or more, the properties as a powder are further improved. In the description of the requirement (1) of the present invention,
It was stated that the stability and operability at the time of manufacturing the electrode strongly depend on the tap density when the number of taps is small (the present invention defines 20 taps). By defining the average particle size in a certain range, and satisfying the appropriate tap density in the case of a small number of taps, by making the tap density in the case of a large number of taps more than a certain, more remarkably It has been found that the effects of the present invention can be obtained. For example, in two types of powders A and B having the same tap density of 0.70 g / cm 3 or more at 20 taps, the tap density of powder A at 300 taps is less than 0.85 g / cm 3. Assuming that that of the powder B is 0.85 g / cm 3 or more, the powder operability at the time of preparing a slurry using a solvent in the electrode foil coating step or pressing the electrode foil after coating is low. The body B is easier to operate and has better stability of the manufactured electrode foil. This is because, in the kneading step at the time of preparing the slurry or the pressing step after coating, a change to a higher bulk density occurs starting from a certain bulk density, and the ease of the change is 300 taps. It is considered that it is expressed by the tap density at the time. That is, the tap density of 300 times is 0.85 g.
/ Cm 3 or more, the effect of the present invention was found to be more remarkable.

【００２６】さらに、本発明のリチウム二次電池負極用
材料の要件として、上記要件（１）〜（４）に加えて、
炭素含有量が９９質量％以上、かつＢＥＴ法による比表
面積が５ｍ2／ｇ以下であるものが好ましい。即ち、上
記要件（１）〜（４）に加えて、炭素含有量を一定の割
合以上に高めること、比表面積を一定の値以下に制御す
ることのすべてを満たすものである。これを以下の記述
にて、上記要件（５）と呼ぶ。本要件を構成する因子で
ある、リチウム二次電池負極用材料の炭素含有量に関し
て説明する。この炭素含有量が高いほど、リチウムイオ
ンの挿入、脱離に関与する黒鉛構造の割合が大きいた
め、負極材料として得られる放電容量が大きくなるが、
これに加えて、鉄等の金属元素や吸着水分等、炭素以外
の元素、化合物の含有量を少なくすることが重要であ
る。炭素含有量が９９質量％未満の場合、不純物金属の
影響により、電解液等の劣化によるサイクル特性の低下
や不可逆容量の増加が、また、水分の影響により、非水
電解液の劣化や塗工行程での塗工液の安定性低下等の問
題が生じる。これらの悪影響を低減するために、炭素含
有量を９９質量％以上、好ましくは９９．５質量％以上
とする。Further, in addition to the above requirements (1) to (4), the requirements for the negative electrode material for a lithium secondary battery of the present invention are as follows:
Those having a carbon content of 99% by mass or more and a specific surface area by a BET method of 5 m 2 / g or less are preferable. That is, in addition to the above requirements (1) to (4), all of increasing the carbon content to a certain ratio or more and controlling the specific surface area to a certain value or less are satisfied. This is referred to as requirement (5) in the following description. The carbon content of the material for the negative electrode of a lithium secondary battery, which is a factor constituting this requirement, will be described. The higher the carbon content, the greater the proportion of the graphite structure involved in lithium ion insertion and desorption, so that the discharge capacity obtained as a negative electrode material increases,
In addition, it is important to reduce the content of elements and compounds other than carbon, such as metal elements such as iron and adsorbed moisture. When the carbon content is less than 99% by mass, the deterioration of the electrolytic solution and the like causes the deterioration of the cycle characteristics and the increase of the irreversible capacity due to the influence of the impurity metal. Problems such as a decrease in the stability of the coating solution during the process occur. In order to reduce these adverse effects, the carbon content is set to 99% by mass or more, preferably 99.5% by mass or more.

【００２７】また、同じくＢＥＴ比表面積に関して説明
する。ＢＥＴ比表面積は、黒鉛粉末の比表面積を記述す
る一般的な指標として、当業界を始め炭素、黒鉛に関連
する技術分野で広く用いられている。これは、予め吸着
物を脱離させて、真空容器に入れた粉末に、液体窒素温
度にて窒素ガスを吸着させて、その等温吸着曲線を求め
ることにより得られる。このＢＥＴ法による比表面積が
５ｍ2／ｇ超とした場合、負極電極作製の際に塗工面に
むらや不均一部分が発生する、あるいは大気中水分の吸
着が顕著となり不純物濃度が増加する、あるいは充放電
初期の副反応が増大する等、電極性能の劣化が顕著とな
る。The BET specific surface area will also be described. The BET specific surface area is widely used as a general index for describing the specific surface area of graphite powder in the technical field related to carbon and graphite, including the industry. This is obtained by desorbing the adsorbed material in advance, adsorbing nitrogen gas at a liquid nitrogen temperature to powder placed in a vacuum vessel, and obtaining an isothermal adsorption curve thereof. When the specific surface area by this BET method is more than 5 m 2 / g, unevenness or uneven portion is generated on the coated surface at the time of producing the negative electrode, or the adsorption of atmospheric moisture is remarkable, and the impurity concentration increases, or Deterioration of electrode performance becomes remarkable, such as an increase in side reactions at the beginning of charging and discharging.

【００２８】以上の要件を満たすことにより、リチウム
二次電池負極用炭素材料として、天然黒鉛等の鱗片状黒
鉛の最高水準の放電容量もしくは黒鉛構造から決定され
る理論容量と同程度の放電容量を持つと共に、かつ充電
初期における副反応に起因する不可逆容量が小さく、大
きな充放電電流下で使用した場合に高い放電容量が得ら
れる等の優れた特性が得られ、鱗片状黒鉛の問題を解決
したリチウム二次電池用負極材料が提供されることを示
された。By satisfying the above requirements, as a carbon material for a negative electrode of a lithium secondary battery, the highest discharge capacity of flaky graphite such as natural graphite or the same as the theoretical capacity determined from the graphite structure is obtained. It has excellent characteristics such as having a small irreversible capacity due to side reactions in the early stage of charging, and a high discharge capacity when used under a large charge / discharge current, and solved the problem of flaky graphite. It has been shown that a negative electrode material for a lithium secondary battery is provided.

【００２９】次に、上記本発明のリチウム二次電池負極
用黒鉛の製造方法について説明する。Next, a method for producing the graphite for a negative electrode of a lithium secondary battery of the present invention will be described.

【００３０】本発明の製造方法は、金属と炭素の溶融状
態の冷却過程に析出した炭素の処理が、炭素含有量が９
０質量％以上に達するまで高純度化処理を行った後に、
インペラーミル、ジェットミル、レイモンドミルまたは
ボールミルより選ばれた粉砕機を用いた粉砕と空気分級
を行い、得られた黒鉛を、炭素質バインダーと捏合し、
該捏合物を７００〜１５００℃で炭化及び／または２４
００〜３０００℃で黒鉛化することを特徴とする、リチ
ウム二次電池負極用材料の製造方法である。本要件を以
下の記述で、上記要件（６）と呼ぶ。即ち、上記要件
（６）は、優れたリチウム二次電池負極用材料を容易に
かつ工業的に製造する目的で、先ず原料黒鉛を得る際
に、金属と炭素の溶融状態の冷却過程に析出した炭素の
高純度化処理を行い、一定以上の炭素含有量とした後
に、最適な粉砕機を用いた粉砕と空気分級で粒度調整を
行い、これを原料としてバインダーとの捏合物を得た
後、最適な熱処理をすることを特徴とする製造方法であ
る。本発明の製造方法により、優れた特性を持つリチウ
ム二次電池負極用材料を、より容易にかつ高い工程歩留
で得ることが可能である。ここで言う高純度化とは、金
属と炭素の溶融状態の冷却過程に析出した炭素の炭素含
有量を９０質量％以上に高めるための処理であり、浮遊
選鉱法、酸処理、高温熱処理等の一般に知られた精製プ
ロセスを単独あるいは組み合わせて用いることである。
高純度化処理を行う前に粉砕、分級といった粒度調製を
行った場合は、高純度化処理で大部分の金属粒子が脱離
すること等に起因する粒度変化により、原料である黒鉛
の平均粒度を制御することが困難である。また、高純度
化の後に粉砕を行わなければ、所定の平均粒度を持つ製
品を高い歩留で得ることはできない。また、インペラー
ミル、ジェットミル、レイモンドミル、ボールミルより
選ばれる粉砕機を用いることにより、粉砕を経ていない
黒鉛を用いる場合に比べて、生成したリチウム二次電池
負極用材料の嵩密度、タップ密度等の粉体特性値の向上
が容易になし得る。これは、原料を粉砕する効果とし
て、高純度化処理直後に存在する鱗片状粒子の形状が、
粉砕工程中に角がとれて、より球状に近く変化し、これ
が炭素質バインダーとの捏合やその後の炭化、黒鉛化と
いった処理を経て製造されるリチウム二次電池負極用材
料の物性にも反映されることによる。この粉砕工程にお
いて、鱗片状粒子の大部分の形状を変化させ、曲面形状
粒子にならしめることが、上記要件（６）の根幹をなす
ものである。粉砕現象そのものは、粒子が割れたり、欠
けたりするものであるが、粉砕機内部において、粒子同
士が接触、衝突、摩耗を繰り返すことにより、燐片状黒
鉛粒子が曲面形状粒子に変化して、リチウム二次電池負
極用材料の原料黒鉛としての高い適性が得られると推定
される。この黒鉛を炭素質バインダーと捏合して、捏合
物を得た後、該捏合物を７００℃以上１５００℃以下で
炭化及び／または２４００℃以上３０００℃以下で黒鉛
化することにより、目的とするリチウム二次電池負極用
材料が得られる。７００℃以上１５００℃以下での熱処
理は、捏合物中の炭素質バインダーに含まれる揮発成分
を飛散させ、かつ炭素質バインダーを炭化させるもので
ある。その温度は、炭素質バインダーの種類に併せて、
上記温度範囲内で適切な温度を設定すれば良い。この加
熱温度が７００℃より低いと、炭素質バインダーを充分
に炭化しにくい。また、１５００℃より高くても良い
が、１５００℃程度あれば、炭素質バインダーの揮発成
分はほぼ飛散するので、炭化の目的をほぼ達成すること
ができる１５００℃程度で充分である。この炭化処理後
に得られる粉末を必要に応じた粒度調製を行って、リチ
ウム二次電池負極用炭素材料として用いることができる
が、更に、前記の炭化に続いて、或いは炭化に代えて２
４００℃以上３０００℃以下の温度で黒鉛化処理するこ
とにより、本発明の効果は更に顕著に得られる。即ち、
この温度領域での熱処理により、黒鉛の純化と炭素質バ
インダーの黒鉛化が同時に進行し、これらにより放電容
量の更なる増加が得られる。この黒鉛化温度が２４００
℃未満では、炭素質バインダーの黒鉛化が充分に進ま
ず、処理の効果である放電容量の増加は充分に得られな
い。また、３０００℃より高くても良いが、安全性や経
済性から３０００℃以下で充分である。According to the production method of the present invention, the treatment of carbon deposited during the cooling process of the molten state of metal and carbon is carried out when the carbon content is 9%.
After performing the purification treatment until it reaches 0% by mass or more,
Impeller mill, jet mill, pulverization and air classification using a pulverizer selected from Raymond mill or ball mill, kneaded graphite obtained, carbonaceous binder,
The kneaded material is carbonized at 700 to 1500 ° C. and / or 24
A method for producing a material for a negative electrode of a lithium secondary battery, comprising graphitizing at 00 to 3000 ° C. This requirement is referred to as requirement (6) in the following description. That is, the requirement (6) is that, in order to easily and industrially produce an excellent material for a negative electrode of a lithium secondary battery, when a raw material graphite is first obtained, it is deposited in a cooling process in a molten state of metal and carbon. After performing a high-purity treatment of carbon, and a carbon content of a certain level or more, after performing particle size adjustment by pulverization and air classification using an optimal pulverizer, after obtaining a kneaded product with a binder as a raw material, This is a manufacturing method characterized by performing optimal heat treatment. According to the production method of the present invention, a material for a negative electrode of a lithium secondary battery having excellent characteristics can be obtained more easily and with a higher process yield. The term "high purification" as used herein refers to a treatment for increasing the carbon content of carbon precipitated during the cooling process of the molten state of metal and carbon to 90% by mass or more, such as flotation, acid treatment, and high-temperature heat treatment. A commonly used purification process is used alone or in combination.
If particle size adjustment such as pulverization and classification is performed before high-purification treatment, the average particle size of the raw material graphite is changed due to the change in particle size caused by the desorption of most metal particles during the high-purification treatment. Is difficult to control. Further, unless pulverization is performed after purification, a product having a predetermined average particle size cannot be obtained at a high yield. In addition, by using a pulverizer selected from an impeller mill, a jet mill, a Raymond mill, and a ball mill, the bulk density, tap density, etc. of the produced lithium secondary battery negative electrode material can be reduced as compared with the case of using graphite that has not been pulverized. Can be easily improved. This is as an effect of pulverizing the raw material, the shape of the flaky particles that exist immediately after the high-purification treatment,
During the pulverization process, the corners are removed and change to a more spherical shape, which is also reflected in the physical properties of the lithium secondary battery negative electrode material manufactured through processes such as kneading with a carbonaceous binder and subsequent carbonization and graphitization. It depends. In the pulverization step, changing the shape of most of the flake-shaped particles to make them into curved particles is the basis of the requirement (6). The crushing phenomenon itself is that the particles are cracked or chipped, but inside the crusher, the particles are repeatedly contacted, collided and abraded, and the flake graphite particles are changed into curved particles, It is estimated that high suitability as a raw material graphite for a negative electrode material of a lithium secondary battery is obtained. This graphite is kneaded with a carbonaceous binder to obtain a kneaded material, and the kneaded material is carbonized at 700 ° C to 1500 ° C and / or graphitized at 2400 ° C to 3000 ° C to obtain the desired lithium. A material for a secondary battery negative electrode is obtained. The heat treatment at 700 ° C. or more and 1500 ° C. or less disperses volatile components contained in the carbonaceous binder in the kneaded material and carbonizes the carbonaceous binder. The temperature depends on the type of carbonaceous binder,
An appropriate temperature may be set within the above temperature range. If the heating temperature is lower than 700 ° C., it is difficult to sufficiently carbonize the carbonaceous binder. The temperature may be higher than 1500 ° C., but if it is about 1500 ° C., the volatile component of the carbonaceous binder is almost scattered, so that about 1500 ° C. which can substantially achieve the purpose of carbonization is sufficient. The powder obtained after this carbonization treatment can be used as a carbon material for a negative electrode of a lithium secondary battery by adjusting the particle size as required, and further, following the carbonization or instead of carbonization,
By performing the graphitization treatment at a temperature of 400 ° C. or more and 3000 ° C. or less, the effect of the present invention can be more remarkably obtained. That is,
By the heat treatment in this temperature range, the purification of the graphite and the graphitization of the carbonaceous binder simultaneously proceed, thereby further increasing the discharge capacity. This graphitization temperature is 2400
If the temperature is lower than ℃, the graphitization of the carbonaceous binder does not sufficiently proceed, and the increase in discharge capacity, which is an effect of the treatment, cannot be sufficiently obtained. Although it may be higher than 3000 ° C., 3000 ° C. or lower is sufficient from the viewpoint of safety and economy.

【００３１】また、本発明では、上記要件（６）に加え
て、前記金属が、鉄、ニッケル、シリコン、コバルトよ
り選ばれた１種または２種以上の金属であるリチウム二
次電池負極用黒鉛の製造方法であることが好ましい。Further, in the present invention, in addition to the above requirement (6), graphite for a negative electrode of a lithium secondary battery, wherein the metal is one or more metals selected from iron, nickel, silicon, and cobalt. Is preferred.

【００３２】炭素は、高温において多くの金属と溶融状
態をとる。一般に、これを冷却すると、炭素の溶解限界
濃度が減少することから、黒鉛として析出する。その析
出の温度や量は、用いる金属種により大きく異なり、例
えば、ニッケルは２０００℃において、約２０原子％の
炭素を含む溶融状態を取り得、これを１５００℃まで冷
却した際に前記２０原子％の内、約７原子％に相当する
炭素が黒鉛として析出する。金属種によっては、高温に
おいて液体状態になっても、炭素をほとんど溶解しない
ものや、また、溶解しても黒鉛として析出しないものが
あり、これらは本発明の金属として用いるに適さない。
即ち、少なくとも鉄、ニッケル、シリコン、コバルトと
炭素を、所定量混合した試料を不活性雰囲気下で高温加
熱し、冷却することにより得られる黒鉛を処理して、上
記要件（３）を満たす製造を行うことにより得られる材
料は、リチウム二次電池負極として優れた特性を有す
る。Carbon is in a molten state with many metals at high temperatures. Generally, when this is cooled, the solubility limit concentration of carbon decreases, so that it precipitates as graphite. The temperature and amount of the precipitation vary greatly depending on the type of metal used. For example, nickel can take a molten state containing about 20 atomic% of carbon at 2000 ° C., and when this is cooled to 1500 ° C., the above 20 atomic% Among them, about 7 atomic% of carbon is precipitated as graphite. Some metal species hardly dissolve carbon even when they are in a liquid state at high temperature, and others do not precipitate as graphite when dissolved, and these are not suitable for use as the metal of the present invention.
That is, a sample in which at least iron, nickel, silicon, cobalt and carbon are mixed in a predetermined amount is heated at a high temperature in an inert atmosphere, and the graphite obtained by cooling is treated to produce a product satisfying the above requirement (3). The material obtained by performing the method has excellent characteristics as a negative electrode for a lithium secondary battery.

【００３３】また、本発明は、上記要件（６）に加え
て、前記金属と炭素の溶融状態が、製鉄プロセスの溶融
銑鉄における鉄と炭素の溶融状態であることを特徴とす
るリチウム二次電池負極用黒鉛の製造方法であっても良
い。鉄は、２５００℃において、約２５原子％の炭素を
含む溶融状態を取り得、これを冷却した場合に、その溶
融限界量は低下し、これを超えた炭素が黒鉛として析出
する。製鉄プロセスにおいては、製銑工程にて炭素を含
んだ高温溶融反応物が得られ、その反応物の運搬及び精
製等の工程にて、反応物温度が下がり炭素が析出し、そ
の多くが製銑ダスト及び製鋼ダストとして回収されてい
る。該ダスト中の炭素濃度は、回収段階で４０〜６０質
量％程度である。上記要件（２）のリチウム二次電池負
極用黒鉛の製造方法において、原料として該ダストを用
いることが、その生成原理から見て可能である。また、
現実の工業プロセスから大量に産出する原料を得ること
ができ、該プロセスで原料を得ることが、その物性安定
化や経済性の点で優れた方法である。即ち、該ダストを
処理して上記要件（３）を満たす製造を行うことにより
得られる材料は、リチウム二次電池負極として優れた特
性を有する。[0033] In addition to the above requirement (6), the present invention provides the lithium secondary battery, wherein the molten state of the metal and carbon is a molten state of iron and carbon in molten pig iron in an iron making process. A method for producing graphite for a negative electrode may be used. Iron can assume a molten state containing about 25 atomic% of carbon at 2500 ° C., and when cooled, its melting limit is reduced, and carbon beyond this is deposited as graphite. In the iron making process, a high-temperature molten reactant containing carbon is obtained in the iron making process, and the temperature of the reactant drops in the process of transporting and refining the reactant, and carbon is precipitated, and most of the iron is produced. Collected as dust and steelmaking dust. The carbon concentration in the dust is about 40 to 60% by mass at the recovery stage. In the method for producing graphite for a negative electrode of a lithium secondary battery according to the requirement (2), it is possible to use the dust as a raw material in view of the generation principle. Also,
Raw materials produced in large quantities from an actual industrial process can be obtained, and obtaining the raw materials by the process is an excellent method in terms of stabilization of physical properties and economic efficiency. That is, a material obtained by treating the dust to satisfy the requirement (3) has excellent characteristics as a negative electrode for a lithium secondary battery.

【００３４】また、本発明は、上記要件（６）に加え
て、前記黒鉛の平均粒径が３μｍ以上３０μｍ以下であ
ることを特徴とするリチウム二次電池負極用材料の製造
方法であることが好ましい。これは、本発明の捏合処理
が、粒子の造粒を行うことから、その処理前の原料粒径
により、最終的に生成する材料の粒径も大きな影響を受
ける。リチウム二次電池負極用材料としての望ましい平
均粒径は、５μｍ以上１００μｍ未満、望ましくは５〜
５０μｍの範囲である。この範囲外では、負極材料とし
ての性能、使用性の点で劣る。原料黒鉛の平均粒径が３
μｍ以上３０μｍ以下とすることにより、適正な捏合の
条件にて、望ましい粒度範囲の製品が得られることがわ
かった。Further, the present invention, in addition to the above requirement (6), is a method for producing a negative electrode material for a lithium secondary battery, characterized in that the graphite has an average particle size of 3 μm or more and 30 μm or less. preferable. This is because the kneading process of the present invention granulates particles, and the particle size of the material finally produced is greatly affected by the raw material particle size before the processing. Desirable average particle size as a material for a negative electrode of a lithium secondary battery is 5 μm or more and less than 100 μm, preferably 5 to
The range is 50 μm. Outside this range, performance and usability as a negative electrode material are inferior. The average particle size of raw graphite is 3
It was found that a product having a desirable particle size range can be obtained under appropriate kneading conditions by setting the thickness to be from 30 μm to 30 μm.

【００３５】さらに、本発明は、上記要件（６）に加え
て、前記捏合物が、前記黒鉛と前記炭素質バインダーを
捏合し、前記炭素質バインダーの軟化点以上の温度に加
熱しながら、撹拌、捏合したものであるリチウム二次電
池負極用材料の製造方法であることが好ましい。黒鉛と
炭素質バインダーを混合、撹拌しながら、加熱を行うこ
とにより、本発明の捏合が進行し得るが、この際の加熱
温度は、炭素質バインダーの軟化点以上でないと、捏合
及び黒鉛の粒子の造粒はほとんど進行しないため、良好
なリチウム二次電池負極用材料は得られない。Further, in the present invention, in addition to the above requirement (6), the kneaded product is obtained by kneading the graphite and the carbonaceous binder, and stirring the mixture while heating to a temperature equal to or higher than the softening point of the carbonaceous binder. It is preferable to use a method for producing a material for a negative electrode of a lithium secondary battery, which is obtained by kneading. The kneading of the present invention can proceed by heating while mixing and stirring the graphite and the carbonaceous binder.However, if the heating temperature at this time is not higher than the softening point of the carbonaceous binder, the kneading and graphite particles are performed. Does not substantially proceed, so that a good lithium secondary battery negative electrode material cannot be obtained.

【００３６】また、本発明は、上記要件（６）に加え
て、前記黒鉛と前記炭素質バインダーの捏合割合が、黒
鉛１００質量部に対して、炭素質バインダーが１０〜７
０質量部であるリチウム二次電池負極用材料の製造方法
であることが好ましい。この黒鉛と炭素質バインダーの
捏合割合が、１０質量部未満では、天然黒鉛同士の接着
性能が低下するので好ましくなく、また、７０質量部を
超えると、得られる捏合物中の炭素質バインダーの製品
における寄与率が大きくなり、放電容量の低下が誘引さ
れるため好ましくない。Further, in the present invention, in addition to the above requirement (6), the kneading ratio of the graphite and the carbonaceous binder is such that the carbonaceous binder is 10 to 7 parts by mass with respect to 100 parts by mass of the graphite.
Preferably, the method is a method for producing a negative electrode material for a lithium secondary battery, which is 0 parts by mass. When the kneading ratio of the graphite and the carbonaceous binder is less than 10 parts by mass, the adhesion performance between natural graphites is unfavorably reduced, and when it exceeds 70 parts by mass, the product of the carbonaceous binder in the obtained kneaded product is not preferable. Is unfavorable because the contribution ratio becomes large and the discharge capacity is reduced.

【００３７】さらに、本発明は、正極活物質、負極活物
質及び非水系電解質を含有するリチウム二次電池におい
て、上記要件（１）〜（５）の、少なくとも何れかを満
たす材料を負極活物質に含んでなることを特徴とするリ
チウム二次電池である。上記要件（１）〜（５）の材料
は、リチウム二次電池負極として優れた特性を持ち、こ
れを負極活物資として用いて、リチウム二次電池を製造
した場合、負極活物質が、従来材料の負極活物質に比べ
て、高容量等優れた性質を有するため、より高性能のリ
チウム二次電池が得られる。また、必要に応じて他の負
極活物質と混合しても、本発明の効果である高い放電容
量等の効果が得られる。Further, according to the present invention, in a lithium secondary battery containing a positive electrode active material, a negative electrode active material and a non-aqueous electrolyte, a material satisfying at least one of the above requirements (1) to (5) is used. And a lithium secondary battery. The materials of the above requirements (1) to (5) have excellent characteristics as a negative electrode for a lithium secondary battery, and when a lithium secondary battery is manufactured by using this as a negative electrode active material, the negative electrode active material is a conventional material. As compared with the negative electrode active material described above, it has excellent properties such as high capacity, so that a higher performance lithium secondary battery can be obtained. In addition, the effect of the present invention, such as a high discharge capacity, can be obtained by mixing with another negative electrode active material as needed.

【００３８】本発明のリチウム二次電池負極用材料を活
物質に用いて負極を形成する方法としては、本発明のリ
チウム二次電池負極用材料の性能を充分に引き出し且
つ、賦形性が高く、化学的、電気化学的に安定であれ
ば、何らこれを制限するものではない。例示すると、本
発明のリチウム二次電池負極用材料に、ポリテトラフル
オロエチレン等フッ素系樹脂の粉末あるいはディスパー
ジョン溶液を添加後、混合、混練する方法がある。ま
た、本発明のリチウム二次電池負極用材料にポリフッ化
ビニリデン（ＰＶｄＦ）等のフッ素系樹脂粉末あるいは
カルボキシルメチルセルロース等の水溶性粘結剤を炭素
質バインダーにして、Ｎ-メチルピロリドン（ＮＭ
Ｐ）、ジメチルホルムアミド、あるいは水、アルコール
等の溶媒を用いて、混合することにより、スラリーを作
成し、集電体上に塗布、乾燥することにより、成型する
こともできる。As a method for forming a negative electrode by using the material for a negative electrode of a lithium secondary battery of the present invention as an active material, the performance of the material for a negative electrode of a lithium secondary battery of the present invention is sufficiently brought out and the shapeability is high. It does not limit this as long as it is chemically and electrochemically stable. For example, there is a method of adding a powder or dispersion solution of a fluororesin such as polytetrafluoroethylene to the material for a negative electrode of a lithium secondary battery of the present invention, followed by mixing and kneading. Further, the negative electrode material of the lithium secondary battery of the present invention may be made of N-methylpyrrolidone (NM) by using a fluorocarbon resin powder such as polyvinylidene fluoride (PVdF) or a water-soluble binder such as carboxymethyl cellulose as a carbonaceous binder.
A slurry can be prepared by mixing with P), dimethylformamide, or a solvent such as water or alcohol, and applied to a current collector and dried to form a slurry.

【００３９】本発明の負極活物質は、正極活物質と非水
系電解質（例えば、有機溶媒系電解質）と適宜に組み合
わせて用いることができるが、これらの非水系電解質
（例えば、有機溶媒系電解質）や正極活物質は、リチウ
ム二次電池に通常用いることのできるものであれば、特
にこれを制限するものではない。The negative electrode active material of the present invention can be appropriately used in combination with a positive electrode active material and a non-aqueous electrolyte (for example, an organic solvent-based electrolyte). These non-aqueous electrolytes (for example, an organic solvent-based electrolyte) can be used. The positive electrode active material is not particularly limited as long as it can be generally used for a lithium secondary battery.

【００４０】正極活物質としては、例えば、リチウム含
有遷移金属酸化物ＬｉＭ（１）xＯ2（式中、ｘは０≦ｘ
≦１の範囲の数値であり、式中、Ｍ（１）は遷移金属を
表し、Ｃｏ、Ｎｉ、Ｍｎ、Ｔｉ、Ｃｒ、Ｖ、Ｆｅ、Ｚ
ｎ、Ａｌ、Ｓｎ、Ｉｎのうち少なくとも１種類からな
る）、或いは、ＬｉＭ（１）yＭ（２）2-yＯ4（式中、
ｙは０≦ｙ≦１の範囲の数値であり、式中、Ｍ（１）、
Ｍ（２）は遷移金属を表し、Ｃｏ、Ｎｉ、Ｍｎ、Ｔｉ、
Ｃｒ、Ｖ、Ｆｅ、Ｚｎ、Ａｌ、Ｓｎ、Ｉｎのうち少なく
とも１種類からなる）、遷移金属カルコゲン化物（Ｔｉ
Ｓ2、ＮｂＳｅ3、等）、バナジウム酸化物（Ｖ2Ｏ5、Ｖ
6Ｏ13、Ｖ2Ｏ4、Ｖ3Ｏ8、等）及びそのリチウム化合
物、一般式ＭxＭｏ6Ｃｈ8-y（式中、ｘは０≦ｘ≦４、
ｙは０≦ｙ≦１の範囲の数値であり、式中、Ｍは遷移金
属をはじめとする金属、Ｃｈはカルコゲン元素を表す）
で表されるシュブレル相化合物、或いは活性炭、活性炭
素繊維、等を用いることができる。As the positive electrode active material, for example, a lithium-containing transition metal oxide LiM (1) x O 2 (where x is 0 ≦ x
≦ 1 where M (1) represents a transition metal and Co, Ni, Mn, Ti, Cr, V, Fe, Z
n, Al, Sn, or In) or LiM (1) y M (2) 2-y O 4 (wherein
y is a numerical value in the range of 0 ≦ y ≦ 1, where M (1),
M (2) represents a transition metal, and Co, Ni, Mn, Ti,
Cr, V, Fe, Zn, Al, Sn, and In), and transition metal chalcogenides (Ti
S 2 , NbSe 3 , etc.), vanadium oxide (V 2 O 5 , V
6 O 13 , V 2 O 4 , V 3 O 8 , etc.) and lithium compounds thereof, general formula M x Mo 6 Ch 8-y (where x is 0 ≦ x ≦ 4,
y is a numerical value in the range of 0 ≦ y ≦ 1, where M represents a metal including a transition metal, and Ch represents a chalcogen element.
Or an activated carbon, an activated carbon fiber, or the like.

【００４１】非水系電解質（例えば、有機溶媒系電解
質）における有機溶媒としては、特に制限されるもので
はないが、例えば、プロピレンカーボネート、エチレン
カーボネート、ブチレンカーボネート、クロロエチレン
カーボネート、ジメチルカーボネート、ジエチルカーボ
ネート、エチルメチルカーボネート、１，１-ジメトキ
シエタン、１，２-ジメトキシエタン、１，２-ジエトキ
シエタン、γ-ブチロラクトン、テトラヒドロフラン、
２-メチルテトラヒドロフラン、１，３-ジオキソラン、
４-メチル-１，３-ジオキソラン、アニソール、ジエチ
ルエーテル、スルホラン、メチルスルホラン、アセトニ
トリル、クロロニトリル、プロピオニトリル、ホウ酸ト
リメチル、ケイ酸テトラメチル、ニトロメタン、ジメチ
ルホルムアミド、Ｎ-メチルピロリドン、酢酸エチル、
トリメチルオルトホルメート、ニトロベンゼン、塩化ベ
ンゾイル、臭化ベンゾイル、テトラヒドロチオフェン、
ジメチルスルホキシド、３-メチル-２-オキサゾリド
ン、エチレングリコール、サルファイト、ジメチルサル
ファイト、等の単独もしくは２種類以上の混合溶媒が使
用できる。The organic solvent in the non-aqueous electrolyte (for example, an organic solvent-based electrolyte) is not particularly limited, but for example, propylene carbonate, ethylene carbonate, butylene carbonate, chloroethylene carbonate, dimethyl carbonate, diethyl carbonate, Ethyl methyl carbonate, 1,1-dimethoxyethane, 1,2-dimethoxyethane, 1,2-diethoxyethane, γ-butyrolactone, tetrahydrofuran,
2-methyltetrahydrofuran, 1,3-dioxolan,
4-methyl-1,3-dioxolane, anisole, diethyl ether, sulfolane, methylsulfolane, acetonitrile, chloronitrile, propionitrile, trimethyl borate, tetramethyl silicate, nitromethane, dimethylformamide, N-methylpyrrolidone, ethyl acetate ,
Trimethyl orthoformate, nitrobenzene, benzoyl chloride, benzoyl bromide, tetrahydrothiophene,
A single solvent such as dimethyl sulfoxide, 3-methyl-2-oxazolidone, ethylene glycol, sulfite, dimethyl sulfite, or a mixture of two or more solvents can be used.

【００４２】電解質としては、従来より公知のものを何
れも使用することができ、例えば、ＬｉＣｌＯ4、Ｌｉ
ＢＦ4、ＬｉＰＦ6、ＬｉＡｓＦ6、ＬｉＢ（Ｃ6Ｈ5）、
ＬｉＣｌ、ＬｉＢｒ、ＬｉＣＦ3ＳＯ3、Ｌｉ（ＣＦ3Ｓ
Ｏ2）2Ｎ、Ｌｉ（ＣＦ3ＳＯ2）3Ｃ、Ｌｉ（ＣＦ3ＣＨ2
ＯＳＯ2）2Ｎ、Ｌｉ（ＣＦ3ＣＦ2ＣＨ2ＯＳＯ2）2Ｎ、
Ｌｉ（ＨＣＦ2ＣＦ2ＣＨ2ＯＳＯ2）2Ｎ、Ｌｉ（（Ｃ
Ｆ3）2ＣＨＯＳＯ2）2Ｎ、ＬｉＢ［Ｃ6Ｈ3（ＣＦ3）2］
4、等の１種または２種以上の混合物を挙げることがで
きる。As the electrolyte, any of conventionally known electrolytes can be used. For example, LiClO 4 , Li
BF 4 , LiPF 6 , LiAsF 6 , LiB (C 6 H 5 ),
LiCl, LiBr, LiCF 3 SO 3 , Li (CF 3 S
O 2 ) 2 N, Li (CF 3 SO 2 ) 3 C, Li (CF 3 CH 2
OSO 2 ) 2 N, Li (CF 3 CF 2 CH 2 OSO 2 ) 2 N,
Li (HCF 2 CF 2 CH 2 OSO 2 ) 2 N, Li ((C
F 3) 2 CHOSO 2) 2 N, LiB [C 6 H 3 (CF 3) 2]
And the like, or a mixture of two or more kinds.

【００４３】以上のように、本発明により、リチウム二
次電池負極用材料として、天然黒鉛等の鱗片状黒鉛の最
高水準の放電容量、もしくは黒鉛構造から決定される理
論容量と同程度の放電容量を持つと共に、かつ、充電初
期における副反応に起因する不可逆容量が小さく、大き
な充放電電流下で使用した場合でも高い放電容量が得ら
れる、等の優れた特性を示し、鱗片状黒鉛の問題を解決
したリチウム二次電池負極用材料、およびその製造方
法、並びにこれを用いたリチウム二次電池が工業的に提
供されるに至った。As described above, according to the present invention, as a negative electrode material for a lithium secondary battery, the discharge capacity at the highest level of flaky graphite such as natural graphite or the same as the theoretical capacity determined from the graphite structure. And has excellent characteristics such as a small irreversible capacity due to side reactions in the initial stage of charging, a high discharge capacity obtained even when used under a large charge / discharge current, and the like. The solved negative electrode material for a lithium secondary battery, a method for producing the same, and a lithium secondary battery using the same have been industrially provided.

【００４４】[0044]

【実施例】以下に本発明において、リチウム二次電池負
極用材料の構造、製造法の規定に用いた各種物性値の表
現方法、測定方法を示す。In the following, in the present invention, the structure of the material for the negative electrode of a lithium secondary battery, the method of expressing various physical properties used in the regulation of the production method, and the measuring method are shown.

【００４５】（１） 黒鉛化度（ｄ002、Ｌｃ） 単色のＸ線を平行ビームにコリメートし、高純度シリコ
ンを内部標準として加えた炭素粉末に照射し、黒鉛の
（００２）面に対応するピークを測定する。そのピーク
の位置及び半値幅を、内部標準のシリコンのピークを標
準として補正することにより、層面間の間隔ｄ002及び
結晶子のＣ軸方向の大きさＬｃを算出する。具体的な評
価方法は、日本学術振興会第１１７委員会にて規定され
ているものに準拠した。(1) Graphitization degree (d 002 , Lc) Monochromatic X-rays are collimated into a parallel beam and irradiated on a carbon powder to which high-purity silicon is added as an internal standard to correspond to the (002) plane of graphite. Measure the peak. The peak position and half width are corrected using the internal standard silicon peak as a standard to calculate the distance d 002 between the layer planes and the size Lc of the crystallite in the C-axis direction. The specific evaluation method was based on the one prescribed by the 117th Committee of the Japan Society for the Promotion of Science.

【００４６】（２） 比表面積 窒素ガス吸着によるＢＥＴ法によって測定した。(2) Specific surface area Measured by the BET method using nitrogen gas adsorption.

【００４７】（３） 電極作製及び電極性能測定 ポリフッ化ビニリデンのＮＭＰ（Ｎ-メチル-２-ピロリ
ドン）溶液に、リチウム二次電池負極用材料粉末とポリ
フッ化ビニリデンが質量比で９５対５となるように加え
て混練し、これを厚さ２０μｍの銅箔に塗布して、負極
電極箔を得た。この負極電極箔を、８０℃で乾燥してＮ
ＭＰを蒸発させた後、１０ｍｍ角に切り出して、負極電
極を作成した。この負極電極単極での電極特性を評価す
るために、対極、参照極にリチウム金属を用いた三極式
セルを用いた。電解液には、エチレンカーボネートとジ
エチルカーボネトの混合溶媒（体積比で１：１混合）
に、ＬｉＣｌＯ4を１ｍｏｌ／ｌの割合で溶解したもの
を用いた。充放電試験に関しては、電位規制の下、充
電、放電共に定電流密度（０．１ｍＡ／ｃｍ2）で行な
った。電位範囲は、０Ｖから１．５Ｖ（リチウム金属基
準）とした。初回充電容量、初回放電容量、初期充放電
効率を測定すると共に、２回目以後の充放電における放
電容量の変化の程度でサイクル特性を評価した。(3) Preparation of Electrode and Measurement of Electrode Performance In a NMP (N-methyl-2-pyrrolidone) solution of polyvinylidene fluoride, the mass ratio of the lithium secondary battery negative electrode material powder and polyvinylidene fluoride becomes 95: 5 by mass ratio. The mixture was kneaded, kneaded, and applied to a copper foil having a thickness of 20 μm to obtain a negative electrode foil. This negative electrode foil is dried at 80 ° C.
After evaporating the MP, a 10 mm square was cut out to form a negative electrode. In order to evaluate the electrode characteristics of the single electrode of the negative electrode, a three-electrode cell using lithium metal for the counter electrode and the reference electrode was used. In the electrolyte, a mixed solvent of ethylene carbonate and diethyl carbonate (1: 1 by volume ratio)
Used was dissolved LiClO 4 at a rate of 1 mol / l. Regarding the charge / discharge test, both charging and discharging were performed at a constant current density (0.1 mA / cm 2 ) under potential regulation. The potential range was 0 V to 1.5 V (based on lithium metal). The initial charge capacity, the initial discharge capacity, and the initial charge / discharge efficiency were measured, and the cycle characteristics were evaluated based on the degree of change in the discharge capacity in the second and subsequent charge / discharge.

【００４８】（実施例１）コークス粉末４ｋｇと鉄粉末
１２ｋｇを混合した後、黒鉛容器に入れ、これをタンマ
ン炉でアルゴン気流中で２０００℃に昇温加熱し、冷却
した。反応後に固形反応物を得た後、その表面部に析出
した粒状化合物約１ｋｇを回収した。これを濃塩酸１０
リットルに入れ、室温で１０時間保持した後に濾過し、
さらにこれを多量の水で洗浄濾過した後、大気中１２０
℃で２０時間乾燥して、中間生成物６００ｇを得た。得
られた中間生成物である粉末をジェットミルにて粉砕
し、空気分級機にて分級して、平均粒径１５μｍの粉末
生成物４００ｇを得た。この生成物の化学分析による金
属不純物の総計は、１．２質量％であった。また、この
粉末生成物の黒鉛化度は、ｄ002＝０．３３５５ｎｍ、
Ｌｃ＞１００ｎｍであり、高い黒鉛化度を有していた。Example 1 After mixing 4 kg of coke powder and 12 kg of iron powder, the mixture was placed in a graphite container, which was heated to 2,000 ° C. in an argon stream in a Tamman furnace and cooled. After obtaining a solid reactant after the reaction, about 1 kg of a granular compound precipitated on the surface thereof was recovered. This is concentrated hydrochloric acid 10
Liter, hold at room temperature for 10 hours, then filter,
After washing and filtering with a large amount of water,
Drying at 20 ° C. for 20 hours gave 600 g of the intermediate product. The obtained intermediate product powder was pulverized with a jet mill and classified with an air classifier to obtain 400 g of a powder product having an average particle size of 15 μm. The total amount of metal impurities by chemical analysis of this product was 1.2% by mass. The degree of graphitization of this powder product was d 002 = 0.3355 nm,
Lc> 100 nm and had a high degree of graphitization.

【００４９】この粉末黒鉛３００ｇに対し、コールター
ルピッチ（軟化点８０℃）１００ｇを混合し、２００
℃、１２０分間、Ｚ型ニーダーで捏合した。次第に粘度
を増し、造粒状態となった造粒物を冷却後解砕し、黒鉛
製の坩堝に入れ、リードハンマータイプの連続焼成炉
中、８００℃の温度で炭素化した。更に、これを黒鉛製
の坩堝に入れ、アチソンタイプの黒鉛化炉中３０００℃
で熱処理、黒鉛化した後、解砕、空気分級により、平均
粒径２７μｍの生成物３２０ｇを得た。100 g of coal tar pitch (softening point: 80 ° C.) was mixed with 300 g of the powdered graphite, and
The mixture was kneaded with a Z-type kneader at 120C for 120 minutes. The granulated material which gradually increased in viscosity and became granulated was cooled, crushed, put into a graphite crucible, and carbonized at a temperature of 800 ° C. in a continuous hammer of a lead hammer type. Further, this was put in a graphite crucible, and 3,000 ° C. in an Acheson type graphitization furnace.
After heat treatment and graphitization, 320 g of a product having an average particle size of 27 μm was obtained by crushing and air classification.

【００５０】得られた生成物の黒鉛化度は、ｄ002＝
０．３３５５ｎｍ、Ｌｃ＞１００ｎｍ、比表面積は１．
０ｍ2／ｇ、２０回タップ時のタップ密度が０．７３ｇ
／ｃｍ3、３００回タップ時のタップ密度が１．０４ｇ
／ｃｍ3であった。また、得られた生成物の化学分析に
よる金属不純物の総計は、０．２質量％であった。The degree of graphitization of the product obtained is d 002 =
0.3355 nm, Lc> 100 nm, specific surface area is 1.
0m 2 / g, tap density when tapping 20 times is 0.73g
/ Cm 3 , tap density when tapping 300 times is 1.04g
/ Cm 3 . The total amount of metal impurities by chemical analysis of the obtained product was 0.2% by mass.

【００５１】この材料の充放電特性は、初回充電容量が
３８４ｍＡｈ／ｇ、初回放電容量が３６８ｍＡｈ／ｇ
で、初期充放電効率は９６％という結果が得られた。ま
た、２回目以後の充放電においても、放電容量はほとん
ど変わらず、優れたサイクル特性を示すなど、高い電極
性能を有していた。The charge and discharge characteristics of this material were such that the initial charge capacity was 384 mAh / g and the initial discharge capacity was 368 mAh / g.
The result was that the initial charge / discharge efficiency was 96%. In addition, even in the second and subsequent charging and discharging, the discharge capacity was hardly changed and the electrode exhibited high electrode performance such as excellent cycle characteristics.

【００５２】（実施例２）製鉄プロセスの製鋼ダストと
して粉末２ｋｇを回収した。これを濃塩酸１０リットル
に入れ、室温で１２時間保持した後に濾過し、さらにこ
れを多量の水で洗浄濾過した後、１２０℃で１２時間乾
燥した。得られた中間生成物粉末をジェットミルにて粉
砕し、空気分級機にて分級して、平均粒径１０μｍの粉
末生成物８００ｇを得た。この生成物の化学分析による
金属不純物の総計は、２．１質量％であった。また、こ
の粉末生成物の黒鉛化度は、ｄ002＝０．３３５４ｎ
ｍ、Ｌｃ＞１００ｎｍであり、高い黒鉛化度を有してい
た。Example 2 2 kg of powder was recovered as steelmaking dust in the iron making process. This was put in 10 liters of concentrated hydrochloric acid, kept at room temperature for 12 hours, filtered, washed with a large amount of water, filtered, and dried at 120 ° C. for 12 hours. The obtained intermediate product powder was pulverized by a jet mill and classified by an air classifier to obtain 800 g of a powder product having an average particle size of 10 μm. The total amount of metal impurities by chemical analysis of this product was 2.1% by mass. The degree of graphitization of this powder product is d 002 = 0.3354 n
m, Lc> 100 nm, and had a high degree of graphitization.

【００５３】この粉末黒鉛４００ｇに対し、コールター
ルピッチ（軟化点８０℃）１２０ｇを混合し、２００
℃、１２０分間、Ｚ型ニーダーで捏合した。次第に粘度
を増し、造粒状態となった造粒物を冷却後解砕し、黒鉛
製の坩堝に入れ、リードハンマータイプの連続焼成炉
中、８００℃の温度で炭素化した。更に、これを黒鉛製
の坩堝に入れ、アチソンタイプの黒鉛化炉中３０００℃
で熱処理、黒鉛化した後、解砕、空気分級により、平均
粒径２５μｍの生成物３８０ｇを得た。120 g of coal tar pitch (softening point: 80 ° C.) was mixed with 400 g of this powdered graphite,
The mixture was kneaded with a Z-type kneader at 120C for 120 minutes. The granulated material which gradually increased in viscosity and became granulated was cooled, crushed, put into a graphite crucible, and carbonized at a temperature of 800 ° C. in a continuous hammer of a lead hammer type. Further, this was put in a graphite crucible, and 3,000 ° C. in an Acheson type graphitization furnace.
After heat treatment and graphitization, 380 g of a product having an average particle size of 25 μm was obtained by crushing and air classification.

【００５４】得られた生成物の黒鉛化度は、ｄ002＝
０．３３５５ｎｍ、Ｌｃ＞１００ｎｍ、比表面積は０．
８ｍ2／ｇ、２０回タップ時のタップ密度が０．９６ｇ
／ｃｍ3、３００回タップ時のタップ密度が１．１４ｇ
／ｃｍ3であった。また、得られた生成物の化学分析に
よる金属不純物の総計は、０．１質量％であった。The degree of graphitization of the product obtained is d 002 =
0.3355 nm, Lc> 100 nm, specific surface area is 0.1 mm.
8m 2 / g, tap density when tapping 20 times is 0.96g
/ Cm 3 , tap density when tapping 300 times is 1.14g
/ Cm 3 . Further, the total amount of metal impurities by chemical analysis of the obtained product was 0.1% by mass.

【００５５】この材料の充放電特性は、初回充電容量が
３８７ｍＡｈ／ｇ、初回放電容量が３７１ｍＡｈ／ｇ
で、初期充放電効率は９６％という結果が得られた。ま
た、２回目以後の充放電においても、放電容量はほとん
ど変わらず、優れたサイクル特性を示すなど、高い電極
性能を有していた。The charge and discharge characteristics of this material were such that the initial charge capacity was 387 mAh / g and the initial discharge capacity was 371 mAh / g.
The result was that the initial charge / discharge efficiency was 96%. In addition, even in the second and subsequent charging and discharging, the discharge capacity was hardly changed and the electrode exhibited high electrode performance such as excellent cycle characteristics.

【００５６】（実施例３）製鉄プロセスの製鋼ダストと
して粉末１０ｋｇを回収した。これを濃塩酸５０リット
ルに入れ、室温で１２時間保持した後に濾過し、さらに
これを多量の水で洗浄濾過した後、１２０℃で１２時間
乾燥した。得られた粉末をジェットミルで粉砕した後に
空気分級を行って、平均粒径１２μｍの粉末生成物３．
６ｋｇを得た。この生成物の化学分析による金属不純物
の総計は、２．１質量％であった。また、この粉末生成
物の黒鉛化度は、ｄ002＝０．３３５６ｎｍ、Ｌｃ＞１
００ｎｍであり、高い黒鉛化度を有していた。Example 3 10 kg of powder was recovered as steelmaking dust in the iron making process. This was put into 50 liters of concentrated hydrochloric acid, kept at room temperature for 12 hours, filtered, washed with a large amount of water, filtered and dried at 120 ° C. for 12 hours. 2. The obtained powder was pulverized by a jet mill and then subjected to air classification to obtain a powder product having an average particle size of 12 μm.
6 kg were obtained. The total amount of metal impurities by chemical analysis of this product was 2.1% by mass. The degree of graphitization of this powder product was d 002 = 0.3356 nm, Lc> 1.
00 nm and had a high degree of graphitization.

【００５７】この粉末黒鉛２ｋｇに対し、コールタール
ピッチ（軟化点８０℃）０．６６ｋｇを混合し、２００
℃、１２０分間、Ｚ型ニーダーで捏合した。次第に粘度
を増し、造粒状態となった造粒物を冷却後解砕し、黒鉛
製の坩堝に入れ、マッフル炉を用いて、アルゴン雰囲気
下１４００℃の温度で炭素化した。更にこれを解砕、空
気分級し、平均粒径２６μｍの生成物１．８ｋｇを得
た。To 2 kg of this powdered graphite, 0.66 kg of coal tar pitch (softening point: 80 ° C.) was mixed,
The mixture was kneaded with a Z-type kneader at 120C for 120 minutes. The granulated material which gradually increased in viscosity and became granulated was cooled, crushed, put into a graphite crucible, and carbonized at 1400 ° C. in an argon atmosphere using a muffle furnace. This was further crushed and classified by air to obtain 1.8 kg of a product having an average particle size of 26 μm.

【００５８】得られた生成物の黒鉛化度は、ｄ002＝
０．３３５６ｎｍ、Ｌｃ＞１００ｎｍ、比表面積は１．
２ｍ2／ｇ、２０回タップ時のタップ密度が０．７２ｇ
／ｃｍ3、３００回タップ時のタップ密度が０．９７ｇ
／ｃｍ3であった。また、得られた生成物の化学分析に
よる金属不純物の総計は、０．５質量％であった。The degree of graphitization of the product obtained is d 002 =
0.3356 nm, Lc> 100 nm, specific surface area is 1.
2m 2 / g, tap density when tapping 20 times is 0.72g
/ Cm 3 , tap density after tapping 300 times is 0.97g
/ Cm 3 . Further, the total amount of metal impurities by chemical analysis of the obtained product was 0.5% by mass.

【００５９】この材料の充放電特性は、初回充電容量が
３７３ｍＡｈ／ｇ、初回放電容量が３５４ｍＡｈ／ｇ
で、初期充放電効率は９５％という結果が得られた。ま
た、２回目以後の充放電においても、放電容量はほとん
ど変わらず、優れたサイクル特性を示すなど、高い電極
性能を有していた。The charge / discharge characteristics of this material were such that the initial charge capacity was 373 mAh / g and the initial discharge capacity was 354 mAh / g.
The result obtained was that the initial charge / discharge efficiency was 95%. In addition, even in the second and subsequent charging and discharging, the discharge capacity was hardly changed and the electrode exhibited high electrode performance such as excellent cycle characteristics.

【００６０】（実施例４）コークス粉末３ｋｇとニッケ
ル粉末１２ｋｇを混合した後、黒鉛容器に入れ、これを
タンマン炉でアルゴン気流中２２００℃に昇温加熱し、
冷却した。反応後に固形反応物を得た後、その表面部に
析出した粒状化合物約７５０ｇを回収した。これを濃硝
酸とフッ酸の１：１混合溶液１リットルに入れ、室温で
１２時間保持した後に濾過し、さらに、これを多量の水
で洗浄濾過した後、１２０℃で１２時間乾燥した。得ら
れた粉末をジェットミルで粉砕した後、篩分級して平均
粒径１２μｍの粉末生成物３７０ｇを得た。この生成物
の化学分析による金属不純物の総計は、１．９質量％で
あった。また、この粉末生成物の黒鉛化度は、ｄ002＝
０．３３５５ｎｍ、Ｌｃ＞１００ｎｍであり、高い黒鉛
化度を有していた。Example 4 After mixing 3 kg of coke powder and 12 kg of nickel powder, the mixture was placed in a graphite container, and this was heated to 2200 ° C. in an argon stream with a Tamman furnace, and heated.
Cool. After obtaining a solid reaction product after the reaction, about 750 g of a granular compound precipitated on the surface thereof was recovered. This was put in 1 liter of a 1: 1 mixed solution of concentrated nitric acid and hydrofluoric acid, kept at room temperature for 12 hours, filtered, washed with a large amount of water, filtered and dried at 120 ° C. for 12 hours. The obtained powder was pulverized by a jet mill and then classified by a sieve to obtain 370 g of a powder product having an average particle size of 12 μm. The total amount of metal impurities by chemical analysis of this product was 1.9% by mass. The degree of graphitization of this powder product is d 002 =
0.3355 nm, Lc> 100 nm, and had a high degree of graphitization.

【００６１】この粉末黒鉛３００ｇに対し、コールター
ルピッチ（軟化点８０℃）１５０ｇを混合し、２００
℃、１２０分間、Ｚ型ニーダーで捏合した。次第に粘度
を増し、造粒状態となった造粒物を冷却後解砕し、黒鉛
製の坩堝に入れ、リードハンマータイプの連続焼成炉
中、８００℃の温度で炭素化した。更に、これを黒鉛製
の坩堝に入れ、アチソンタイプの黒鉛化炉中３０００℃
で熱処理、黒鉛化した後、解砕、空気分級により、平均
粒径２５μｍの生成物２９０ｇを得た。To 300 g of the graphite powder, 150 g of coal tar pitch (softening point: 80 ° C.) was mixed,
The mixture was kneaded with a Z-type kneader at 120C for 120 minutes. The granulated material which gradually increased in viscosity and became granulated was cooled, crushed, put into a graphite crucible, and carbonized at a temperature of 800 ° C. in a continuous hammer of a lead hammer type. Further, this was put in a graphite crucible, and 3,000 ° C. in an Acheson type graphitization furnace.
After heat treatment and graphitization, 290 g of a product having an average particle size of 25 μm was obtained by crushing and air classification.

【００６２】得られた生成物の黒鉛化度は、ｄ002＝
０．３３５５ｎｍ、Ｌｃ＞１００ｎｍ、比表面積は１．
１ｍ2／ｇ、２０回タップ時のタップ密度が０．７４ｇ
／ｃｍ3、３００回タップ時のタップ密度が０．９７ｇ
／ｃｍ3であった。また、得られた生成物の化学分析に
よる金属不純物の総計は、０．６質量％であった。The degree of graphitization of the product obtained is d 002 =
0.3355 nm, Lc> 100 nm, specific surface area is 1.
1m 2 / g, tap density at the time of 20 taps is 0.74g
/ Cm 3 , tap density after tapping 300 times is 0.97g
/ Cm 3 . The total amount of metal impurities by chemical analysis of the obtained product was 0.6% by mass.

【００６３】この材料の充放電特性は、初回充電容量が
３８６ｍＡｈ／ｇ、初回放電容量が３７０ｍＡｈ／ｇ
で、初期充放電効率は９６％という結果が得られた。ま
た、２回目以後の充放電においても、放電容量はほとん
ど変わらず、優れたサイクル特性を示すなど、高い電極
性能を有していた。The charge and discharge characteristics of this material were such that the initial charge capacity was 386 mAh / g and the initial discharge capacity was 370 mAh / g.
The result was that the initial charge / discharge efficiency was 96%. In addition, even in the second and subsequent charging and discharging, the discharge capacity was hardly changed and the electrode exhibited high electrode performance such as excellent cycle characteristics.

【００６４】（実施例５）コークス粉末１ｋｇとシリコ
ン粉末８ｋｇを混合した後、黒鉛容器に入れ、これをタ
ンマン炉でアルゴン気流中で２５００℃に昇温加熱し、
冷却した。反応後に固形反応物を得た後、その表面部に
析出した粒状化合物約６００ｇを回収した。これを濃硝
酸とフッ酸の１：１混合溶液１リットルに入れ、室温で
１２時間保持した後に濾過し、さらに、これを多量の水
で洗浄濾過した後、１２０℃で１２時間乾燥した。得ら
れた粉末をボールミルで粉砕した後、篩分級して平均粒
径１５μｍの粉末生成物３５０ｇを得た。この生成物の
化学分析による金属不純物の総計は、７．５質量％であ
った。Example 5 After mixing 1 kg of coke powder and 8 kg of silicon powder, the mixture was placed in a graphite container, and this was heated to 2500 ° C. in an argon stream in a Tamman furnace, and heated.
Cool. After obtaining a solid reaction product after the reaction, about 600 g of a granular compound precipitated on the surface thereof was recovered. This was put in 1 liter of a 1: 1 mixed solution of concentrated nitric acid and hydrofluoric acid, kept at room temperature for 12 hours, filtered, washed with a large amount of water, filtered and dried at 120 ° C. for 12 hours. The obtained powder was pulverized with a ball mill and then classified by sieve to obtain 350 g of a powder product having an average particle size of 15 μm. The total amount of metal impurities by chemical analysis of this product was 7.5% by mass.

【００６５】この粉末黒鉛３００ｇに対し、コールター
ルピッチ（軟化点８０℃）９０ｇを混合し、２００℃、
１２０分間、Ｚ型ニーダーで捏合した。次第に粘度を増
し、造粒状態となった造粒物を冷却後解砕し、黒鉛製の
坩堝に入れ、リードハンマータイプの連続焼成炉中８０
０℃の温度で炭素化した。更に、これを黒鉛製の坩堝に
入れ、アチソンタイプの黒鉛化炉中３０００℃で熱処
理、黒鉛化した後、解砕、空気分級により、平均粒径２
２μｍの生成物３７０ｇを得た。90 g of coal tar pitch (softening point: 80 ° C.) is mixed with 300 g of this powdered graphite,
It was kneaded with a Z-type kneader for 120 minutes. After gradually increasing the viscosity, the granulated material in a granulated state is cooled and then crushed, placed in a graphite crucible, and placed in a continuous hammer of a lead hammer type.
Carbonized at a temperature of 0 ° C. Further, this was put into a graphite crucible, heat-treated at 3000 ° C. in an Acheson type graphitization furnace, graphitized, then crushed and classified with air to obtain an average particle size of 2%.
370 g of a 2 μm product were obtained.

【００６６】得られた生成物の黒鉛化度は、ｄ002＝
０．３３５５ｎｍ、Ｌｃ＞１００ｎｍ、比表面積は１．
０ｍ2／ｇ、２０回タップ時のタップ密度が０．９６ｇ
／ｃｍ3、３００回タップ時のタップ密度が１．１４ｇ
／ｃｍ3であった。また、得られた生成物の化学分析に
よる金属不純物の総計は、０．１質量％であった。The degree of graphitization of the product obtained is d 002 =
0.3355 nm, Lc> 100 nm, specific surface area is 1.
0m 2 / g, tap density when tapping 20 times is 0.96g
/ Cm 3 , tap density when tapping 300 times is 1.14g
/ Cm 3 . Further, the total amount of metal impurities by chemical analysis of the obtained product was 0.1% by mass.

【００６７】この材料の充放電特性は、初回充電容量が
３８０ｍＡｈ／ｇ、初回放電容量が３６１ｍＡｈ／ｇ
で、初期充放電効率は９５％という結果が得られた。ま
た、２回目以後の充放電においても、放電容量はほとん
ど変わらず、優れたサイクル特性を示すなど、高い電極
性能を有していた。The charge and discharge characteristics of this material were such that the initial charge capacity was 380 mAh / g and the initial discharge capacity was 361 mAh / g.
The result obtained was that the initial charge / discharge efficiency was 95%. In addition, even in the second and subsequent charging and discharging, the discharge capacity was hardly changed and the electrode exhibited high electrode performance such as excellent cycle characteristics.

【００６８】（実施例６）コークス粉末２ｋｇとコバル
ト粉末８ｋｇを混合した後、黒鉛容器に入れ、これをタ
ンマン炉でアルゴン気流中で２２００℃に昇温加熱し、
冷却した。反応後に固形反応物を得た後、その表面部に
析出した粒状化合物約４００ｇを回収した。これを濃硝
酸とフッ酸の１：１混合溶液１リットルに入れ、室温で
１２時間保持した後に濾過し、さらにこれを多量の水で
洗浄濾過した後、１２０℃１２時間乾燥した。得られた
粉末をジェットミルで粉砕した後、篩分級して平均粒径
３８μｍの粉末生成物５ｇを得た。この生成物の化学分
析による金属不純物の総計は、１．５質量％であった。Example 6 After mixing 2 kg of coke powder and 8 kg of cobalt powder, the mixture was placed in a graphite container, and this was heated to 2200 ° C. in an argon stream in a Tamman furnace, and heated.
Cool. After obtaining a solid reactant after the reaction, about 400 g of a granular compound precipitated on the surface thereof was recovered. This was put into 1 liter of a 1: 1 mixed solution of concentrated nitric acid and hydrofluoric acid, kept at room temperature for 12 hours, filtered, washed with a large amount of water, filtered and dried at 120 ° C. for 12 hours. The obtained powder was pulverized by a jet mill and then sieved to obtain 5 g of a powder product having an average particle size of 38 μm. The total metal impurities by chemical analysis of the product was 1.5% by weight.

【００６９】このようにして調製した炭素材２００ｇに
対し、コールタールピッチ（軟化点８０℃）６７ｇを混
合し、以下実施例１と同様の手法により、炭化、黒鉛
化、解砕、分級を行い、平均粒径２５μｍの生成物２２
０ｇを得た。To 200 g of the carbon material thus prepared, 67 g of coal tar pitch (softening point: 80 ° C.) was mixed, and carbonization, graphitization, crushing, and classification were performed in the same manner as in Example 1. Product 22 having an average particle size of 25 μm
0 g was obtained.

【００７０】得られた生成物の黒鉛化度は、ｄ002＝
０．３３５５ｎｍ、Ｌｃ＞１００ｎｍ、比表面積は１．
０ｍ2／ｇ、２０回タップ時のタップ密度が０．７３ｇ
／ｃｍ3、３００回タップ時のタップ密度が０．９８ｇ
／ｃｍ3であった。また、得られた生成物の化学分析に
よる金属不純物の総計は、０．１質量％であった。The degree of graphitization of the product obtained is d 002 =
0.3355 nm, Lc> 100 nm, specific surface area is 1.
0m 2 / g, tap density when tapping 20 times is 0.73g
/ Cm 3 , tap density when tapping 300 times is 0.98g
/ Cm 3 . Further, the total amount of metal impurities by chemical analysis of the obtained product was 0.1% by mass.

【００７１】この材料の充放電特性は、初回充電容量が
３７６ｍＡｈ／ｇ、初回放電容量が３６０ｍＡｈ／ｇ
で、初期充放電効率は９６％という結果が得られた。ま
た、２回目以後の充放電においても、放電容量はほとん
ど変わらず、優れたサイクル特性を示すなど、高い電極
性能を有していた。The charge and discharge characteristics of this material were such that the initial charge capacity was 376 mAh / g, and the initial discharge capacity was 360 mAh / g.
The result was that the initial charge / discharge efficiency was 96%. In addition, even in the second and subsequent charging and discharging, the discharge capacity was hardly changed and the electrode exhibited high electrode performance such as excellent cycle characteristics.

【００７２】（比較例１）天然黒鉛をボールミルにて粉
砕した後篩分級し、平均粒径１５μｍの粉末を得た。こ
の黒鉛の金属不純物の総計は、０．４質量％であり、黒
鉛化度は、ｄ002＝０．３３５５ｎｍ、Ｌｃ＞１００ｎ
ｍと高い黒鉛化度を有していた。この天然黒鉛粉末３０
０ｇに対し、コールタールピッチ（軟化点８０℃）を５
０ｇを混合し、２００℃、１２０分間、Ｚ型ニーダーで
捏合した。次第に粘度を増し、造粒状態となった造粒物
を冷却後解砕し、黒鉛製の坩堝に入れ、リードハンマー
タイプの連続焼成炉中８００℃の温度で炭素化した。こ
れを平均粒径２５μｍに粒度調製し、黒鉛製坩堝に入
れ、アチソンタイプの黒鉛化炉中３０００℃で熱処理、
黒鉛化した。Comparative Example 1 Natural graphite was pulverized with a ball mill and classified by sieving to obtain a powder having an average particle size of 15 μm. The total amount of metal impurities in this graphite was 0.4% by mass, and the degree of graphitization was d 002 = 0.3355 nm, Lc> 100 n
m and a high degree of graphitization. This natural graphite powder 30
5 g of coal tar pitch (softening point 80 ° C)
Then, the mixture was kneaded with a Z-type kneader at 200 ° C. for 120 minutes. The granulated material which gradually increased in viscosity and became granulated was cooled, crushed, placed in a graphite crucible, and carbonized at a temperature of 800 ° C. in a continuous hammer of a lead hammer type. This was adjusted to an average particle size of 25 μm, placed in a graphite crucible, and heat-treated at 3000 ° C. in an Acheson type graphitization furnace.
Graphitized.

【００７３】得られた生成物の黒鉛化度は、ｄ002＝
０．３３５５ｎｍ、Ｌｃ＞１００ｎｍ、比表面積は１．
７ｍ2／ｇ、２０回タップ時のタップ密度が０．６８ｇ
／ｃｍ3、３００回タップ時のタップ密度が０．７７ｇ
／ｃｍ3であった。また、得られた生成物の化学分析に
よる金属不純物の総計は、０．１質量％であった。The degree of graphitization of the product obtained is d 002 =
0.3355 nm, Lc> 100 nm, specific surface area is 1.
7m 2 / g, tap density after tapping 20 times is 0.68g
/ Cm 3 , Tap density at tapping 300 times is 0.77g
/ Cm 3 . Further, the total amount of metal impurities by chemical analysis of the obtained product was 0.1% by mass.

【００７４】この材料の充放電特性は、初回充電容量が
３９０ｍＡｈ／ｇ、初回放電容量が３４５ｍＡｈ／ｇ
で、初期充放電効率は８８％という結果であった。The charge and discharge characteristics of this material were such that the initial charge capacity was 390 mAh / g and the initial discharge capacity was 345 mAh / g.
As a result, the initial charge / discharge efficiency was 88%.

【００７５】（比較例２）実施例２と同じ製鉄プロセス
の製鋼ダスト２ｋｇを回収した。これを実施例２と同様
の方法で、濃塩酸洗浄、水洗浄、乾燥、粉砕、分級を行
って、平均粒径１０μｍの粉末生成物８００ｇを得た。
この生成物の化学分析による金属不純物の総計は、２．
２質量％であった。また、この粉末生成物の黒鉛化度
は、ｄ002＝０．３３５６ｎｍ、Ｌｃ＞１００ｎｍであ
り、高い黒鉛化度を有していた。(Comparative Example 2) 2 kg of steelmaking dust obtained by the same iron making process as in Example 2 was recovered. This was washed with concentrated hydrochloric acid, washed with water, dried, pulverized, and classified in the same manner as in Example 2 to obtain 800 g of a powder product having an average particle size of 10 μm.
The total amount of metal impurities by chemical analysis of this product was 2.
It was 2% by mass. The degree of graphitization of this powder product was d 002 = 0.3356 nm, Lc> 100 nm, and had a high degree of graphitization.

【００７６】この粉末黒鉛４００ｇに対し、コールター
ルピッチ（軟化点８０℃）１２０ｇを混合し、２００
℃、１２０分間、Ｚ型ニーダーで捏合した。次第に粘度
を増し、造粒状態となった造粒物を冷却後解砕し、黒鉛
製の坩堝に入れ、実験炉にて窒素雰囲気中６００℃の温
度で、熱処理を行った。更にこれを、解砕、空気分級に
より、平均粒径２５μｍの生成物４８０ｇを得た。120 g of coal tar pitch (softening point: 80 ° C.) was mixed with 400 g of the powdered graphite,
The mixture was kneaded with a Z-type kneader at 120C for 120 minutes. The granulated material gradually increased in viscosity and formed into a granulated state was cooled and then crushed, placed in a graphite crucible, and heat-treated at a temperature of 600 ° C. in a nitrogen atmosphere in a laboratory furnace. This was further crushed and classified by air to obtain 480 g of a product having an average particle size of 25 μm.

【００７７】得られた生成物の黒鉛化度は、ｄ002＝
０．３３６０ｎｍ、Ｌｃ＞１００ｎｍ、比表面積は１１
ｍ2／ｇ、２０回タップ時のタップ密度が０．５６ｇ／
ｃｍ3、３００回タップ時のタップ密度が０．７０ｇ／
ｃｍ3であった。また、得られた生成物の化学分析によ
る金属不純物の総計は、２．１質量％であった。The degree of graphitization of the product obtained is d 002 =
0.3360 nm, Lc> 100 nm, specific surface area is 11
m 2 / g, tap density at the time of 20 taps is 0.56 g /
cm 3 , tap density at the time of 300 taps is 0.70 g /
cm 3 . The total amount of metal impurities by chemical analysis of the obtained product was 2.1% by mass.

【００７８】この材料の充放電特性は、初回充電容量が
３４９ｍＡｈ／ｇ、初回放電容量が２９７ｍＡｈ／ｇ
で、初期充放電効率は８５％という結果が得られた。ま
た、２回目以降の充放電において、放電容量が徐々に減
少し、３０回の充放電後では、第１回目の放電容量に比
べて２０％程度の劣化が認められた。The charge and discharge characteristics of this material were such that the initial charge capacity was 349 mAh / g and the initial discharge capacity was 297 mAh / g.
The result was that the initial charge / discharge efficiency was 85%. Further, in the second and subsequent charge / discharge, the discharge capacity gradually decreased, and after 30 charge / discharge cycles, a deterioration of about 20% was recognized as compared to the first discharge capacity.

【００７９】比較例１、２で得られた黒鉛材の性能を、
実施例１〜６と比較すると、本発明の黒鉛材の方が、放
電容量、初期充放電効率、サイクル特性の電極特性は優
れていることが分かる。The performance of the graphite materials obtained in Comparative Examples 1 and 2 was
Compared with Examples 1 to 6, it can be seen that the graphite material of the present invention has better discharge capacity, initial charge / discharge efficiency, and electrode characteristics such as cycle characteristics.

【００８０】[0080]

【発明の効果】本発明により、リチウム二次電池負極用
炭素材料として、天然黒鉛等の鱗片状黒鉛の最高水準の
放電容量、もしくは黒鉛構造から決定される理論容量と
同程度の放電容量を持つと共に、かつ充電初期における
副反応に起因する不可逆容量が大きく、大きな充放電電
流下で使用した場合に高い放電容量が得られない等の鱗
片状黒鉛の問題を解決したリチウム二次電池負極用材料
およびその製造方法が提供された。また、高容量で充放
電効率の高い負極材料を用いた本発明のリチウム二次電
池により、携帯機器等のさらなる小型・軽量化や長時間
の使用が可能となった。According to the present invention, the carbon material for a negative electrode of a lithium secondary battery has the highest discharge capacity of flaky graphite such as natural graphite or the same discharge capacity as the theoretical capacity determined from the graphite structure. A material for negative electrodes of lithium secondary batteries that solves the problem of flaky graphite, such as having a large irreversible capacity due to side reactions in the initial stage of charging and not being able to obtain a high discharge capacity when used under a large charge / discharge current. And a method of manufacturing the same. Further, the lithium secondary battery of the present invention using a negative electrode material having high capacity and high charge / discharge efficiency has made it possible to further reduce the size and weight of portable devices and the like and to use them for a long time.

───────────────────────────────────────────────────── フロントページの続き (72)発明者 天橋 弘明 京都府福知山市長田野町３丁目26番地 株 式会社エスイーシー京都工場内 (72)発明者 鶴本 照啓 京都府福知山市長田野町３丁目26番地 株 式会社エスイーシー京都工場内 (72)発明者 河野 太郎 東京都千代田区大手町２−６−３ 新日本 製鐵株式会社内 (72)発明者 杉浦 勉 千葉県富津市新富20−１ 新日本製鐵株式 会社技術開発本部内 (72)発明者 濱田 健 千葉県富津市新富20−１ 新日本製鐵株式 会社技術開発本部内 (72)発明者 莊司 浩雅 千葉県富津市新富20−１ 新日本製鐵株式 会社技術開発本部内 Ｆターム(参考） 4G046 CA06 CA07 CB02 CB09 CC01 EA01 EA02 EB04 EC02 EC06 5H029 AJ03 AK03 AL07 AM03 AM04 AM05 AM07 BJ02 BJ14 CJ02 CJ30 DJ16 HJ05 HJ07 HJ08 HJ14 5H050 AA08 BA17 CA08 CB08 EA10 EA24 GA02 GA05 GA29 HA05 HA07 HA08 HA14  ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Hiroaki Amanohashi 3-26, Nagano-cho, Fukuchiyama-shi, Kyoto, Japan Inside the SSC Kyoto Plant (72) Inventor Teruhiro Tsurumoto 3-26, Nagatano-cho, Fukuchiyama-shi, Kyoto, Japan (72) Inventor Taro Kono 2-6-3 Otemachi, Chiyoda-ku, Tokyo Nippon Steel Corporation (72) Inventor Tsutomu Sugiura 20-1 Shintomi, Futtsu-shi, Chiba Nippon Steel Corporation In-house Technology Development Division (72) Inventor Ken Hamada 20-1 Shintomi, Futtsu-shi, Chiba Nippon Steel Corporation In-house Technology Development Division (72) Hiromasa Souji 20-1 Shintomi, Futtsu-shi, Chiba Nippon Steel Corporation 4G046 CA06 CA07 CB02 CB09 CC01 EA01 EA02 EB04 EC02 EC06 5H029 AJ03 AK03 AL07 AM03 AM04 AM05 AM07 BJ0 2 BJ14 CJ02 CJ30 DJ16 HJ05 HJ07 HJ08 HJ14 5H050 AA08 BA17 CA08 CB08 EA10 EA24 GA02 GA05 GA29 HA05 HA07 HA08 HA14

Claims (12)

【特許請求の範囲】[Claims] 【請求項１】 金属と炭素の溶融状態の冷却過程に析出
した炭素を処理して得られる炭素含有量が９０質量％以
上の黒鉛と、炭素質バインダーとの捏合物を、熱処理し
てなる炭素材料であって、該炭素材料の平均粒径が５μ
ｍ以上１００μｍ未満、かつ２０回タップ時のタップ密
度が０．７０ｇ／ｃｍ3以上であることを特徴とするリ
チウム二次電池負極用材料。1. A carbon material obtained by heat-treating a kneaded product of graphite having a carbon content of 90% by mass or more and a carbonaceous binder obtained by treating carbon precipitated in a cooling process in a molten state of metal and carbon. A carbon material having an average particle size of 5 μm.
A material for a negative electrode of a lithium secondary battery, characterized in that the tap density at the time of 20 taps is 0.70 g / cm 3 or more. 【請求項２】 前記捏合物の炭素質バインダーが、熱処
理により炭素化物になっていることを特徴とする請求項
１記載のリチウム二次電池負極用材料。2. The material for a negative electrode of a lithium secondary battery according to claim 1, wherein the carbonaceous binder of the kneaded material has been turned into a carbonized material by heat treatment. 【請求項３】 前記炭素材料が、黒鉛化物であることを
特徴とする請求項１記載のリチウム二次電池負極用材
料。3. The negative electrode material for a lithium secondary battery according to claim 1, wherein the carbon material is a graphitized material. 【請求項４】 前記炭素材料の３００回タップ時のタッ
プ密度が０．８５ｇ／ｃｍ3以上であることを特徴とす
る請求項１〜３の何れか１項に記載のリチウム二次電池
負極用材料。4. The negative electrode for a lithium secondary battery according to claim 1, wherein the tap density of the carbon material at 300 taps is 0.85 g / cm 3 or more. material. 【請求項５】 前記炭素材料の炭素含有量が９９質量％
以上で、ＢＥＴ法による比表面積が５ｍ2／ｇ以下であ
ることを特徴とする請求項１〜４の何れか１項に記載の
リチウム二次電池負極用材料。5. The carbon material has a carbon content of 99% by mass.
The material for a negative electrode of a lithium secondary battery according to any one of claims 1 to 4, wherein the specific surface area by the BET method is 5 m 2 / g or less. 【請求項６】 金属と炭素の溶融状態の冷却過程に析出
した炭素を、炭素含有量が９０質量％以上になるまで高
純度化処理を行った後に、インペラーミル、ジェットミ
ル、レイモンドミルまたはボールミルより選ばれた粉砕
機を用いた粉砕と空気分級を行うことにより得られた黒
鉛と、炭素質バインダーとを捏合し、該捏合物を７００
〜１５００℃で炭化及び／または２４００〜３０００℃
で黒鉛化することを特徴とするリチウム二次電池負極用
材料の製造方法。6. An impeller mill, a jet mill, a Raymond mill or a ball mill, after subjecting carbon precipitated in a cooling process in a molten state of metal and carbon to a high purification treatment until the carbon content becomes 90% by mass or more. The graphite obtained by performing pulverization using a pulverizer selected from the above and air classification is kneaded with a carbonaceous binder, and the kneaded product is 700
Carbonized at ~ 1500C and / or 2400-3000C
A method for producing a material for a negative electrode of a lithium secondary battery, comprising: 【請求項７】 前記金属は、鉄、ニッケル、シリコンお
よびコバルトからなる群より選択される１種または２種
以上の金属であることを特徴とする請求項６記載のリチ
ウム二次電池負極用材料の製造方法。7. The material for a negative electrode of a lithium secondary battery according to claim 6, wherein the metal is one or more metals selected from the group consisting of iron, nickel, silicon and cobalt. Manufacturing method. 【請求項８】 金属と炭素の溶融状態が、製鉄プロセス
の溶融銑鉄における鉄と炭素の溶融状態であることを特
徴とする請求項６記載のリチウム二次電池負極用材料の
製造方法。8. The method for producing a negative electrode material for a lithium secondary battery according to claim 6, wherein the molten state of the metal and carbon is the molten state of iron and carbon in the molten pig iron in the iron making process. 【請求項９】 前記黒鉛の平均粒径が３μｍ以上３０μ
ｍ以下であることを特徴とする請求項６〜８の何れか１
項に記載のリチウム二次電池負極用材料の製造方法。9. The graphite having an average particle size of 3 μm or more and 30 μm or more.
m is equal to or less than m.
13. The method for producing a material for a negative electrode of a lithium secondary battery according to item 10. 【請求項１０】 前記黒鉛と前記炭素質バインダーを、
該炭素質バインダーの軟化点以上の温度に加熱しながら
撹拌、捏合することを特徴とする請求項６〜９の何れか
１項に記載のリチウム二次電池負極用材料の製造方法。10. The graphite and the carbonaceous binder,
The method for producing a negative electrode material for a lithium secondary battery according to any one of claims 6 to 9, wherein the carbonaceous binder is stirred and kneaded while being heated to a temperature equal to or higher than the softening point of the carbonaceous binder. 【請求項１１】 前記黒鉛と前記炭素質バインダーの捏
合割合が、黒鉛１００質量部に対して、炭素質バインダ
ーが１０〜７０質量部であることを特徴とする請求項６
〜１０の何れか１項に記載のリチウム二次電池負極用材
料の製造方法。11. The kneading ratio of the graphite and the carbonaceous binder is 10 to 70 parts by mass of the carbonaceous binder based on 100 parts by mass of the graphite.
11. The method for producing a material for a negative electrode of a lithium secondary battery according to any one of items 10 to 10. 【請求項１２】 正極活物質と、請求項１〜５の何れか
１項に記載のリチウム二次電池負極用材料を含んでなる
負極活物質と、非水系電解質とを含んでなるリチウム二
次電池。12. A lithium secondary battery comprising a positive electrode active material, a negative electrode active material comprising the negative electrode material for a lithium secondary battery according to claim 1, and a non-aqueous electrolyte. battery.
JP2000176797A 2000-06-13 2000-06-13 Negative electrode material for lithium secondary battery, its manufacturing method, and lithium secondary battery Withdrawn JP2001357849A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2000176797A JP2001357849A (en) 2000-06-13 2000-06-13 Negative electrode material for lithium secondary battery, its manufacturing method, and lithium secondary battery

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2000176797A JP2001357849A (en) 2000-06-13 2000-06-13 Negative electrode material for lithium secondary battery, its manufacturing method, and lithium secondary battery

Publications (1)

Publication Number Publication Date
JP2001357849A true JP2001357849A (en) 2001-12-26

Family

ID=18678480

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2000176797A Withdrawn JP2001357849A (en) 2000-06-13 2000-06-13 Negative electrode material for lithium secondary battery, its manufacturing method, and lithium secondary battery

Country Status (1)

Country Link
JP (1) JP2001357849A (en)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002071515A1 (en) * 2001-03-06 2002-09-12 Nippon Steel Chemical Co., Ltd. Graphite material for negative pole of lithium secondary battery, method of manufacturing the graphite material, and lithium secondary battery
US7052803B2 (en) 2002-07-31 2006-05-30 Matsushita Electric Industrial Co., Ltd. Lithium rechargeable battery
JP2006172804A (en) * 2004-12-14 2006-06-29 Dainippon Printing Co Ltd Active material, coating composition containing the same, electrode plate, and nonaqueous electrolytic solution secondary battery
JP2007191369A (en) * 2006-01-20 2007-08-02 Jfe Chemical Corp Method for producing fine graphite particle
JP2015212228A (en) * 2008-10-27 2015-11-26 イメリス グラファイト アンド カーボン スイッツァランド リミティド Process for production and treatment of graphite powders
CN112133896A (en) * 2020-09-15 2020-12-25 捷威动力工业嘉兴有限公司 High-capacity graphite-silicon oxide composite material and preparation method and application thereof
CN115117355A (en) * 2022-08-24 2022-09-27 湖南金阳烯碳新材料股份有限公司 Preparation method and application of negative electrode material for secondary battery

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002071515A1 (en) * 2001-03-06 2002-09-12 Nippon Steel Chemical Co., Ltd. Graphite material for negative pole of lithium secondary battery, method of manufacturing the graphite material, and lithium secondary battery
US7141229B2 (en) 2001-03-06 2006-11-28 Nippon Steel Chemical Co., Ltd. Graphite material for negative pole of lithium secondary battery, method of manufacturing the graphite material, and lithium secondary battery
US7052803B2 (en) 2002-07-31 2006-05-30 Matsushita Electric Industrial Co., Ltd. Lithium rechargeable battery
JP2006172804A (en) * 2004-12-14 2006-06-29 Dainippon Printing Co Ltd Active material, coating composition containing the same, electrode plate, and nonaqueous electrolytic solution secondary battery
JP2007191369A (en) * 2006-01-20 2007-08-02 Jfe Chemical Corp Method for producing fine graphite particle
JP4707570B2 (en) * 2006-01-20 2011-06-22 Ｊｆｅケミカル株式会社 Method for producing fine graphite particles
JP2015212228A (en) * 2008-10-27 2015-11-26 イメリス グラファイト アンド カーボン スイッツァランド リミティド Process for production and treatment of graphite powders
CN112133896A (en) * 2020-09-15 2020-12-25 捷威动力工业嘉兴有限公司 High-capacity graphite-silicon oxide composite material and preparation method and application thereof
CN115117355A (en) * 2022-08-24 2022-09-27 湖南金阳烯碳新材料股份有限公司 Preparation method and application of negative electrode material for secondary battery

Similar Documents

Publication Publication Date Title
JP4945029B2 (en) Material for negative electrode of lithium secondary battery, method for producing the same, and lithium secondary battery
US10978733B2 (en) Carbon-coated silicon particles for lithium ion batteries
US9096473B2 (en) Coated carbonaceous particles particularly useful as electrode materials in electrical storage cells, and method of making the same
CN110870115B (en) Negative electrode active material, negative electrode comprising same, and lithium secondary battery
US7052803B2 (en) Lithium rechargeable battery
EP1681738B1 (en) Nonaqueous electrolyte secondary battery negative electrode material, production method therefor, nonaqueous electrolyte secondary battery negative electrode comprising the negative electrode material and nonaqueous electrolyte secondary battery comprising the negative electrode
JP4403327B2 (en) Graphite powder for negative electrode of lithium ion secondary battery, method for producing the same, and lithium ion secondary battery
KR102128796B1 (en) Silicon Oxide, Making Method, Negative Electrode, Lithium Ion Secondary Battery, and Electrochemical Capacitor
JPH10326611A (en) Carbon material for negative electrode of lithium secondary battery
JPH09147860A (en) Negative electrode material for lithium ion secondary battery
JPH0831422A (en) Carbon material for negative electrode of lithium secondary battery and manufacture thereof
JP2018006270A (en) Graphite carbon material for lithium ion secondary battery negative electrode, method for manufacturing the same, and negative electrode or battery arranged by use thereof
JP2000182617A (en) Carbon material for lithium secondary battery electrode and its manufacture, and lithium secondary battery
JP2001357849A (en) Negative electrode material for lithium secondary battery, its manufacturing method, and lithium secondary battery
JP2000086343A (en) Carbon composite material and its production
JP2013258135A (en) Silicon oxide particle, manufacturing method thereof, lithium ion secondary battery, and electrochemical capacitor
KR20150107674A (en) Negative electrode active material for lithium ion secondary battery, negative electrode for lithium ion secondary battery using the same, and lithium ion secondary battery
JP2004059386A (en) Production method for carbon-coated graphite particle, carbon-coated graphite particle, cathode for lithium-ion secondary battery, and lithium-ion secondary battery
JPH10223223A (en) Anode material for lithium secondary battery and manufacture thereof
JPH10149830A (en) Carbon material for nonaqueous solvent secondary battery negative electrode
JP2000012021A (en) Carbon material for lithium secondary battery negative electrode
JP2000012020A (en) Carbon material for lithium secondary battery negative electrode
JP2001216964A (en) Graphite for lithium secondary battery negative electrode and its manufacturing method as well as lithium secondary battery
JP2001216963A (en) Graphite for lithium secondary battery negative electrode and its manufacturing method as well as lithium secondary battery
JP3725662B2 (en) High graphitized carbon powder for negative electrode of lithium secondary battery

Legal Events

Date Code Title Description
A300 Withdrawal of application because of no request for examination

Free format text: JAPANESE INTERMEDIATE CODE: A300

Effective date: 20070904