JP2004253379A - Negative electrode material and negative electrode for lithium-ion secondary battery, and lithium-ion secondary battery - Google Patents

Negative electrode material and negative electrode for lithium-ion secondary battery, and lithium-ion secondary battery Download PDF

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JP2004253379A
JP2004253379A JP2004022081A JP2004022081A JP2004253379A JP 2004253379 A JP2004253379 A JP 2004253379A JP 2004022081 A JP2004022081 A JP 2004022081A JP 2004022081 A JP2004022081 A JP 2004022081A JP 2004253379 A JP2004253379 A JP 2004253379A
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negative electrode
carbon material
graphite
secondary battery
ion secondary
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JP4104561B2 (en
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Makiko Ijiri
真樹子 井尻
Kunihiko Eguchi
邦彦 江口
Hitomi Hatano
仁美 羽多野
Yoichi Tajima
洋一 田島
Yoshinori Takagi
嘉則 高木
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JFE Chemical Corp
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a negative electrode material and a negative electrode for a lithium-ion secondary battery that have excellent cycle characteristics and rate characteristics even at high density and even when an aqueous binder is used, and a lithium-ion secondary battery using the same having excellent cycle characteristics and rate characteristics. <P>SOLUTION: This negative electrode material is for a lithium-ion secondary battery which contains a hydrophilized graphite particle and a compound graphite carbon material that has a coating of a low crystalline carbon material and has an R value of 0.1 or more and less than 0.3 measured in Raman spectrometry, and a negative electrode using the negative electrode material and a lithium-ion secondary battery using the negative electrode are provided. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

本発明は、初期充放電効率が高い上、特に水系結着剤を用いて負極を作製した場合であっても、高速充電可能なリチウムイオン二次電池を得ることができるリチウムイオン二次電池用負極材料、該負極材料からなる負極および該負極を用いたリチウムイオン二次電池に関する。   The present invention has a high initial charge / discharge efficiency, and particularly for a lithium ion secondary battery capable of obtaining a lithium ion secondary battery capable of high-speed charging, even when a negative electrode is produced using an aqueous binder. The present invention relates to a negative electrode material, a negative electrode made of the negative electrode material, and a lithium ion secondary battery using the negative electrode.

近年、電子機器の小型化あるいは高性能化に伴い、電池の高エネルギー密度化に対する要望はますます高まっている。このような状況のなか、エネルギー密度が高く、高電圧化が可能な電池として、リチウムイオン二次電池が注目されている。このリチウムイオン二次電池の負極材料としては、充放電特性に優れ、高い放電容量と電位平坦性とを示す黒鉛が主流となっている（例えば、特許文献１）。負極材料として使用される黒鉛（黒鉛質材料）としては、天然黒鉛、人造黒鉛などの黒鉛粒子、さらにはタール、ピッチを原料としたメソフェーズピッチ、例えば、メソフェーズ小球体などを熱処理して得られるメソフェーズ系黒鉛質粒子が挙げられる。   2. Description of the Related Art In recent years, with the miniaturization or high performance of electronic devices, demands for higher energy density of batteries have been increasing. In such a situation, a lithium ion secondary battery has attracted attention as a battery having a high energy density and capable of increasing the voltage. As a negative electrode material of this lithium ion secondary battery, graphite which has excellent charge / discharge characteristics and exhibits high discharge capacity and potential flatness is mainly used (for example, Patent Document 1). Graphite (graphitic material) used as a negative electrode material includes graphite particles such as natural graphite and artificial graphite, as well as mesophase pitch obtained from tar and pitch as raw materials, for example, mesophase obtained by heat treatment of mesophase small spheres. Series graphite particles.

また、天然黒鉛または人造黒鉛の表面を有機化合物で被覆し、焼成し、黒鉛化して得た黒鉛質炭素材料は、リチウムイオン二次電池の負極材料としての高温特性、充放電効率、サイクル効率が良好なことが知られている（例えば、特許文献２〜４など）。   Graphite carbon material obtained by coating the surface of natural graphite or artificial graphite with an organic compound, calcining and graphitizing has high temperature characteristics, charge / discharge efficiency, and cycle efficiency as a negative electrode material for lithium ion secondary batteries. It is known to be good (for example, Patent Documents 2 to 4 and the like).

負極は、負極材料、負極材料同士および負極材料と集電材とを結着させるための結着剤（バインダー樹脂）と集電材から作製される。具体的には、通常、負極材料と結着剤とから負極合剤ペーストを調製し、ついで、該ペーストを銅箔などの集電材上に塗布してプレスし、負極が作製される。   The negative electrode is made of a negative electrode material, a negative electrode material, a binder (binder resin) for binding the negative electrode material and the current collector, and a current collector. Specifically, usually, a negative electrode mixture paste is prepared from a negative electrode material and a binder, and then the paste is applied on a current collector such as a copper foil and pressed to produce a negative electrode.

特公昭６２−２３４３３号公報JP-B-62-23433 特開平５−３０７０５９号公報JP-A-5-307059 特開平１０−３３４９１６号公報JP-A-10-334916 特開平１１−３４３１０８号公報JP-A-11-343108

負極材料としての天然黒鉛は、放電容量が大きい反面、りん片状という形状に起因して、負極を作製した際に、配向しやすく、サイクル特性（充放電を繰返したときの放電容量と初回の放電容量との比率）およびレート特性（急速充放電効率）が低下するという問題があった。   Natural graphite as a negative electrode material has a large discharge capacity, but because of its scaly shape, it is easily oriented when a negative electrode is manufactured, and its cycle characteristics (discharge capacity after repeated charge / discharge and initial There is a problem that the ratio to the discharge capacity) and the rate characteristics (rapid charge / discharge efficiency) are reduced.

一方、メソフェーズピッチを熱処理して得られる黒鉛質粒子、特にメソフェーズ小球体の黒鉛質粒子は、球状または球状に近い形状を有し、負極作製時にランダムに積層することから良好なサイクル特性およびレート特性を有するが、負極を作製する際の結着剤の種類によってはこれらの性能を充分に引き出せない場合がある。例えば、結着剤の分散媒が有機溶媒の場合は、負極材料の性能を充分に発揮することができるが、水系溶媒の場合は、充電速度などの電池特性が低下することがある。近年、環境面、安全面などの観点から、水系溶媒、したがって水系結着剤の使用が望まれている状況に鑑み、水系結着剤を使用する場合であっても、黒鉛質粒子に負極材料としての性能を充分に発揮させ得る技術の出現が望まれている。   On the other hand, the graphitic particles obtained by heat-treating the mesophase pitch, particularly the graphitic particles of the mesophase spheroids, have a spherical or nearly spherical shape, and have good cycle characteristics and rate characteristics because they are randomly laminated during negative electrode production. However, depending on the type of the binder used in producing the negative electrode, these properties may not be sufficiently exhibited. For example, when the dispersion medium of the binder is an organic solvent, the performance of the negative electrode material can be sufficiently exhibited. However, when the dispersion medium is an aqueous solvent, the battery characteristics such as the charging rate may be deteriorated. In recent years, from the viewpoints of environment, safety, etc., in view of the situation in which the use of an aqueous solvent, and therefore an aqueous binder is desired, even when an aqueous binder is used, the graphite particles can be used as a negative electrode material. There is a demand for the emergence of a technology capable of fully exhibiting the performance of the present invention.

また、天然黒鉛、人造黒鉛の表面を炭素材料で完全に被覆する場合は、被覆材を多量に使用する必要があり、そうなると被覆された黒鉛質炭素材料の融着が増大する傾向がある。また、その後の熱処理温度によっては、充放電容量の低下が懸念される。また、リチウムイオン二次電池の高容量化には、負極の体積あたりの充放電容量を増大させることが特に有効である。しかし、そのために、被覆された黒鉛の高密度化を図って、極板のプレス圧力を高めたり、圧延を数回繰返すと、被覆材と芯材である黒鉛との界面が脆弱であることが原因で、割れることがある。その際、新たに生成した界面は、被覆されておらず、活性があるために、電解液との反応性が高く、充放電効率を低下させることがあり、高密度化に対応できないという欠点がある。
また黒鉛が高結晶性である場合には、高密度化により、配向し、充電特性、放電特性が低下する問題も抱えている。 When the surface of natural graphite or artificial graphite is completely covered with a carbon material, it is necessary to use a large amount of the coating material, and if so, the fusion of the coated graphitic carbon material tends to increase. In addition, depending on the subsequent heat treatment temperature, there is a concern that the charge / discharge capacity may decrease. To increase the capacity of the lithium ion secondary battery, it is particularly effective to increase the charge / discharge capacity per volume of the negative electrode. However, if the density of the coated graphite is increased and the pressing pressure of the electrode plate is increased or rolling is repeated several times, the interface between the coating material and the core graphite may be weak. It may be broken due to the cause. At this time, the newly formed interface is not coated and has activity, so it has a high reactivity with the electrolyte solution, which may lower the charge / discharge efficiency, and cannot cope with high density. is there.
In addition, when graphite has high crystallinity, there is also a problem that orientation is increased and charge characteristics and discharge characteristics are reduced due to high density.

したがって、本発明は、良好なサイクル特性とレート特性を有するリチウムイオン二次電池用の負極材料と負極、それを用いた、良好なサイクル特性とレート特性を有するリチウムイオン二次電池を提供することを目的とする。   Accordingly, the present invention provides a negative electrode material and a negative electrode for a lithium ion secondary battery having good cycle characteristics and rate characteristics, and a lithium ion secondary battery having good cycle characteristics and rate characteristics using the same. With the goal.

本発明は、前記のような黒鉛系リチウムイオン二次電池用負極材料の課題を解決するものであり、親水化された黒鉛質粒子Ａと、黒鉛Ｂの少なくとも一部に、低い結晶性の炭素材料Ｃの被覆を有する複合黒鉛質炭素材料Ｄとを含有し、前記複合黒鉛質炭素材料Ｄのアルゴンレーザーを用いたラマン分光法により測定された１３６０cm-1ピーク強度（ＩＤ）と１５８０cm-1ピーク強度（ＩＧ）の比ＩＤ／ＩＧが０．１以上０．３未満であることを特徴とするリチウムイオン二次電池用負極材料である。 The present invention solves the above-described problem of the graphite-based negative electrode material for a lithium ion secondary battery, and includes a graphitized hydrophilic particle A and at least a part of graphite B having low crystalline carbon. containing composite graphitic carbon material D having a coating material C, the composite graphitic carbon material argon laser to 1360 cm -1 peak intensity measured by Raman spectroscopy using the D and (ID) 1580 cm -1 peak A negative electrode material for a lithium ion secondary battery, wherein the strength (IG) ratio ID / IG is 0.1 or more and less than 0.3.

本発明のリチウムイオン二次電池用負極材料は、前記親水化された黒鉛質粒子Ａが、メソフェーズ小球体またはその粉砕物を黒鉛化したのち、メカノケミカル処理により親水化してなる黒鉛質粒子Ａであることが好ましい。   The negative electrode material for a lithium ion secondary battery according to the present invention is a graphitic particle A obtained by graphitizing a mesophase microsphere or a pulverized product thereof, and then hydrophilizing by mechanochemical treatment. Preferably, there is.

本発明のリチウムイオン二次電池用負極材料は、前記複合黒鉛質炭素材料Ｄが、黒鉛Ｂに有機化合物Ｇを付着および／または含浸させた後、９００℃以上の温度で熱処理して得られた炭素材料Ｃの被覆を有する複合黒鉛質炭素材料Ｄであることが好ましい。   The negative electrode material for a lithium ion secondary battery of the present invention was obtained by applying the organic compound G to and / or impregnating the graphite B with the composite graphitic carbon material D and then performing a heat treatment at a temperature of 900 ° C. or more. The composite graphite carbon material D having a carbon material C coating is preferable.

本発明のリチウムイオン二次電池用負極材料は、前記複合黒鉛質炭素材料Ｄが、黒鉛Ｂに有機化合物Ｇを付着および／または含浸させた後、９００℃以上２８００℃未満の温度で熱処理して得られた炭素材料Ｃの被覆を有する複合黒鉛質炭素材料Ｄであることが好ましい。   In the negative electrode material for a lithium ion secondary battery of the present invention, the composite graphitic carbon material D is prepared by adhering and / or impregnating the graphite B with the organic compound G, and then performing a heat treatment at a temperature of 900 ° C. or more and less than 2800 ° C. The composite graphite material D having a coating of the obtained carbon material C is preferable.

本発明のリチウムイオン二次電池用負極材料は、前記複合黒鉛質炭素材料Ｄが、黒鉛Ｂに難黒鉛化性炭素前駆体を付着および／または含浸させた後、２８００℃以上の温度で熱処理して得られた炭素材料Ｃの被覆を有する複合黒鉛質炭素材料Ｄであることが好ましい。   In the negative electrode material for a lithium ion secondary battery of the present invention, the composite graphitic carbon material D is subjected to a heat treatment at a temperature of 2800 ° C. or more after the graphite B is attached and / or impregnated with the non-graphitizable carbon precursor. It is preferably a composite graphitic carbon material D having a coating of the carbon material C obtained as described above.

本発明のリチウムイオン二次電池用負極材料は、前記いずれかの複合黒鉛質炭素材料Ｄの平均粒径が１〜３０μｍであることが好ましい。   In the negative electrode material for a lithium ion secondary battery of the present invention, it is preferable that any of the composite graphite carbon materials D has an average particle size of 1 to 30 μm.

本発明のリチウムイオン二次電池用負極材料となる前記複合黒鉛質炭素材料Ｄの、黒鉛Ｂに付着および／または含浸させる有機化合物Ｇについては、本発明の範囲で熱処理を行う際に、残留炭素分を有する有機化合物であれば、いかなるものでも構わないが、熱硬化性樹脂、熱可塑性樹脂またはそれらの混合物など、石炭系または石油系の重質油、または石炭系または石油系のピッチであることが好ましい。   Regarding the organic compound G to be attached and / or impregnated to the graphite B of the composite graphitic carbon material D serving as the negative electrode material for a lithium ion secondary battery of the present invention, the residual carbon during the heat treatment within the scope of the present invention. Any organic compound may be used, as long as it is a thermosetting resin, a thermoplastic resin or a mixture thereof, such as a coal-based or petroleum-based heavy oil, or a coal-based or petroleum-based pitch. Is preferred.

本発明は、前記いずれかのリチウムイオン二次電池用負極材料からなることを特徴とするリチウムイオン二次電池用負極である。   The present invention provides a negative electrode for a lithium ion secondary battery, comprising the negative electrode material for a lithium ion secondary battery described above.

本発明は、前記のリチウムイオン二次電池用負極を用いることを特徴とするリチウムイオン二次電池である。   The present invention is a lithium ion secondary battery using the above-described negative electrode for a lithium ion secondary battery.

本発明の負極材料は、放電容量、初期充放電効率と急速充放電効率が高く、サイクル特性にも優れ、特に水系結着剤を用い、高密度化された負極を作製したときも、良好な充放電特性を示す。そのため、本発明のリチウムイオン二次電池は、近年の電池の高エネルギー密度化に対する要望を満たし、搭載する機器の小型化および高性能化に有効である。   The negative electrode material of the present invention has a high discharge capacity, high initial charge / discharge efficiency and rapid charge / discharge efficiency, excellent cycle characteristics, especially when an aqueous binder is used, and a high-density negative electrode is produced. It shows charge and discharge characteristics. Therefore, the lithium ion secondary battery of the present invention satisfies the recent demand for a higher energy density of the battery, and is effective for downsizing and higher performance of a mounted device.

以下、本発明を具体的に説明する。
本発明においては、親水化された黒鉛質粒子Ａと、黒鉛Ｂの少なくとも一部に、低い結晶性の炭素材料Ｃの被覆を有し、複合黒鉛質炭素材料Ｄのアルゴンレーザーを用いたラマン分光法により測定された１３６０cm-1ピーク強度（ＩＤ）と１５８０cm-1ピーク強度（ＩＧ）の比ＩＤ／ＩＧが０．１以上０．３未満である複合黒鉛質炭素材料Ｄとを含有させてリチウムイオン二次電池用負極材料を調製する。 Hereinafter, the present invention will be described specifically.
In the present invention, Raman spectroscopy of a composite graphitic carbon material D using an argon laser has a coating of a low crystalline carbon material C on at least a part of the graphite particles A that have been hydrophilized, and at least a portion of the graphite B. Containing a composite graphitic carbon material D in which the ratio ID / IG of the 1360 cm -1 peak intensity (ID) to the 1580 cm -1 peak intensity (IG) measured by the method is 0.1 or more and less than 0.3. A negative electrode material for an ion secondary battery is prepared.

（親水化された黒鉛質粒子Ａ）
親水化された黒鉛質粒子Ａとは、黒鉛質粒子に、親水性を付与するための処理が施された黒鉛質粒子のことを言う。親水化された黒鉛質粒子Ａを用いることにより、後述する負極合剤中において、結着剤（特に水系結着剤）が親水化された黒鉛質粒子Ａの周囲に均一に分散し、負極合剤全体の導電性が大きく改善され、充電特性および放電特性が向上する。黒鉛質粒子の親水性は、黒鉛質粒子と水との接触角の測定、または黒鉛質粒子への水の浸透速度、浸透量の測定などにより知ることができる。本発明においては、２５℃において、黒鉛質粒子１５ｇを底部（内径３６ｍｍ）が金網およびろ紙からなる円筒容器に充填し、１８０回タッピングを繰返した後、該容器の底部を水面に接触させ、水の浸透量を測定して親水化度とした。例えば、水の浸透時間が３０sec の場合の浸透量が０．５ｇ以上のもの、好ましくは０．８ｇ以上のもの、より好ましくは１．０ｇ以上のものを親水性が付与されたものとする。
親水化は、黒鉛質粒子に水溶性樹脂を付着する方法、黒鉛質粒子を気相中または液相中で酸化する方法などの通常の親水化手段によるが、特に好ましいのは、黒鉛質粒子Ｅをメカノケミカル処理して親水化した場合である。 (Hydrophilic graphitic particles A)
The hydrophilized graphitic particles A refer to graphitic particles that have been subjected to a treatment for imparting hydrophilicity to the graphitic particles. By using the hydrophilized graphitic particles A, the binder (particularly, an aqueous binder) is uniformly dispersed around the hydrophilized graphitic particles A in the negative electrode mixture described below, and The conductivity of the entire agent is greatly improved, and the charging characteristics and discharging characteristics are improved. The hydrophilicity of the graphitic particles can be known by measuring the contact angle between the graphitic particles and water, or measuring the penetration rate and amount of water into the graphitic particles. In the present invention, at 25 ° C., 15 g of graphitic particles are filled in a cylindrical container having a bottom portion (inner diameter of 36 mm) made of a wire mesh and filter paper, and after tapping is repeated 180 times, the bottom portion of the container is brought into contact with the water surface, Was measured as the degree of hydrophilicity. For example, when the water permeation time is 30 sec, the permeation amount is 0.5 g or more, preferably 0.8 g or more, and more preferably 1.0 g or more, to which the hydrophilicity is imparted.
The hydrophilization is carried out by a general hydrophilization means such as a method of attaching a water-soluble resin to the graphite particles and a method of oxidizing the graphite particles in a gas phase or a liquid phase. Is hydrophilized by mechanochemical treatment.

メカノケミカル処理される黒鉛質粒子Ｅは、結晶性（黒鉛化度）の高い炭素材料である。例えば、石炭系のタール、ピッチを加熱して得られるメソフェーズ焼成炭素（バルクメソフェーズ）、メソフェーズ小球体、コークス類（生コークス、グリーンコークス、ピッチコークス、ニードルコークス、石油コークスなど）を２５００℃以上の温度で熱処理（黒鉛化）したもの、または石油系タール、ピッチを熱処理（黒鉛化）したものが例示される。メカノケミカル処理される黒鉛質粒子Ｅは、上記例示した各黒鉛質粒子Ｅの組合わせであってもよい。なお、上記熱処理は、メソフェーズピッチ（バルクメソフェーズ、メソフェーズ小球体）を炭素化する工程、黒鉛化する工程などの加熱工程の全てを含む。   The graphitic particles E to be subjected to the mechanochemical treatment are carbon materials having high crystallinity (degree of graphitization). For example, coal-based tar, mesophase calcined carbon (bulk mesophase) obtained by heating pitch, mesophase spherules, cokes (raw coke, green coke, pitch coke, needle coke, petroleum coke, etc.) at 2500 ° C. or higher Heat treated (graphitized) at a temperature, or petroleum tar and pitch heat treated (graphitized) are exemplified. The graphitic particles E to be subjected to the mechanochemical treatment may be a combination of the respective graphitic particles E exemplified above. The heat treatment includes all heating steps such as a step of carbonizing mesophase pitch (bulk mesophase and mesophase small spheres) and a step of graphitizing.

また、メカノケミカル処理される黒鉛質粒子Ｅとして人造黒鉛、天然黒鉛なども例示することができる。天然黒鉛は、元来ある程度の表面親水性を有するが、その程度の親水性では、本発明が期待するサイクル特性およびレート特性が得られない。
前記のうち、メカノケミカル処理される黒鉛質粒子Ｅとしては、電池特性上、メソフェーズ小球体の黒鉛質粒子が特に好ましい。 Examples of the graphite particles E to be subjected to mechanochemical treatment include artificial graphite and natural graphite. Natural graphite originally has a certain degree of surface hydrophilicity, but with such a degree of hydrophilicity, the cycle characteristics and rate characteristics expected by the present invention cannot be obtained.
Among the above, as the graphite particles E to be subjected to the mechanochemical treatment, mesophase small spherical graphite particles are particularly preferable from the viewpoint of battery characteristics.

メカノケミカル処理される黒鉛質粒子Ｅは、高い放電容量を得るために、特にＸ線回折における格子面間隔ｄ002 が０．３４ｎｍ未満、好ましくは０．３３７ｎｍ以下の結晶性の高い黒鉛質粒子であることが好ましい。格子面間隔ｄ002 はＸ線としてCuK α線を用い、高純度シリコンを標準物質に使用して黒鉛質粒子の（００２）回折ピークを測定し、そのピーク位置より算出する。算出方法は学振法（日本学術振興会第１７委員会が定めた測定法）に従うものであり、具体的には、「炭素繊維」（大谷杉郎、７３３−７４２頁（１９８６年３月）、近代編集社）などに記載された方法によって測定された値である。 In order to obtain a high discharge capacity, the graphite particles E to be subjected to the mechanochemical treatment are, in particular, highly crystalline graphite particles having a lattice spacing d 002 in X-ray diffraction of less than 0.34 nm, preferably 0.337 nm or less. Preferably, there is. The lattice spacing d 002 is calculated from the (002) diffraction peak of the graphitic particles using CuK α-rays as X-rays, using high-purity silicon as a standard substance, and measuring the (002) diffraction peak. The calculation method is in accordance with the Japan Society for the Promotion of Science (measurement method determined by the 17th Committee of the Japan Society for the Promotion of Science), and specifically, “Carbon Fiber” (Sugio Otani, pp. 733-742 (March 1986)) , Kindai Kogyosha) and the like.

メカノケミカル処理される黒鉛質粒子Ｅの平均粒径は特に問わないが、通常１〜１００μｍ、好ましくは５〜４０μｍである。負極の厚みなどによって調整される。平均粒径はレーザー回折式粒度分布計により測定した粒度分布の累積度数が体積百分率で５０％となる粒径である。また黒鉛質粒子Ｅの比表面積が大きすぎると不可逆容量の増大や電池の安全性の低下を招くため、比表面積は好ましくは２０m2/g以下であり、より好ましくは５m2/ ｇ以下０．１m2/ ｇ以上である。比表面積は窒素ガス吸着ＢＥＴ法により測定される。また、黒鉛質粒子Ｅの真比重は２．２以上であることが好ましい。真比重はブタノールを溶媒に用いた液相置換法により測定される。
メカノケミカル処理される黒鉛質粒子Ｅの形態は特に限定されないが、球状、粒状、塊状、りん片状、繊維状などであることが好ましい。 The average particle size of the graphitic particles E to be subjected to the mechanochemical treatment is not particularly limited, but is usually 1 to 100 μm, preferably 5 to 40 μm. It is adjusted by the thickness of the negative electrode. The average particle size is a particle size at which the cumulative frequency of the particle size distribution measured by a laser diffraction type particle size distribution meter becomes 50% by volume percentage. If the specific surface area of the graphitic particles E is too large, the irreversible capacity will increase and the safety of the battery will decrease. Therefore, the specific surface area is preferably 20 m 2 / g or less, more preferably 5 m 2 / g or less. It is 1 m 2 / g or more. The specific surface area is measured by a nitrogen gas adsorption BET method. The true specific gravity of the graphite particles E is preferably 2.2 or more. The true specific gravity is measured by a liquid phase replacement method using butanol as a solvent.
The form of the graphitic particles E to be subjected to the mechanochemical treatment is not particularly limited, but is preferably spherical, granular, massive, scaly, fibrous, or the like.

メカノケミカル処理される黒鉛質粒子Ｅは、本発明の目的を損なわない範囲であれば、他の炭素材料（非晶質ハードカーボンなどを含む）、有機物、金属化合物との混合物、造粒物、被覆物、積層物であってもよい。また、液相、気相、固相における各種化学的処理、熱処理、酸化処理などを施したものであってもよい。   Graphite particles E to be subjected to mechanochemical treatment may be mixed with other carbon materials (including amorphous hard carbon), organic substances, metal compounds, granulated substances, or the like, as long as the object of the present invention is not impaired. It may be a coating or a laminate. In addition, it may have been subjected to various chemical treatments, heat treatment, oxidation treatment, and the like in a liquid phase, a gas phase, and a solid phase.

（硬質微粒子Ｆ）
前記黒鉛質粒子Ｅに後述するメカノケミカル処理を施す際に、硬質微粒子Ｆの共存下に該処理を行うことが好ましい。
該硬質微粒子Ｆは、該黒鉛質粒子Ｅの平均粒径よりも小さい平均粒径を有し、かつ該黒鉛質粒子Ｅよりも硬いものであればよく、これら以外の条件は特に制限されない。硬質微粒子Ｆが凝集物である場合には、その一次粒子の平均粒径が黒鉛質粒子Ｅの平均粒径よりも小さい凝集物であればよい。硬質微粒子Ｆの平均粒径が１ｎｍより大きければ、黒鉛質粒子Ｅに親水性を付与することができる。平均粒径が１００ｎｍ以下であれば、黒鉛質粒子Ｅ同士の接触を妨げず、充放電特性に悪影響を及ぼさない。 (Hard fine particles F)
When performing the mechanochemical treatment to be described later on the graphite particles E, it is preferable to perform the treatment in the presence of the hard fine particles F.
The hard fine particles F may have an average particle size smaller than the average particle size of the graphite particles E and be harder than the graphite particles E, and other conditions are not particularly limited. When the hard fine particles F are agglomerates, it is sufficient that the average particle diameter of the primary particles is smaller than the average particle diameter of the graphitic particles E. If the average particle diameter of the hard fine particles F is larger than 1 nm, hydrophilicity can be imparted to the graphite particles E. When the average particle size is 100 nm or less, the contact between the graphite particles E is not hindered, and the charge / discharge characteristics are not adversely affected.

硬質微粒子Ｆは導電性および充放電特性に寄与するものであっても、寄与しないものであっても差支えなく、金属、金属酸化物、金属窒化物、金属ホウ化物、金属炭化物などである。親水性を有する硬質微粒子Ｆが好ましく、特に、気相法によって製造された無水シリカ（気相シリカ）、酸化チタン、酸化アルミニウムなどの金属酸化物の微粒子が好適である。親水性を有する硬質微粒子Ｆを用いることにより、黒鉛質粒子Ｅへのメカノケミカル処理による親水性付与に加えて、一段と高い親水性を付与することができる。   The hard fine particles F may or may not contribute to conductivity and charge / discharge characteristics, and may be a metal, a metal oxide, a metal nitride, a metal boride, a metal carbide, or the like. Hard fine particles F having hydrophilicity are preferable, and fine particles of metal oxides such as anhydrous silica (gas phase silica), titanium oxide, and aluminum oxide produced by a gas phase method are particularly preferable. By using the hard fine particles F having hydrophilicity, in addition to imparting hydrophilicity to the graphitic particles E by mechanochemical treatment, higher hydrophilicity can be imparted.

黒鉛質粒子Ｅのメカノケミカル処理には、上記のような硬質微粒子Ｆを、通常、黒鉛質粒子Ｅに対し０．０１〜１０質量％の割合で使用する。メカノケミカル処理に使用された硬質微粒子Ｆは、その後作製される負極材料中に残存させる必要はないが、黒鉛質粒子Ｅに対し０．０１〜５質量％、好ましくは０．０１〜０．５質量％の割合で埋設、一体化することが好ましい。また硬質微粒子Ｆは、予め黒鉛質粒子Ｅとドライブレンドしてメカノケミカル処理に供してもよく、黒鉛質粒子Ｅのメカノケミカル処理中に添加してもよい。   For the mechanochemical treatment of the graphite particles E, the hard fine particles F as described above are usually used at a ratio of 0.01 to 10% by mass based on the graphite particles E. The hard fine particles F used in the mechanochemical treatment do not need to be left in the negative electrode material produced thereafter, but may be 0.01 to 5% by mass, preferably 0.01 to 0.5% by mass with respect to the graphite particles E. It is preferable to bury and integrate at a ratio of mass%. The hard fine particles F may be dry-blended with the graphite particles E in advance and subjected to the mechanochemical treatment, or may be added during the mechanochemical treatment of the graphite particles E.

（メカノケミカル処理）
メカノケミカル処理とは、黒鉛質粒子Ｅに圧縮力と剪断力を同時にかける処理を言う。剪断力や圧縮力は通常一般の攪拌力よりも大きいが、これら機械的応力は、黒鉛質粒子Ｅの表面にかけられることが好ましく、黒鉛質粒子Ｅの粒子骨格を破壊しないことが好ましい。黒鉛質粒子Ｅの粒子骨格が破壊されると、負極材料として使用したとき、不可逆容量の増大を招く傾向がある。剪断力や圧縮力は、一般的にはメカノケミカル処理による黒鉛質粒子Ｅの平均粒径の低下率を２０％以下に抑える程度であることが好ましい。 (Mechanochemical treatment)
The mechanochemical treatment is a treatment for simultaneously applying a compressive force and a shearing force to the graphite particles E. Although the shearing force and the compressive force are usually larger than the general stirring force, these mechanical stresses are preferably applied to the surface of the graphitic particles E, and it is preferable not to break the particle skeleton of the graphitic particles E. When the particle skeleton of the graphitic particles E is broken, the irreversible capacity tends to increase when used as a negative electrode material. Generally, it is preferable that the shearing force and the compressing force are such that the rate of decrease in the average particle size of the graphitic particles E by the mechanochemical treatment is suppressed to 20% or less.

メカノケミカル処理装置は、被処理物（黒鉛質粒子Ｅ、またはさらに硬質微粒子Ｆ）に圧縮力と剪断力を同時にかけることができる装置であれば、装置の種類、構造は特に限定されない。例えば加圧ニーダー、二本ロールなどの混練機、回転ボールミル、ハイブリダイゼーションシステム（（株）奈良機械製作所製）などの高速衝撃式乾式粉体複合化装置、メカノマイクロス（（株）奈良機械製作所製）、メカノフュージョンシステム（ホソカワミクロン（株）製）などの圧縮剪断式乾式粉体複合化装置などを使用することができる。   The type and structure of the mechanochemical treatment apparatus are not particularly limited as long as the apparatus can simultaneously apply a compressive force and a shearing force to an object to be treated (graphite particles E or hard fine particles F). For example, a kneader such as a pressure kneader or a two-roller, a rotary ball mill, a high-speed impact-type dry powder compounding apparatus such as a hybridization system (manufactured by Nara Machinery Co., Ltd.), Mechano Micros (Nara Machinery Co., Ltd.) And a mechanical shearing system (manufactured by Hosokawa Micron Co., Ltd.).

中でも回転速度差を利用して剪断力および圧縮力を同時にかける装置が好ましい。具体的には回転するドラム（回転ローター）と、該ドラムと回転速度の異なる内部部材（インナーピース）と、被処理物の循環機構（例えば循環用ブレード）とを有する装置（例えば図１(Ａ) 〜(Ｂ) に模式的機構を示すホソカワミクロン（株）製メカノフュージョンシステム）を用い、回転ドラムと内部部材との間に供給された被処理物に遠心力を付与しながら、内部部材により回転ドラムとの速度差に起因する圧縮力と剪断力とを同時に繰返しかけることによりメカノケミカル処理することが好ましい。
また固定ドラム（ステーター）と、高速回転する回転ローターの間に被処理物を通すことで固定ドラムと回転ローターとの速度差に起因する圧縮力と剪断力とを被処理物にかける装置（例えば図２に模式的機構を示す（株）奈良機械製作所製ハイブリダイゼーションシステム）も好ましい。 Above all, a device for simultaneously applying a shearing force and a compressive force by utilizing a rotational speed difference is preferable. Specifically, an apparatus (for example, FIG. 1A) having a rotating drum (rotating rotor), an internal member (inner piece) having a different rotation speed from the drum, and a circulating mechanism (for example, a circulating blade) for the object to be processed. ) To (B), using a meso-fusion system manufactured by Hosokawa Micron Co., Ltd.) and rotating the inner member while applying a centrifugal force to the workpiece supplied between the rotating drum and the inner member. It is preferable to perform a mechanochemical treatment by simultaneously and repeatedly applying a compressive force and a shear force caused by a speed difference from a drum.
Further, a device that applies a compressive force and a shearing force caused by a speed difference between the fixed drum and the rotating rotor to the object to be processed by passing the object between the fixed drum (stator) and the rotating rotor that rotates at a high speed (for example, A hybridization system (Nara Machinery Co., Ltd.) whose schematic structure is shown in FIG. 2 is also preferable.

メカノケミカル処理の条件は、使用する装置によっても異なり一概には言えないが、例えば、図１(Ａ) 〜(Ｂ) に示すような回転ドラム１１と内部部材（インナーピース）１２を備えた装置を用いる場合には、被処理物１３を回転ドラム１１に供給し、回転ドラム１１と内部部材１２との周速度差が５〜５０m/sec 、両者間の距離が１〜１００ｍｍ、処理時間が３〜９０min の条件で操業するのが好ましい。被処理物１３は該装置内の循環機構１４により循環され、メカノケミカル処理され、排出機構１５から排出される。
また図２に示すような固定ドラム２１とブレード２６を有する高速回転ローター２２を備えた装置を用いる場合には、被処理物２３を循環機構２４に供給し、固定ドラム２１と回転ローター２２との周速度差が１０〜１００m/sec 、処理時間が３０sec 〜１０min の条件で操業するのが好ましい。被処理物２３は該装置内の循環機構２４により循環され、メカノケミカル処理され、排出機構２５から排出される。なお、該装置にはステーター２７とジャケット２８が敷設されている。 The conditions of the mechanochemical treatment are different depending on the equipment used and cannot be said unconditionally. For example, an apparatus having a rotating drum 11 and an inner member (inner piece) 12 as shown in FIGS. Is used, the workpiece 13 is supplied to the rotating drum 11, the peripheral speed difference between the rotating drum 11 and the internal member 12 is 5 to 50 m / sec, the distance between the two is 1 to 100 mm, and the processing time is 3 It is preferred to operate under conditions of ~ 90 min. The object 13 is circulated by a circulation mechanism 14 in the apparatus, subjected to mechanochemical treatment, and discharged from a discharge mechanism 15.
In the case of using an apparatus provided with a high-speed rotating rotor 22 having a fixed drum 21 and a blade 26 as shown in FIG. 2, an object 23 to be processed is supplied to a circulating mechanism 24 so that the fixed drum 21 and the rotating rotor 22 It is preferable to operate under the conditions that the peripheral speed difference is 10 to 100 m / sec and the processing time is 30 sec to 10 min. The object 23 is circulated by a circulation mechanism 24 in the apparatus, subjected to mechanochemical treatment, and discharged from a discharge mechanism 25. The apparatus is provided with a stator 27 and a jacket 28.

黒鉛質体粒子Ｅのメカノケミカル処理前、処理中、処理後のいずれかにおいて、本発明が期待するサイクル特性とレート特性を損なわない範囲において、公知の導電性材料、イオン伝導性材料、界面活性剤、高分子化合物などの各種添加剤を添加することができる。   Prior to, during, or after the mechanochemical treatment of the graphitic particles E, a known conductive material, ion-conductive material, and surface active agent may be used as long as the cycle characteristics and rate characteristics expected by the present invention are not impaired. Various additives such as an agent and a polymer compound can be added.

メカノケミカル処理により、黒鉛質粒子Ｅに親水性が付与され、また、硬質微粒子Ｆを共存させた場合は、より親水性が大となるのに加え、表面の凸部が主に研磨され平滑化し、微細な粗さを有する表面に変化し、表面の滑り性がよくなる。また、表面の結晶性または配向性が低下するなどの表面特性が改善される結果、ラマン分光におけるＲ値が増大し、親水化された黒鉛質粒子Ａが得られる。表面改質効果が得られる機構は、必ずしも明確ではないが、メカノケミカル処理による圧縮下での剪断力により、黒鉛質粒子Ｅの表面が研磨されるためと推測される。特に硬質微粒子Ｆの共存下でのメカノケミカル処理では、黒鉛質粒子Ａの表面の研磨効果が高くなるとともに、硬質微粒子Ｆが黒鉛質粒子Ａの表面近傍に埋設され、一体化することも本発明の効果を助長する原因と考えられる。したがって、本発明においては、メカノケミカル処理、特に硬質微粒子Ｆを共存させるメカノケミカル処理によって親水化された黒鉛質粒子Ａの使用が特に好ましい。   The mechanochemical treatment imparts hydrophilicity to the graphitic particles E, and when the hard fine particles F coexist, in addition to the greater hydrophilicity, the convexities on the surface are mainly polished and smoothed. Changes to a surface having a fine roughness, and the surface has good slipperiness. In addition, as a result of improving the surface properties such as a decrease in the crystallinity or orientation of the surface, the R value in Raman spectroscopy increases, and the hydrophilic graphite particles A are obtained. The mechanism by which the surface modification effect is obtained is not necessarily clear, but it is presumed that the surface of the graphitic particles E is polished by the shearing force under compression by the mechanochemical treatment. In particular, in the mechanochemical treatment in the presence of the hard fine particles F, the polishing effect on the surface of the graphitic particles A is enhanced, and the hard fine particles F are buried near the surface of the graphite particles A to be integrated. It is considered to be a cause that promotes the effect of. Therefore, in the present invention, it is particularly preferable to use the graphitic particles A which have been hydrophilized by mechanochemical treatment, in particular, mechanochemical treatment in which the hard fine particles F coexist.

前記黒鉛質粒子Ａをリチウムイオン二次電池用負極材料として用いると、高い放電容量を維持しつつ、不可逆容量を低減する効果を奏する（すなわち、高い充放電効率を得る）ことができる。特に、負極は、後述するように、前記黒鉛質粒子Ａ、複合黒鉛質炭素材料Ｄと結着剤とから調製された負極合剤ペーストから作製されるが、このペースト調製時の結着剤が水溶性および／または水分散性結着剤（水系結着剤）であっても、結着剤の分散媒が有機溶媒系の場合と同等の充放電特性を得ることができる。   When the graphite particles A are used as a negative electrode material for a lithium ion secondary battery, an effect of reducing the irreversible capacity while maintaining a high discharge capacity can be obtained (that is, high charge / discharge efficiency can be obtained). In particular, the negative electrode is prepared from a negative electrode mixture paste prepared from the graphite particles A, the composite graphitic carbon material D, and a binder, as described below. Even with a water-soluble and / or water-dispersible binder (aqueous binder), the same charge / discharge characteristics as when the binder dispersion medium is an organic solvent can be obtained.

（低い結晶性の炭素材料Ｃの被覆を有する複合黒鉛質炭素材料Ｄ）
本発明の低い結晶性の炭素材料Ｃの被覆を有する複合黒鉛質炭素材料Ｄは、芯材が高結晶性の黒鉛Ｂであり、低い結晶性の炭素材料Ｃ（炭素質材料および／または黒鉛質材料）で芯材の少なくとも一部が被覆されている複合材料である。炭素材料Ｃは、該複合黒鉛質炭素材料Ｄの内部および／または表面に存在するものであり、内部および／または表面の少なくとも一部に存在すればよい。
低い結晶性とは、黒鉛Ｂの少なくとも一部を被覆する炭素材料Ｃの原料となる有機化合物Ｇを単独で、後述する熱処理をしたときに、Ｘ線回折における格子面間隔ｄ002 が０．３４ｎｍ以上を示す場合を意味する。被覆後の複合黒鉛質炭素材料ＤのＸ線回折においては、芯材の黒鉛Ｂと炭素材料Ｃとの結晶性の分離ができないだけではなく、被覆時と単独時では、異なる結晶性となることがあるため、Ｘ線回折での炭素材料Ｃの結晶性の解析は不適である。したがって、本発明において、低い結晶性とは、表面の状態をより分析しやすいラマン分光において、複合黒鉛質炭素材料ＤのＲ値が０．１以上、０．３未満を示す場合である。Ｒ値が０．１未満であると表面の結晶性が高く、本発明の効果を得るには至らない。一方、０．３以上であると表面の結晶性は十分に低いが、低すぎるため他の電池特性（初期充放電効率、急速放電効率）を劣化させる。
Ｒ値とは、アルゴンレーザーを用いたラマン分光法により測定したＤバンド１３６０cm-1ピーク強度ＩＤとＧバンド１５８０cm-1ピーク強度ＩＧの比ＩＤ／ＩＧである。 (Composite graphitic carbon material D having a coating of low crystalline carbon material C)
The composite graphitic carbon material D having the coating of the low crystalline carbon material C of the present invention has a core material of a high crystalline graphite B and a low crystalline carbon material C (carbonaceous material and / or graphite material). Material) is a composite material in which at least a part of the core material is coated. The carbon material C is present inside and / or on the surface of the composite graphitic carbon material D, and may be present on at least a part of the inside and / or the surface.
The low crystallinity means that when the organic compound G serving as a raw material of the carbon material C covering at least a part of the graphite B alone is subjected to a heat treatment described below, the lattice spacing d 002 in X-ray diffraction is 0.34 nm. This means the case shown above. In the X-ray diffraction of the composite graphitic carbon material D after coating, not only the crystallinity of the graphite B of the core material and the carbon material C cannot be separated, but also the crystallinity differs between when coated and when alone. Therefore, the analysis of the crystallinity of the carbon material C by X-ray diffraction is inappropriate. Therefore, in the present invention, low crystallinity refers to a case where the R value of the composite graphitic carbon material D is 0.1 or more and less than 0.3 in Raman spectroscopy in which the surface state can be more easily analyzed. If the R value is less than 0.1, the crystallinity of the surface is high, and the effect of the present invention cannot be obtained. On the other hand, if it is 0.3 or more, the crystallinity of the surface is sufficiently low, but it is too low to deteriorate other battery characteristics (initial charge / discharge efficiency, rapid discharge efficiency).
The R value is a ratio ID / IG of the D band 1360 cm -1 peak intensity ID and the G band 1580 cm -1 peak intensity IG measured by Raman spectroscopy using an argon laser.

前記複合黒鉛質炭素材料Ｄは、芯材の黒鉛Ｂに、有機化合物Ｇを付着および／または含浸させ、これを９００℃以上の温度で熱処理して得たものであることが好ましい。さらに好ましいのは、９００℃以上、２８００℃未満、特に好ましいのは１１５０℃以上、２３００℃未満の温度で熱処理して得たものである。熱処理温度が９００℃未満の場合には、これを負極材料とすると充放電ロスがあり、充放電容量が低下することがある。２８００℃以上の場合には、表面に被覆された炭素材料Ｃが高結晶化する場合があり、この場合には、これを負極材料とすると充放電ロスの増大と高速充放電特性の低下が起こることがある。
有機化合物Ｇとして難黒鉛性炭素前駆体を用いる場合には、２８００℃以上の熱処理温度にすることができる。難黒鉛性炭素前駆体を用いると２８００℃以上の熱処理でもそれほど結晶化が進まず、本発明が所望する一部に低い結晶性の炭素材料Ｃの被覆をすることができ、良好な充放電特性を示す複合炭素質材料Ｄが得られる。 The composite graphitic carbon material D is preferably obtained by adhering and / or impregnating an organic compound G to graphite B as a core material and heat-treating it at a temperature of 900 ° C. or more. More preferably, it is obtained by heat treatment at a temperature of 900 ° C. or more and less than 2800 ° C., particularly preferably 1150 ° C. or more and less than 2300 ° C. When the heat treatment temperature is lower than 900 ° C., if this is used as a negative electrode material, there is a charge / discharge loss, and the charge / discharge capacity may decrease. When the temperature is 2800 ° C. or higher, the carbon material C coated on the surface may be highly crystallized. In this case, when the carbon material C is used as a negative electrode material, charge / discharge loss increases and high-speed charge / discharge characteristics decrease. Sometimes.
When a non-graphitizable carbon precursor is used as the organic compound G, the heat treatment temperature can be set to 2800 ° C. or higher. When a non-graphitizable carbon precursor is used, crystallization does not proceed so much even at a heat treatment of 2800 ° C. or more, and a part of the carbon material C having low crystallinity desired by the present invention can be coated, and good charge / discharge characteristics can be obtained. Is obtained.

（黒鉛Ｂ）
芯材の黒鉛Ｂについては、各種天然黒鉛、人造黒鉛の中から選ぶことができるが、りん片状黒鉛、塊状黒鉛、球状黒鉛などが好ましい。内部構造としては、芯材中に適度な空隙を有するものが好ましい。芯材の黒鉛Ｂの平均粒径は１〜３０μｍの範囲であることが好ましい。比表面積は特に問わないが、炭素材料Ｃとなる有機化合物Ｇの分散が良好であることから大きい方が好ましく、０．５m2/g以上であることが好ましい。格子面間隔ｄ002 は、被覆後の放電容量を高めることから小さい方が好ましいが、熱処理工程での向上もあり得るため、特に限定されない。不純物を含んでいても構わない。 (Graphite B)
The graphite B as the core material can be selected from various natural graphites and artificial graphites, and flaky graphite, massive graphite, spherical graphite and the like are preferable. As the internal structure, one having an appropriate void in the core material is preferable. The average particle size of the graphite B of the core material is preferably in the range of 1 to 30 μm. The specific surface area is not particularly limited, but is preferably large because the dispersion of the organic compound G serving as the carbon material C is good, and is preferably 0.5 m 2 / g or more. The lattice spacing d 002 is preferably small from the viewpoint of increasing the discharge capacity after coating, but is not particularly limited because it may be improved in the heat treatment step. It may contain impurities.

（炭素材料Ｃの前駆体、有機化合物Ｇ）
炭素材料Ｃの前駆体としては、熱処理した際に、炭素分が残留する有機化合物Ｇを選定することが好ましい。また、熱処理後に、充放電反応を阻害または電解液の分解を促進させるような重金属、軽金属元素がほとんど残留しないものが好ましい。熱硬化性樹脂、熱可塑性樹脂、石炭系・石油系の重質油、石油系・石炭系のピッチなどが好ましい。特に炭素質微粒子（石炭の微粉、一次ＱＩ（キノリン不溶分）、カーボンブラック、炭素または黒鉛の微粒子など）を含むものが好ましい。また、有機化合物Ｇとして、難黒鉛性炭素前駆体を用いてもよい。難黒鉛性炭素前駆体はフェノール樹脂、フラン樹脂、ポリ塩化ビニリデン、スチレン−ジビニルベンゼン共重合体、ポリビニリデンジフルオライド、易黒鉛性ピッチの架橋変性体（酸化、硫黄処理などの生成物）、砂糖など固相で炭化反応が進むものが挙げられる。好ましいのはフェノール樹脂、フラン樹脂などである。
これら有機化合物Ｇをそのまま、または溶剤に溶解または分散して、またはスラリー化してから、芯材の黒鉛Ｂと混合した後、熱処理を行うことにより、低い結晶性を示す炭素材料Ｃが黒鉛Ｂに付着および／または含浸して、黒鉛Ｂの少なくとも一部が炭素材料Ｃにより被覆された複合黒鉛質炭素材料Ｄが得られる。 (Precursor of carbon material C, organic compound G)
As the precursor of the carbon material C, it is preferable to select an organic compound G in which a carbon content remains when heat-treated. In addition, it is preferable that a heavy metal or a light metal element that hardly inhibits the charge / discharge reaction or accelerates the decomposition of the electrolytic solution after the heat treatment remains. Thermosetting resin, thermoplastic resin, coal-based / petroleum-based heavy oil, petroleum-based / coal-based pitch, and the like are preferable. Particularly, those containing carbonaceous fine particles (coal fine powder, primary QI (quinoline insoluble matter), carbon black, carbon or graphite fine particles, etc.) are preferable. Further, as the organic compound G, a non-graphitizable carbon precursor may be used. Non-graphitizable carbon precursors are phenolic resin, furan resin, polyvinylidene chloride, styrene-divinylbenzene copolymer, polyvinylidene difluoride, crosslinked modified graphite pitch (products such as oxidation and sulfur treatment), Examples include those in which the carbonization reaction proceeds in the solid phase such as sugar. Preferred are phenol resins, furan resins and the like.
After the organic compound G is used as it is, dissolved or dispersed in a solvent, or slurried, and then mixed with the graphite B of the core material, a heat treatment is performed to convert the carbon material C having low crystallinity into the graphite B. By adhering and / or impregnating, a composite graphitic carbon material D in which at least a part of the graphite B is coated with the carbon material C is obtained.

有機化合物Ｇの黒鉛Ｂに対する混合割合としては、熱処理温度によっても異なるが、熱処理後に、黒鉛Ｂと炭素材料Ｃの合計質量に対して、炭素材料Ｃが０．５〜３０質量％、特に３〜２０質量％となるように調整するのが好ましい。炭素材料Ｃが過剰であると、これを負極材料とした場合に、充放電容量、充放電効率の低下を招き、それに伴い良好な高速放電特性が得られなくなることがある。逆に炭素材料Ｃが過少であると、これを負極材料とした場合に、放電容量は確保されるが、充放電効率、充電特性などの向上が認められないことがある。
前記複合黒鉛質炭素材料Ｄをリチウムイオン二次電池用負極材料として用いると、低い結晶性を示す炭素材料Ｃによって、充電特性が優れる。さらに、親水化された黒鉛質粒子Ａと併用することにより、黒鉛質粒子Ａの良好な放電特性を維持しつつも、混合した負極材料全体の充電特性を向上させることができ、サイクル特性が向上し、レート特性にも優れる。 The mixing ratio of the organic compound G to the graphite B varies depending on the heat treatment temperature, but after the heat treatment, the carbon material C is 0.5 to 30% by mass, and particularly preferably 3 to 30% by mass based on the total mass of the graphite B and the carbon material C. It is preferable to adjust so as to be 20% by mass. When the carbon material C is excessive, when the carbon material C is used as a negative electrode material, the charge / discharge capacity and the charge / discharge efficiency are reduced, and accordingly, good high-speed discharge characteristics may not be obtained. Conversely, if the amount of carbon material C is too small, when the carbon material C is used as a negative electrode material, the discharge capacity is ensured, but the charge / discharge efficiency, charge characteristics, and the like may not be improved.
When the composite graphitic carbon material D is used as a negative electrode material for a lithium ion secondary battery, the carbon material C having low crystallinity has excellent charging characteristics. Furthermore, by using in combination with the hydrophilized graphitic particles A, it is possible to improve the charge characteristics of the entire mixed negative electrode material while maintaining good discharge characteristics of the graphitic particles A, thereby improving cycle characteristics. And excellent rate characteristics.

（負極材料）
かくして得られた複合黒鉛質炭素材料Ｄを、親水化された黒鉛質粒子Ａと混合する。その混合比は、複合黒鉛質炭素材料Ｄに対する炭素材料Ｃの比率や親水化された黒鉛質粒子Ａの結晶性の程度によって異なるが、複合黒鉛質炭素材料Ｄ／黒鉛質粒子Ａの質量比で１０／９０〜８０／２０、好ましくは２０／８０〜７０／３０である。１０／９０未満であったり、８０／２０超であると、充放電特性を充分に発揮することができないことがある。
負極材料としては、特に前記メカノケミカル処理を施して表面を親水化した黒鉛質粒子Ａに、黒鉛Ｂに低い結晶性の炭素材料Ｃを被覆した複合黒鉛質炭素材料Ｄを混合したものが好ましく、特に、負極合剤ペーストを調製する時の結着剤の分散媒が水系結着剤であっても良好なサイクル特性およびレート特性を発現する。 (Negative electrode material)
The composite graphitic carbon material D thus obtained is mixed with the graphitic particles A that have been hydrophilized. The mixing ratio varies depending on the ratio of the carbon material C to the composite graphitic carbon material D and the degree of crystallinity of the hydrophilized graphitic particles A. However, the mixing ratio depends on the mass ratio of the composite graphitic carbon material D / graphitic particles A. It is 10 / 90-80 / 20, preferably 20 / 80-70 / 30. If it is less than 10/90 or more than 80/20, the charge / discharge characteristics may not be sufficiently exhibited.
As the negative electrode material, in particular, a material obtained by mixing a composite graphitic carbon material D in which graphite B is coated with a low-crystalline carbon material C to graphite particles A whose surface has been subjected to the mechanochemical treatment and which has been made hydrophilic, In particular, even when the dispersion medium of the binder at the time of preparing the negative electrode mixture paste is an aqueous binder, excellent cycle characteristics and rate characteristics are exhibited.

複合黒鉛質炭素材料Ｄと親水化された黒鉛質粒子Ａとの混合方法は、特に限定されないが、両者を粉体のままドライ状態で各種混合機を用いる方法が一般的である。また結着剤を加えて混合する場合には、各粒子の偏りがないように、すなわち、均一な分散が得られるように、充分な時間をかけて混合することが好ましい。   The method of mixing the composite graphitic carbon material D and the hydrophilized graphitic particles A is not particularly limited, but a method of using various mixers in a dry state in which both are powdered is common. In addition, when the binder is added and mixed, it is preferable to perform mixing for a sufficient time so that each particle is not biased, that is, to obtain a uniform dispersion.

前記負極材料を用い、水系結着剤と集電材とから作製した負極を含むリチウムイオン二次電池が、優れたサイクル特性、レート特性などの充放電特性を発現するのは、親水化された黒鉛質粒子Ａと、低い結晶性の炭素材料Ｃにより被覆された複合黒鉛質炭素材料Ｄとが、黒鉛質粒子Ａの周囲に均一に分散した水系結着剤によって強固に密着しているために、充放電を繰返しても該黒鉛質粒子Ａと該複合黒鉛質炭素材料Ｄとの密着性が保たれ、さらに該黒鉛質粒子Ａと該複合黒鉛質炭素材料Ｄと水系結着剤と集電体との強固な密着が維持されること、さらには、該水系結着剤が均一に薄膜化して黒鉛質粒子Ａの周囲に介在して、導電性、イオン伝導性、電解液浸透性などを阻害することがないことによるものと考えられる。   Using the negative electrode material, a lithium ion secondary battery including a negative electrode prepared from an aqueous binder and a current collector, exhibits excellent cycle characteristics, charge / discharge characteristics such as rate characteristics, and the like. Particles A and the composite graphitic carbon material D coated with the low-crystalline carbon material C are firmly adhered to each other by the aqueous binder uniformly dispersed around the graphite particles A. The adhesion between the graphitic particles A and the composite graphitic carbon material D is maintained even after repeated charge / discharge, and the graphite particles A, the composite graphitic carbon material D, the aqueous binder, and the current collector And the water-based binder is uniformly thinned and intervenes around the graphitic particles A, thereby inhibiting conductivity, ion conductivity, electrolyte permeability, etc. It is thought that it is not done.

さらに、サイクル特性、レート特性の向上を達成できるのは、黒鉛質粒子Ａ、複合黒鉛質炭素材料Ｄの芯材の黒鉛Ｂと黒鉛質粒子Ａ間の近接部分において、リチウムイオン、溶媒和したリチウムイオン、電子などが粒子間で高速に交換して互いの充電に優れた部分から優先的に充電反応が進行するが、その粒子から他の粒子への固体内拡散や粒子間拡散が起こり、充電反応が円滑に進行するためと考えられる。また、放電に関しても、異なる炭素または黒鉛質材料の放電に優れた部分からのリチウムイオンの放出による固相内リチウムイオン濃度の変化が他の粒子から迅速に起こるためではないかと考えられる。この効果は該黒鉛質粒子Ａと該炭素質材料Ｄとの密着性がバインダーの薄膜を介して十分に保たれるために発現し、これを達成するのに、本発明の組合せが適していると考えられる。   Further, the improvement of the cycle characteristics and the rate characteristics can be achieved only in the vicinity of the graphite particles A, the graphite B of the core material of the composite graphite carbon material D and the graphite particles A, by lithium ions and solvated lithium. Ions, electrons, etc. are exchanged between particles at high speed and the charging reaction proceeds preferentially from the part that is excellent in charging each other, but diffusion from the particles to other particles occurs in the solid or between particles, causing charging It is considered that the reaction proceeds smoothly. Also, regarding the discharge, it is considered that the change of the lithium ion concentration in the solid phase due to the release of lithium ions from the different carbon or graphitic material from the part excellent in discharge occurs quickly from other particles. This effect is exhibited because the adhesion between the graphite particles A and the carbonaceous material D is sufficiently maintained through the thin film of the binder, and the combination of the present invention is suitable for achieving this. it is conceivable that.

本発明の負極材料は、その特徴を生かして負極材料以外の用途に転用することもできるが、特に上記したリチウムイオン二次電池の負極材料として好適である。したがって本発明では、さらにこの負極材料を用いたリチウムイオン二次電池用負極、さらにはリチウムイオン二次電池が提供される。   The negative electrode material of the present invention can be diverted to uses other than the negative electrode material by utilizing its features, but is particularly suitable as the negative electrode material of the above-described lithium ion secondary battery. Therefore, the present invention further provides a negative electrode for a lithium ion secondary battery and a lithium ion secondary battery using the negative electrode material.

（負極）
本発明では、親水化された黒鉛質粒子Ａと、複合黒鉛質炭素材料Ｄとを含有する負極材料を用いて負極を作製するが、この際に、負極の作製に通常使用される導電材、改質材、添加剤などを混合してもよい。例えば、天然黒鉛、人造黒鉛、カーボンブラック、気相成長炭素繊維、またはこれらの黒鉛化物などを混合してもよい。これらの添加量は、一概には言えないが、０．１〜１０質量％である。 (Negative electrode)
In the present invention, a negative electrode is produced using a negative electrode material containing hydrophilic graphite particles A and a composite graphitic carbon material D. At this time, a conductive material usually used for producing a negative electrode, You may mix a modifier, an additive, etc. For example, natural graphite, artificial graphite, carbon black, vapor grown carbon fiber, or a graphitized product thereof may be mixed. Although the amount of these additions cannot be specified unconditionally, it is 0.1 to 10% by mass.

本発明における親水化された黒鉛質粒子Ａおよび複合黒鉛質炭素材料Ｄとを含有する負極材料を用いる負極の作製は、該負極材料の性能を充分に引き出し、かつ粉末に対する賦型性が高く、化学的、電気化学的に安定な負極を得ることができる成形方法であれば何ら制限されず、通常の成形方法に準じて行うことができる。   The production of a negative electrode using the negative electrode material containing the hydrophilized graphitic particles A and the composite graphitic carbon material D according to the present invention sufficiently draws out the performance of the negative electrode material, and has high moldability to powder, The molding method is not particularly limited as long as a molding method capable of obtaining a chemically and electrochemically stable negative electrode can be performed according to a usual molding method.

負極作製時には、前記負極材料に結着剤を加えた負極合剤を用いることができる。結着剤としては、電解質に対して化学的安定性、電気化学的安定性を有するものが好ましく、例えばポリフッ化ビニリデン、ポリテトラフルオロエチレン等のフッ素系樹脂、ポリエチレン、ポリビニルアルコール、さらにはカルボキシメチルセルロース、スチレンブタジエンゴムなどが用いられる。これらを併用することもできる。   When preparing the negative electrode, a negative electrode mixture obtained by adding a binder to the negative electrode material can be used. As the binder, those having chemical stability and electrochemical stability with respect to the electrolyte are preferable, for example, fluorine resins such as polyvinylidene fluoride and polytetrafluoroethylene, polyethylene, polyvinyl alcohol, and even carboxymethyl cellulose. And styrene-butadiene rubber. These can be used in combination.

なお、本発明では、前記負極材料を用いることにより、有機溶媒に溶解および／または分散する有機溶媒系結着剤はもちろんのこと、水溶性および／または水分散性の水系結着剤を用いても優れた充放電特性を発現する負極を得ることができる。
前記のうちでも、本発明の目的を達成し、効果を最大限に活かす上で、カルボキシメチルセルロース（水溶性）、ポリビニルアルコール（水溶性）、スチレンブタジエンゴム（水分散性）などの水系結着剤を用いることが特に好ましい。
結着剤は、通常、負極合剤の全量中０．５〜２０質量％の割合で使用されることが好ましい。 In the present invention, by using the negative electrode material, not only an organic solvent-based binder dissolved and / or dispersed in an organic solvent but also a water-soluble and / or water-dispersible water-based binder can be used. Also, a negative electrode exhibiting excellent charge / discharge characteristics can be obtained.
Among them, aqueous binders such as carboxymethylcellulose (water-soluble), polyvinyl alcohol (water-soluble), and styrene-butadiene rubber (water-dispersible) for achieving the object of the present invention and maximizing the effects. It is particularly preferred to use
Usually, the binder is preferably used in a ratio of 0.5 to 20% by mass based on the whole amount of the negative electrode mixture.

負極合剤の調製は、例えば、親水化された黒鉛質粒子Ａと、複合黒鉛質炭素材料Ｄを分級等によって適当な粒径に調整し、結着剤と混合することによって実施される。この負極合剤を、通常、集電材の片面もしくは両面に塗布して負極合剤層を形成する。また負極合剤を溶媒に分散させ、ペースト状にした後、集電材に塗布、乾燥すれば、集電材に均一かつ強固に接着した負極合剤層が形成される。ペーストは、翼式ホモミキサーにて３００〜３０００rpm 程度で撹拌することにより調製することができる。溶媒は負極合剤の調製に使用される通常の溶媒で差し支えない。   The preparation of the negative electrode mixture is carried out, for example, by adjusting the hydrophilized graphitic particles A and the composite graphitic carbon material D to an appropriate particle size by classification or the like, and mixing with a binder. This negative electrode mixture is usually applied to one or both surfaces of a current collector to form a negative electrode mixture layer. When the negative electrode mixture is dispersed in a solvent to form a paste, and then applied to the current collector and dried, a negative electrode mixture layer uniformly and firmly adhered to the current collector is formed. The paste can be prepared by stirring with a blade-type homomixer at about 300 to 3000 rpm. The solvent may be a usual solvent used for preparing the negative electrode mixture.

例えば、本発明の負極材料と、ポリフッ化ビニリデン等のフッ素系樹脂粉末あるいはカルボキシメチルセルロース、スチレンブタジエンゴムなどの水溶性または水分散性結着剤を、Ｎ−メチルピロリドン、ジメチルホルムアミド、水、アルコールなどの溶媒と混合してスラリーや溶液とした後、これを集電材に塗布すればよい。中でも、溶媒乾燥除去における安全面、環境面への影響を配慮して、水またはアルコールなどを溶媒として、カルボキシメチルセルロース、スチレンブタジエンゴムなどを溶解、分散させてなる水系スラリーを用いることが好ましい。
ペーストは、公知の攪拌機、混合機、混練機、ニーダーなどを用いて混合することにより調製される。 For example, the negative electrode material of the present invention, a water-soluble or water-dispersible binder such as fluorinated resin powder such as polyvinylidene fluoride or carboxymethylcellulose, styrene butadiene rubber, N-methylpyrrolidone, dimethylformamide, water, alcohol, etc. After mixing with the above solvent to form a slurry or a solution, this may be applied to the current collector. Above all, it is preferable to use an aqueous slurry obtained by dissolving and dispersing carboxymethylcellulose, styrene-butadiene rubber, or the like using water or alcohol as a solvent in consideration of the effects on the safety and the environment in removing and drying the solvent.
The paste is prepared by mixing using a known stirrer, mixer, kneader, kneader, or the like.

本発明による負極材料と結着剤とを混合してなる負極合剤を集電材に塗布し、乾燥した後の膜厚は１０〜２００μｍ、好ましくは２０〜２００μｍである。
また前記負極材料の粒子と結着剤としてのポリエチレン、ポリビニルアルコールなどの樹脂粉末とを乾式混合し、金型内でホットプレス成形して負極を製造することもできる。
負極合剤層を形成した後、プレス加工などの圧着を行うと、負極合剤層と集電材との接着強度をさらに高めることができる。 A negative electrode mixture obtained by mixing the negative electrode material according to the present invention and a binder is applied to a current collector, and the film thickness after drying is 10 to 200 μm, preferably 20 to 200 μm.
Alternatively, the negative electrode can be manufactured by dry-mixing the particles of the negative electrode material and a resin powder such as polyethylene or polyvinyl alcohol as a binder, and hot-press molding in a mold.
When pressure bonding such as pressing is performed after the formation of the negative electrode mixture layer, the adhesive strength between the negative electrode mixture layer and the current collector can be further increased.

負極に用いる集電材の形状は、特に限定されないが、箔状、またはメッシュ、エキスパンドメタルなどの網状のものなどが用いられる。集電材としては、例えば銅、ステンレス、ニッケルなどを挙げることができる。集電材の厚みは、箔状の場合、５〜２０μｍであることが好ましい。   The shape of the current collector used for the negative electrode is not particularly limited, and a foil shape, a mesh shape such as a mesh or expanded metal, or the like is used. Examples of the current collector include copper, stainless steel, and nickel. The thickness of the current collector is preferably 5 to 20 μm in the case of a foil shape.

（正極）
正極の材料（正極活物質）としては、充分量のリチウムを吸蔵／脱離し得るものを選択することが好ましい。そのような正極活物質としては、リチウム含有遷移金属酸化物、遷移金属カルコゲン化物、バナジウム酸化物（Ｖ2 Ｏ5 、Ｖ6 Ｏ13、Ｖ2 Ｏ4 、Ｖ3 Ｏ8 など）およびそのリチウム化合物などのリチウム含有化合物、一般式ＭX Ｍｏ6 Ｓ8-y （式中Ｘは０≦Ｘ≦４、Ｙは０≦Ｙ≦１の範囲の数であり、Ｍは遷移金属などの金属を表す）で表されるシェブレル相化合物、活性炭、活性炭素繊維などを用いることができる。 (Positive electrode)
As the material of the positive electrode (positive electrode active material), it is preferable to select a material capable of inserting and extracting a sufficient amount of lithium. Examples of such positive electrode active materials include lithium-containing transition metal oxides, transition metal chalcogenides, vanadium oxides (such as V 2 O 5 , V 6 O 13 , V 2 O 4 , V 3 O 8 ) and lithium compounds thereof. lithium-containing compounds such as the general formula M X Mo 6 S 8-y ( wherein X is 0 ≦ X ≦ 4, Y is a number in the range of 0 ≦ Y ≦ 1, M is a metal such as a transition metal ), Activated carbon, activated carbon fiber, and the like.

前記リチウム含有遷移金属酸化物は、リチウムと遷移金属との複合酸化物であり、リチウムと２種類以上の遷移金属を固溶したものであってもよい。リチウム含有遷移金属酸化物は、具体的には、ＬｉＭ（１）1-p Ｍ（２）p Ｏ2 （式中Ｐは０≦Ｐ≦１の範囲の数であり、Ｍ（１）、Ｍ（２）は少なくとも一種の遷移金属元素からなる。）またはＬｉＭ（１）2-Q Ｍ（２）Q Ｏ4 （式中Ｑは０≦Ｑ≦２の範囲の数であり、Ｍ（１）、Ｍ（２）は少なくとも一種の遷移金属元素からなる。）で示される。
前記において、Ｍで示される遷移金属元素としては、Ｃｏ、Ｎｉ、Ｍｎ、Ｃｒ、Ｔｉ、Ｖ、Ｆｅ、Ｚｎ、Ａｌ、Ｉｎ、Ｓｎなどが挙げられ、好ましくはＣｏ、Ｎｉ、Ｆｅ、Ｍｎ、Ｔｉ、Ｃｒ、Ｖ、Ａｌが挙げられる。 The lithium-containing transition metal oxide is a composite oxide of lithium and a transition metal, and may be a solid solution of lithium and two or more transition metals. The lithium-containing transition metal oxide is specifically LiM (1) 1-p M (2) p O 2 (where P is a number in the range of 0 ≦ P ≦ 1, M (1), M (1) (2) comprises at least one transition metal element) or LiM (1) 2-Q M (2) Q O 4 (where Q is a number in the range of 0 ≦ Q ≦ 2, and M (1) , M (2) comprises at least one transition metal element.)
In the above, examples of the transition metal element represented by M include Co, Ni, Mn, Cr, Ti, V, Fe, Zn, Al, In, and Sn, and preferably Co, Ni, Fe, Mn, and Ti. , Cr, V, and Al.

リチウム含有遷移金属酸化物としては、より具体的に、ＬｉＣｏＯ2 、Ｌｉp Ｎｉq Ｍ1-q Ｏ2(ＭはＮｉを除く前記遷移金属元素、好ましくはＣｏ、Ｆｅ、Ｍｎ、Ｔｉ、Ｃｒ、Ｖ、Ａｌから選ばれる少なくとも一種、０．０５≦ｐ≦１．１０、０．５≦ｑ≦１．０である。）で示されるリチウム複合酸化物、ＬｉＮｉＯ2 、ＬｉＭｎＯ2 、ＬｉＭｎ2 Ｏ4 、ＬｉＮｉ0.9 Ｃｏ0.1 Ｏ2 、ＬｉＮｉ0.5 Ｃｏ 0.5Ｏ2 などが挙げられる。 Examples of the lithium-containing transition metal oxide, more specifically, LiCoO 2, Lip Ni q M 1-q O 2 (M is the transition metal elements excluding Ni, preferably Co, Fe, Mn, Ti, Cr, V , Al, at least one selected from the group consisting of 0.05 ≦ p ≦ 1.10 and 0.5 ≦ q ≦ 1.0), LiNiO 2 , LiMnO 2 , LiMn 2 O 4 , LiNi 0.9 Co 0.1 O 2 and LiNi 0.5 Co 0.5 O 2 are exemplified.

前記のようなリチウム含有遷移金属酸化物は、例えば、リチウム、遷移金属の酸化物または塩類を出発原料とし、これら出発原料を所望の組成に応じて混合し、酸素雰囲気下、６００〜１０００℃の温度で焼成することにより得ることができる。なお出発原料は酸化物または塩類に限定されず、水酸化物などでもよい。
本発明では、正極活物質は、前記化合物を単独で使用しても２種類以上併用してもよい。例えば、正極材料に炭酸リチウムなどの炭酸アルカリ塩を添加することもできる。 As the lithium-containing transition metal oxide, for example, lithium, an oxide or a salt of a transition metal is used as a starting material, and these starting materials are mixed according to a desired composition, and the mixture is heated to 600 to 1000 ° C. under an oxygen atmosphere. It can be obtained by firing at a temperature. The starting material is not limited to oxides or salts, and may be a hydroxide or the like.
In the present invention, as the positive electrode active material, the above compounds may be used alone or in combination of two or more. For example, an alkali carbonate such as lithium carbonate can be added to the positive electrode material.

このような正極材料によって正極を形成するには、例えば正極材料と結着剤および電極に導電性を付与するための導電剤よりなる正極合剤を集電材の両面に塗布することで正極合剤層を形成する。結着剤としては、負極で例示したものがいずれも使用可能である。導電剤としては、例えば炭素材料、黒鉛やカーボンブラックが用いられる。   In order to form a positive electrode using such a positive electrode material, for example, a positive electrode mixture composed of a positive electrode material, a binder, and a conductive agent for imparting conductivity to the electrode is applied to both surfaces of the current collector. Form a layer. As the binder, any of those exemplified for the negative electrode can be used. As the conductive agent, for example, a carbon material, graphite or carbon black is used.

集電材の形状は特に限定されず、箱状、またはメッシュ、エキスパンドメタルなどの網状などのものが用いられる。集電材の基板としては、アルミニウム、ステンレス、ニッケルなどを挙げることができる。その厚さは、１０〜４０μｍが好適である。
また正極の場合も負極と同様に、正極合剤を溶剤中に分散させることでペースト状にし、このペースト状の正極合剤を集電材に塗布、乾燥することによって正極合剤層を形成してもよく、正極合剤層を形成した後、さらにプレス加圧等の圧着を行っても構わない。これにより正極合剤層が均一かつ強固に集電材に接着される。 The shape of the current collector is not particularly limited, and may be a box, a mesh, or a mesh such as expanded metal. Examples of the current collector substrate include aluminum, stainless steel, and nickel. The thickness is preferably from 10 to 40 μm.
In the case of the positive electrode, similarly to the negative electrode, the positive electrode mixture is dispersed in a solvent to form a paste, and the paste-like positive electrode mixture is applied to a current collector, and dried to form a positive electrode mixture layer. After the positive electrode mixture layer is formed, pressure bonding such as pressurization may be further performed. Thereby, the positive electrode mixture layer is uniformly and firmly adhered to the current collector.

以上のような負極および正極を形成するに際しては、従来公知の導電剤や結着剤などの各種添加剤を適宜に使用することができる。   In forming the negative electrode and the positive electrode as described above, conventionally known various additives such as a conductive agent and a binder can be appropriately used.

（電解質）
本発明に用いられる電解質としては通常の非水電解液に使用されている電解質塩を用いることができ、例えば、ＬｉＰＦ6 、ＬｉＢＦ4 、ＬｉＡｓＦ6 、ＬｉＣｌＯ4 、ＬｉＢ（Ｃ6 Ｈ5 ）4 、ＬｉＣｌ、ＬｉＢｒ、ＬｉＣＦ3 ＳＯ3 、ＬｉＣＨ3 ＳＯ3 、ＬｉＮ（ＣＦ3 ＳＯ2 ）2 、ＬｉＣ（ＣＦ3 ＳＯ2 ）3 、ＬｉＮ（ＣＦ3 ＣＨ2 ＯＳＯ2 ）2 、ＬｉＮ（ＣＦ3 ＣＦ2 ＯＳＯ2 ）2 、ＬｉＮ（ＨＣＦ2 ＣＦ2 ＣＨ2 ＯＳＯ2 ）2 、ＬｉＮ｛（ＣＦ3 ）2 ＣＨＯＳＯ2 ｝2 、ＬｉＢ｛Ｃ6 Ｈ3 （ＣＦ3 ）2 ｝4 、ＬｉＡｌＣｌ4 、ＬｉＳｉＦ6 などのリチウム塩などを用いることができる。特にＬｉＰＦ6 、ＬｉＢＦ4 が酸化安定性の点から好ましく用いられる。
電解液中の電解質塩濃度は０．１〜５mol/L が好ましく、０．５〜３．０mol/L がより好ましい。 (Electrolytes)
As the electrolyte used for the present invention can be used an electrolyte salt used in the conventional non-aqueous electrolyte solution, for example, LiPF 6, LiBF 4, LiAsF 6, LiClO 4, LiB (C 6 H 5) 4, LiCl, LiBr, LiCF 3 SO 3 , LiCH 3 SO 3, LiN (CF 3 SO 2) 2, LiC (CF 3 SO 2) 3, LiN (CF 3 CH 2 OSO 2) 2, LiN (CF 3 CF 2 OSO 2 ) 2 , LiN (HCF 2 CF 2 CH 2 OSO 2 ) 2 , LiN ｛(CF 3 ) 2 CHOSO 2 ｝ 2 , LiB ｛C 6 H 3 (CF 3 ) 2 ｝ 4 , LiAlCl 4 , LiSiF 6 A lithium salt or the like can be used. Particularly, LiPF 6 and LiBF 4 are preferably used from the viewpoint of oxidation stability.
The electrolyte salt concentration in the electrolytic solution is preferably from 0.1 to 5 mol / L, more preferably from 0.5 to 3.0 mol / L.

前記非水電解質は、液系の非水電解液としてもよいし、固体電解質あるいはゲル電解質など高分子電解質としてもよい。前者の場合、非水電解質電池は、いわゆるリチウムイオン電池として構成され、後者の場合、非水電解質電池は、高分子固体電解質電池、高分子ゲル電解質電池などの高分子電解質電池として構成される。   The non-aqueous electrolyte may be a liquid non-aqueous electrolyte or a polymer electrolyte such as a solid electrolyte or a gel electrolyte. In the former case, the non-aqueous electrolyte battery is configured as a so-called lithium ion battery, and in the latter case, the non-aqueous electrolyte battery is configured as a polymer electrolyte battery such as a polymer solid electrolyte battery and a polymer gel electrolyte battery.

液系の非水電解質液とする場合には、溶媒として、エチレンカーボネート、プロピレンカーボネート、ジメチルカーボネート、ジエチルカーボネート、１，1 −または１，2 −ジメトキシエタン、１，2 −ジエトキシエタン、テトラヒドロフラン、２−メチルテトラヒドロフラン、γ−ブチロラクトン、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、ジメチルサルファイトなどの非プロトン性有機溶媒を用いることができる。
また、電池の性能を向上させる添加剤などを含有していても差し支えない。 When a liquid nonaqueous electrolyte solution, as a solvent, ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, 1,1- or 1,2-dimethoxyethane, 1,2-diethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, γ-butyrolactone, 1,3-dioxolane, 4-methyl-1,3-dioxolane, anisole, diethyl ether, sulfolane, methylsulfolane, acetonitrile, chloronitrile, propionitrile, trimethyl borate, silicic acid Tetramethyl, nitromethane, dimethylformamide, N-methylpyrrolidone, ethyl acetate, trimethyl orthoformate, nitrobenzene, benzoyl chloride, benzoyl bromide, tetrahydrothiophene, dimethylsulfoxide, 3- An aprotic organic solvent such as methyl-2-oxazolidone, ethylene glycol, and dimethyl sulfite can be used.
Further, an additive for improving the performance of the battery may be contained.

非水電解質を高分子固体電解質、高分子ゲル電解質などの高分子電解質とする場合には、可塑剤（非水電解液）でゲル化されたマトリクスの高分子化合物を含むが、このマトリクス高分子化合物としては、ポリエチレンオキサイドやその架橋体などのエーテル系高分子化合物、ポリメタクリレート系高分子化合物、ポリアクリレート系高分子化合物、ポリビニリデンフルオライドやビニリデンフルオライド−ヘキサフルオロプロピレン共重合体などのフッ素系高分子化合物などを単独、もしくは混合して用いることができる。
これらの中で、酸化還元安定性の観点などから、ポリビニリデンフルオライドやビニリデンフルオライド−ヘキサフルオロプロピレン共重合体などのフッ素系高分子化合物を用いることが望ましい。 When the non-aqueous electrolyte is a polymer electrolyte such as a polymer solid electrolyte or a polymer gel electrolyte, a matrix polymer compound gelled with a plasticizer (non-aqueous electrolyte) is contained. Examples of the compound include ether polymer compounds such as polyethylene oxide and its crosslinked product, polymethacrylate polymer compounds, polyacrylate polymer compounds, and fluorine such as polyvinylidene fluoride and vinylidene fluoride-hexafluoropropylene copolymer. A system polymer compound or the like can be used alone or as a mixture.
Among these, it is desirable to use a fluorine-based polymer compound such as polyvinylidene fluoride or a vinylidene fluoride-hexafluoropropylene copolymer from the viewpoint of oxidation-reduction stability.

これら高分子固体電解質または高分子ゲル電解質には可塑剤が含有されるが、可塑剤としては前記の電解質塩や非水溶媒が使用可能である。高分子ゲル電解質の場合、可塑剤である非水電解液中の電解質塩濃度は０．１〜５mol/L が好ましく、０．５〜２．０mol/L がより好ましい。
このような高分子電解質の製造方法は特に制限されないが、例えば、マトリクスを形成する高分子化合物、リチウム塩および非水溶媒（可塑剤）を混合し、加熱して高分子化合物を溶融する方法、有機溶剤に高分子化合物、リチウム塩および非水溶媒を溶解させた後、混合用有機溶剤を蒸発させる方法、ならびに高分子電解質の原料となる重合性モノマー、リチウム塩および非水溶媒を混合し、混合物に紫外線、電子線または分子線などを照射して重合性モノマーを重合させ高分子電解質を製造する方法などを挙げることができる。
また、前記固体電解質中の溶媒の混合割合が１０〜９０質量％であると、導電率が高く、かつ機械的強度が高く、成膜しやすいので好ましく、より好ましくは３０〜８０質量％である。 These polymer solid electrolytes or polymer gel electrolytes contain a plasticizer. As the plasticizer, the above-mentioned electrolyte salts and non-aqueous solvents can be used. In the case of the polymer gel electrolyte, the concentration of the electrolyte salt in the non-aqueous electrolyte as a plasticizer is preferably 0.1 to 5 mol / L, more preferably 0.5 to 2.0 mol / L.
The method for producing such a polymer electrolyte is not particularly limited. For example, a method of mixing a polymer compound forming a matrix, a lithium salt and a non-aqueous solvent (plasticizer), and heating to melt the polymer compound; After dissolving a polymer compound, a lithium salt and a non-aqueous solvent in an organic solvent, a method of evaporating the organic solvent for mixing, and a polymerizable monomer serving as a raw material of a polymer electrolyte, a lithium salt and a non-aqueous solvent are mixed, A method of irradiating the mixture with an ultraviolet ray, an electron beam, a molecular beam, or the like to polymerize the polymerizable monomer to produce a polymer electrolyte can be used.
Further, when the mixing ratio of the solvent in the solid electrolyte is 10 to 90% by mass, the conductivity is high, the mechanical strength is high, and the film is easily formed, so that it is more preferably 30 to 80% by mass. .

（リチウムイオン二次電池）
リチウムイオン二次電池は、通常、負極、正極および非水電解質を主たる電池構成要素とし、正極、負極はそれぞれリチウムイオンの担持体からなり、充放電過程におけるリチウムイオンの出入は層間で行われる。そして充電時にはリチウムイオンが負極中に吸蔵され、放電時には負極から脱離する電池機構を構成する。
本発明のリチウムイオン二次電池は、本発明の負極材料を用いること以外は特に限定されず、他の電池構成要素については一般的なリチウムイオン二次電池の要素に準じる。 (Lithium ion secondary battery)
A lithium ion secondary battery usually includes a negative electrode, a positive electrode, and a non-aqueous electrolyte as main battery components. The positive electrode and the negative electrode are each made of a lithium ion carrier, and lithium ions enter and leave during a charge / discharge process between layers. Then, a battery mechanism is constructed in which lithium ions are occluded in the negative electrode during charging and detached from the negative electrode during discharging.
The lithium ion secondary battery of the present invention is not particularly limited except that the negative electrode material of the present invention is used, and other battery components are in accordance with general lithium ion secondary battery elements.

本発明のリチウムイオン二次電池に使用するセパレータは、特に限定されるものではないが、例えば織布、不織布、合成樹脂製微多孔膜などが挙げられる。特に合成樹脂製微多孔膜が好適に用いられるが、その中でもポリオレフィン系微多孔膜が、厚さ、膜強度、膜抵抗の面で好適である。具体的には、ポリエチレンおよびポリプロピレン製微多孔膜、またはこれらを複合した微多孔膜などである。   The separator used in the lithium ion secondary battery of the present invention is not particularly limited, and examples thereof include a woven fabric, a nonwoven fabric, and a microporous synthetic resin membrane. In particular, a synthetic resin microporous membrane is preferably used, and among them, a polyolefin-based microporous membrane is preferable in terms of thickness, film strength, and film resistance. Specifically, it is a microporous film made of polyethylene and polypropylene, or a microporous film obtained by combining these.

本発明のリチウムイオン二次電池において、ゲル電解質を用いることも可能である。
ゲル電解質二次電池は、負極、正極およびゲル電解質を、例えば負極、ゲル電解質、正極の順で積層し、電池外装材内に収容することで構成される。なお、さらに負極と正極の外側にゲル電解質を配するようにしてもよい。 In the lithium ion secondary battery of the present invention, a gel electrolyte can be used.
The gel electrolyte secondary battery is configured by laminating a negative electrode, a positive electrode, and a gel electrolyte in the order of, for example, a negative electrode, a gel electrolyte, and a positive electrode, and then housing the battery in a battery exterior material. Note that a gel electrolyte may be further provided outside the negative electrode and the positive electrode.

本発明に係るリチウムイオン二次電池の構造は任意であり、その形状、形態について特に限定されるものではなく、円筒型、角型、コイン型、ボタン型などの中から任意に選択することができる。より安全性の高い密閉型非水電解液電池を得るためには、過充電などの異常時に電池内圧上昇を感知して電流を遮断させる手段を備えたものであることが好ましい。アルミラミネートフィルムなどに封入した構造とすることもできる。   The structure of the lithium ion secondary battery according to the present invention is optional, and its shape and form are not particularly limited, and can be arbitrarily selected from a cylindrical type, a square type, a coin type, a button type, and the like. it can. In order to obtain a sealed non-aqueous electrolyte battery with higher safety, it is preferable to provide a means for interrupting the current by detecting an increase in battery internal pressure when an abnormality such as overcharging occurs. The structure may be sealed in an aluminum laminate film or the like.

以下に、本発明を実施例および比較例によって具体的に説明する。本発明はこれらの実施例に限定されるものではない。また、以下の実施例および比較例では、本発明の負極材料を用いて、図３に示すような構造の評価用のボタン型電池を作製して評価した。実電池は、本発明の概念に基き、公知の方法に準じて作製することができる。   Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. The present invention is not limited to these examples. In the following Examples and Comparative Examples, a button-type battery for evaluation having a structure as shown in FIG. 3 was prepared using the negative electrode material of the present invention, and evaluated. The actual battery can be manufactured according to a known method based on the concept of the present invention.

粒子の物性は下記のように測定した。
平均粒径は、レーザー回折式粒度分布計により粒度分布の累積度数が体積百分率で５０％となる粒径とした。
格子面間隔ｄ002 は前述したＸ線広角回折法により求めた。
真比重はブタノールを溶媒に用いる液相置換法で測定した。
比表面積は、窒素ガス吸着によるＢＥＴ比表面積である。
水の浸透量（親水性）は、黒鉛質粒子１５ｇを、２５℃で底部が内径３６ｍｍの金網およびろ紙からなる円筒容器に充填し、パウダテスタ（PTR ；ホソカワミクロン（株）製）を用い、１min 間に６０回のタッピングを３min 行ない、１８０回タッピングした後、該容器の底部を水面に接触させた３０sec 後の浸透量である。浸透量はペネトアナライザー（ホソカワミクロン（株）製）を用いて測定した。
Ｒ値は、レーザーラマン分光分析装置（NR-1800 ；日本分光（株）製）を用い、励起光は５１４．５ｎｍのアルゴンイオンレーザー、照射面積は５０μｍφで分析し、Ｄバンド１３６０cm-1ピークの強度をＩＤ、Ｇバンドの１５８０cm-1ピークの強度をＩＧとしたときのＩＤ／ＩＧである。 The physical properties of the particles were measured as described below.
The average particle size was determined to be a particle size at which the cumulative frequency of the particle size distribution was 50% by volume percentage using a laser diffraction particle size distribution meter.
The lattice spacing d 002 was determined by the X-ray wide-angle diffraction method described above.
The true specific gravity was measured by a liquid phase replacement method using butanol as a solvent.
The specific surface area is a BET specific surface area by nitrogen gas adsorption.
The amount of water permeation (hydrophilicity) was measured by filling 15 g of graphite particles at 25 ° C. in a cylindrical container made of a wire mesh and filter paper having an inner diameter of 36 mm, and using a powder tester (PTR; manufactured by Hosokawa Micron Corporation) for 1 minute. After tapping 60 times for 3 minutes and tapping 180 times, the amount of permeation 30 seconds after the bottom of the container was brought into contact with the water surface. The permeation amount was measured using a penetro analyzer (manufactured by Hosokawa Micron Corporation).
The R value was analyzed using a laser Raman spectrometer (NR-1800; manufactured by JASCO Corporation) with an excitation light of 514.5 nm using an argon ion laser and an irradiation area of 50 μmφ, and the D band at 1360 cm −1 peak was analyzed. ID / IG when the intensity is ID and the intensity of the G band at 1580 cm -1 is IG.

（実施例１）
（親水化された黒鉛質粒子Ａ１の作製）
コールタールピッチを熱処理してなるメソフェーズ小球体（ＪＦＥケミカル（株）製、平均粒径：２５μｍ）を３０００℃で黒鉛化し、メソフェーズ小球体の黒鉛質粒子Ｅ１を得た。該粒子Ｅ１は球状であり、格子面間隔ｄ002 が０．３３６２ｎｍ、真比重が２．２２８であった。また比表面積は０．４５m2/gであった。浸透量（親水性）は０．１５ｇ（３０sec ）であった。 (Example 1)
(Preparation of hydrophilized graphitic particles A1)
Mesophase microspheres (manufactured by JFE Chemical Co., Ltd., average particle size: 25 μm) obtained by heat-treating coal tar pitch were graphitized at 3000 ° C. to obtain graphitic particles E1 of mesophase microspheres. Particles E1 are spherical, the lattice spacing d 002 is 0.3362Nm, a true specific gravity of 2.228. The specific surface area was 0.45 m 2 / g. The amount of penetration (hydrophilicity) was 0.15 g (30 sec).

ついで、この黒鉛質粒子Ｅ１に、図２に示すような概略構造のメカノケミカル処理装置（（株）奈良機械製作所製「ハイブリダイゼーションシステム」）を用いて、下記の条件でメカノケミカル処理を行った。すなわち、回転ローターの周速４０m/sec で処理時間６min の条件下で処理することにより、該装置内に投入された黒鉛質粒子Ｅ１を分散しながら主として衝撃力、分子間相互作用を含めた圧縮力、摩擦力、剪断力などの機械的作用を繰返し付与した。得られた親水化された黒鉛質粒子Ａ１は球状を呈しており、平均粒径は２４μｍであった。浸透量（親水性）は１．３ｇ（３０sec ）であった。   Next, the graphite particles E1 were subjected to a mechanochemical treatment under the following conditions using a mechanochemical treatment apparatus having a schematic structure as shown in FIG. 2 (“Hybridization System” manufactured by Nara Machinery Co., Ltd.). . That is, by performing the treatment at a peripheral speed of the rotating rotor of 40 m / sec for a treatment time of 6 min, the graphite particles E1 charged into the apparatus are dispersed while the compression mainly including the impact force and the intermolecular interaction is performed. Mechanical actions such as force, friction, and shear were repeatedly applied. The obtained hydrophilic graphite particles A1 had a spherical shape and an average particle size of 24 μm. The permeation amount (hydrophilicity) was 1.3 g (30 sec).

（低い結晶性炭素材料Ｃ１の被覆を有する複合黒鉛質炭素材料Ｄ１の作製）
オートクレーブに、芯材として天然黒鉛Ｂ１（中越黒鉛（株）製ＢＦ１０Ａ、平均粒径１０μｍ、格子面間隔ｄ002 が０．３３５６ｎｍ、Ｒ値０．０９）１００質量部を入れ、さらに有機化合物としてのコールタールピッチＧ１ ２０質量部をタール中油１００質量部に溶解させた溶液を入れ、攪拌下に１４０℃に加熱した。加熱を継続した後、減圧蒸留によってタール中油を除去し、ピッチが表面および／または内部に付着および／または含浸した複合黒鉛質炭素材料の前駆体を得た。ついで、これをステンレス製るつぼに充填し、焼成炉にて不活性ガス流通下、５００℃で加熱した後、アトマイザーで粉砕した。さらに、これを１０００℃で熱処理し、低い結晶性炭素材料Ｃ１が被覆された複合黒鉛質炭素材料Ｄ１を得た。各々の加熱または熱処理の収率から、複合黒鉛質炭素材料Ｄ１中の炭素材料Ｃ１の質量を算出したところ、８質量％に相当した。Ｒ値は０．２８であった。 (Production of composite graphitic carbon material D1 having coating of low crystalline carbon material C1)
In an autoclave, 100 parts by mass of natural graphite B1 (BF10A manufactured by Chuetsu Graphite Co., Ltd., average particle diameter 10 μm, lattice spacing d 002 is 0.3356 nm, R value 0.09) as a core material, and further as an organic compound A solution prepared by dissolving 20 parts by mass of coal tar pitch G1 in 100 parts by mass of medium in tar was added, and heated to 140 ° C. with stirring. After the heating was continued, the oil in the tar was removed by distillation under reduced pressure to obtain a precursor of a composite graphitic carbon material having a pitch adhered to and / or impregnated on the surface and / or inside. Next, this was filled in a stainless steel crucible, heated at 500 ° C. in a firing furnace under an inert gas flow, and pulverized by an atomizer. Further, this was heat-treated at 1000 ° C. to obtain a composite graphitic carbon material D1 coated with a low crystalline carbon material C1. When the mass of the carbon material C1 in the composite graphite carbon material D1 was calculated from the yield of each heating or heat treatment, it was equivalent to 8% by mass. The R value was 0.28.

前記親水化された黒鉛質粒子Ａ１と複合黒鉛質炭素材料Ｄ１とを含む負極材料を用いて、水溶媒系の負極合剤ペーストを調製した。
（負極合剤ペーストＨ１の調製）
プラネタリーミキサーに、親水化された黒鉛質粒子Ａ１と複合黒鉛質炭素材料Ｄ１とを質量比が６０：４０となるように入れ、ドライ状態で攪拌した後、固形分でそれぞれ次の質量％となるようにカルボキシメチルセルロースナトリウム１質量％、カルボキシ変性スチレンブタジエンゴムラテックスエマルジョン（ＪＳＲ（株）製）１質量％と水を加えて混合し、引き続き攪拌を行い、水溶媒系の負極合剤ペーストＨ１を調製した。 An aqueous solvent-based negative electrode mixture paste was prepared using the negative electrode material containing the hydrophilized graphitic particles A1 and the composite graphitic carbon material D1.
(Preparation of negative electrode mixture paste H1)
In a planetary mixer, the mass ratio of the graphitized graphite particles A1 and the composite graphitic carbon material D1 is 60:40, and the mixture is stirred in a dry state. 1% by mass of sodium carboxymethylcellulose, 1% by mass of a carboxy-modified styrene-butadiene rubber latex emulsion (manufactured by JSR Corporation) and water were added and mixed, followed by stirring to obtain a water solvent-based negative electrode mixture paste H1. Prepared.

（作用電極の作製）
前記負極合剤ペーストＨ１を、銅箔（厚さ１６μｍ）上に塗布し、さらに真空中９０℃で溶媒を揮発させて乾燥させた。次に、形成された負極合層Ｈ１をローラープレスによって加圧し、さらに直径１５．５ｍｍの円形状に打ち抜くことで、銅箔に密着した負極合剤層Ｈ１（厚さ６０μｍ）を有する作用電極を作製した。 (Production of working electrode)
The negative electrode mixture paste H1 was applied on a copper foil (16 μm in thickness), and the solvent was evaporated in a vacuum at 90 ° C. and dried. Next, the formed negative electrode mixture layer H1 was pressed by a roller press, and was further punched out into a circular shape having a diameter of 15.5 mm to form a working electrode having a negative electrode mixture layer H1 (thickness 60 μm) adhered to the copper foil. Produced.

（対極の作製）
リチウム金属箔（厚さ５００μｍ）をニッケルネットに押付け、直径１５．５ｍｍの円形状に打ち抜いて、ニッケルネットからなる集電材（厚さ２５０μｍ）と、該集電材に密着したリチウム金属箔からなる対極を作製した。 (Preparation of counter electrode)
A lithium metal foil (thickness: 500 μm) is pressed against a nickel net and punched into a circular shape having a diameter of 15.5 mm, and a current collector made of a nickel net (thickness: 250 μm) and a counter electrode made of a lithium metal foil in close contact with the current collector Was prepared.

（電解液）
エチレンカーボネート３３mol%、メチルエチルカーボネート６７mol%の割合で混合してなる混合溶媒に、ＬｉＰＦ6 を１mol/dm3 となる濃度で溶解させ、非水電解液を調製した。得られた非水電解質液をポリプロピレン多孔質膜に含浸させ、電解液が含浸したセパレータを作製した。 (Electrolyte)
LiPF 6 was dissolved at a concentration of 1 mol / dm 3 in a mixed solvent obtained by mixing ethylene carbonate at 33 mol% and methyl ethyl carbonate at 67 mol% to prepare a non-aqueous electrolyte. The obtained non-aqueous electrolyte solution was impregnated into a porous polypropylene membrane to produce a separator impregnated with the electrolyte solution.

（評価電池の作製）
評価電池として図３に示すボタン型評価電池を作製した。
外装カップ３１と外装缶３３とは、その周縁部において絶縁ガスケット３６を介してかしめられた密閉構造を有し、その内部に外装缶３３の内面から順に、ニッケルネットからなる集電材３７ａ、リチウム箔よりなる円盤状の対極３４、電解質液が含浸したセパレータ３５、負極合剤を有する円盤状の作用電極３２および銅箔からなる集電材３７ｂが積層された電池構造である。 (Production of evaluation battery)
A button-type evaluation battery shown in FIG. 3 was produced as an evaluation battery.
The outer cup 31 and the outer can 33 have a sealed structure that is caulked at the peripheral edge thereof via an insulating gasket 36, and a current collector 37 a made of nickel net and a lithium foil A battery structure is formed by laminating a disc-shaped counter electrode 34, a separator 35 impregnated with an electrolyte solution, a disc-shaped working electrode 32 having a negative electrode mixture, and a current collector 37b made of copper foil.

評価電池は、電解液を含浸させたセパレータ３５を、集電材３７ｂに密着した作用電極３２と、集電材３７ａに密着した対極３４との間に挟んで積層した後、作用電極３２を外装カップ３１内に、対極３４を外装缶３３内に収容して、外装カップ３１と外装缶３３とを合わせ、外装カップ３１と外装缶３３との周縁部を絶縁ガスケット３６を介してかしめ密閉して作製した。
評価電池は、実電池において、負極用活物質として使用可能な黒鉛質粒子を含有する作用電極３２と、リチウム金属箔からなる対極３４とから構成される電池である。 In the evaluation battery, the separator 35 impregnated with the electrolytic solution was laminated between the working electrode 32 in close contact with the current collector 37b and the counter electrode 34 in close contact with the current collector 37a. Inside, the counter electrode 34 is accommodated in the outer can 33, the outer cup 31 and the outer can 33 are combined, and the outer peripheral portion of the outer cup 31 and the outer can 33 is caulked and sealed via an insulating gasket 36 to produce the battery. .
The evaluation battery is an actual battery that includes a working electrode 32 containing graphite particles that can be used as an active material for a negative electrode, and a counter electrode 34 made of a lithium metal foil.

前記評価電池について、２５℃で下記のような充放電試験を行い、放電容量、初期充放電効率、急速充電効率およびサイクル特性を測定した。黒鉛質粒子１ｇ当りの放電容量（mAh/g ）、初期充放電効率（％）、急速充電効率（％）、急速放電効率（％）およびサイクル特性を表２に示した。   The following battery was subjected to the following charge / discharge test at 25 ° C. to measure the discharge capacity, initial charge / discharge efficiency, rapid charge efficiency, and cycle characteristics. Table 2 shows the discharge capacity (mAh / g), initial charge / discharge efficiency (%), rapid charge efficiency (%), rapid discharge efficiency (%), and cycle characteristics per gram of the graphite particles.

（放電容量）（初期充放電効率）
０．９ｍＡの電流値で回路電圧が０ｍＶに達するまで定電流充電を行い、回路電圧が０ｍＶに達した時点で定電圧充電に切替え、さらに電流値が２０μＡになるまで充電を続けた後、その間の通電量から充電容量を求めた。その後、１２０min 間休止した。
次に０．９ｍＡの電流値で、回路電圧が１．５Ｖに達するまで定電流放電を行い、この間の通電量から放電容量を求めた。これを第１サイクルとした。次式１から初期充放電効率を計算した。
初期充放電効率（％）＝（第１サイクルにおける放電容量／第１サイクルにおける 充電容量）×１００ 式１
なおこの試験では、リチウムイオンを負極材料中に吸蔵する過程を充電、負極材料から脱離する過程を放電とした。 (Discharge capacity) (initial charge / discharge efficiency)
At a current value of 0.9 mA, constant-current charging is performed until the circuit voltage reaches 0 mV. When the circuit voltage reaches 0 mV, switching to constant-voltage charging is performed. Further, charging is continued until the current value reaches 20 μA. The charging capacity was determined from the amount of current supplied. Thereafter, the operation was stopped for 120 minutes.
Next, constant current discharge was performed at a current value of 0.9 mA until the circuit voltage reached 1.5 V, and the discharge capacity was determined from the amount of current supplied during this time. This was the first cycle. The initial charge / discharge efficiency was calculated from the following equation 1.
Initial charge / discharge efficiency (%) = (discharge capacity in first cycle / charge capacity in first cycle) × 100 Equation 1
In this test, the process of occluding lithium ions in the negative electrode material was defined as charging, and the process of releasing lithium ions from the negative electrode material was defined as discharging.

（急速充電効率）
前記に引き続き、第２サイクルにて高速充電を行なった。
電流値を第１サイクルの５倍の４．５ｍＡとして、回路電圧が０ｍＶに達するまで定電流充電を行い、充電容量を求め、次式２から急速充電効率を計算した。
急速充電効率（％）＝（第２サイクルにおける定電流充電容量／第１サイクルにお ける充電容量）×１００ 式２ (Rapid charging efficiency)
Following the above, high-speed charging was performed in the second cycle.
With the current value set to 4.5 mA, which is five times the first cycle, constant current charging was performed until the circuit voltage reached 0 mV, the charging capacity was determined, and the rapid charging efficiency was calculated from the following equation 2.
Rapid charging efficiency (%) = (constant current charging capacity in the second cycle / charging capacity in the first cycle) × 100 Equation 2

（急速放電効率）
引き続き、第３サイクルにて高速放電を行なった。
電流値を第１サイクルの１５倍の１３．５ｍＡとして、回路電圧が２．５ｍＶに達するまで定電流放電を行った。得られた放電容量から、次式３により急速放電効率を計算した。
急速放電効率（％）＝（第３サイクルにおける放電容量／第１サイクルにおける放 電容量）×１００ 式３ (Rapid discharge efficiency)
Subsequently, high-speed discharge was performed in the third cycle.
The current value was set to 13.5 mA, which is 15 times that of the first cycle, and constant current discharge was performed until the circuit voltage reached 2.5 mV. From the obtained discharge capacity, the rapid discharge efficiency was calculated by the following equation 3.
Rapid discharge efficiency (%) = (discharge capacity in third cycle / discharge capacity in first cycle) × 100 Equation 3

（サイクル特性）
別の評価電池を用いて、回路電圧が０ｍＶに達するまで４．０ｍＡの定電流充電を行った後、回路電圧が０ｍＶに達した時点で定電圧充電に切替え、さらに電流値が２０μＡになるまで充電を続けた後、１２０min 間休止した。次に４．０ｍＡの電流値で回路電圧が１．５Ｖに達するまで定電流放電を行い、この間の通電量から放電容量を求めた。この充放電を２０回繰返し、得られた放電容量から、次式４を用いてサイクル特性を計算した。
サイクル特性（％）＝（第２０サイクルにおける放電容量／第１サイクルにおける 放電容量）×１００ 式４ (Cycle characteristics)
Using another evaluation battery, constant current charging of 4.0 mA was performed until the circuit voltage reached 0 mV, and then switching to constant voltage charging was performed when the circuit voltage reached 0 mV, until the current value reached 20 μA. After charging was continued, the operation was stopped for 120 minutes. Next, constant current discharge was performed at a current value of 4.0 mA until the circuit voltage reached 1.5 V, and the discharge capacity was determined from the amount of current supplied during this time. This charge / discharge was repeated 20 times, and the cycle characteristics were calculated from the obtained discharge capacity using the following equation 4.
Cycle characteristics (%) = (discharge capacity in 20th cycle / discharge capacity in 1st cycle) × 100 Equation 4

（実施例２）
実施例１において、負極合剤ペーストＨ１（負極合剤Ｈ１）を調製する際の親水化された黒鉛質粒子Ａ１と複合黒鉛質炭素材料Ｄ１との質量比を７０：３０に変える以外は、実施例１と同様に負極合剤ペーストＨ２（負極合剤Ｈ２）の調製を行い、かつそれ以後の諸工程も実施例１と同様に実施して負極材料、負極および評価電池を作製し、電池特性などの評価も同様に行った。評価結果を表２に示した。 (Example 2)
Example 1 was repeated except that the mass ratio between the hydrophilized graphite particles A1 and the composite graphite carbon material D1 in preparing the negative electrode mixture paste H1 (negative electrode mixture H1) was changed to 70:30. A negative electrode mixture paste H2 (negative electrode mixture H2) was prepared in the same manner as in Example 1, and the subsequent steps were performed in the same manner as in Example 1 to produce a negative electrode material, a negative electrode, and an evaluation battery, and the battery characteristics Evaluation was also performed in the same manner. The evaluation results are shown in Table 2.

（実施例３）
実施例１において、複合黒鉛質炭素材料Ｄ１の黒鉛Ｂ１を黒鉛質粒子Ｂ２（KS44；Timcal（株）製、格子面間隔ｄ002 ０．３３５９ｎｍ、Ｒ値０．１０）に変えて作製した複合黒鉛質炭素材料Ｄ２（Ｒ値０．２９）を用いる以外は、実施例１と同様に負極合剤ペーストＨ３（負極合剤Ｈ３）の調製を行い、かつそれ以後の諸工程も実施例１と同様に実施して負極材料、負極および評価電池を作製し、電池特性などの評価も同様に行った。評価結果を表２に示した。 (Example 3)
Composite graphite prepared in Example 1 by changing the graphite B1 of the composite graphitic carbon material D1 to graphite particles B2 (KS44; manufactured by Timcal Co., Ltd., lattice spacing d 002 0.3359 nm, R value 0.10). A negative electrode mixture paste H3 (negative electrode mixture H3) was prepared in the same manner as in Example 1 except that the porous carbon material D2 (R value 0.29) was used, and the subsequent steps were the same as in Example 1. To produce a negative electrode material, a negative electrode, and an evaluation battery, and the battery characteristics and the like were evaluated in the same manner. The evaluation results are shown in Table 2.

（実施例４）
実施例１において、黒鉛質材料Ａ１の黒鉛質粒子としてメソフェーズ小球体（平均粒径：２５μｍ）を粉砕して平均粒径を１４μｍとしたメソフェーズ小球体を熱処理して作製した黒鉛質粒子Ｅ２を用いる以外は、実施例１と同様にメカノケミカル処理を行い親水化された黒鉛質粒子Ａ２を得、これを用いて実施例１と同様に負極合剤ペーストＨ４（負極合剤Ｈ４）の調製を行い、かつそれ以後の諸工程も実施例１と同様に実施して負極材料、負極および評価電池を作製し、電池特性などの評価も同様に行った。評価結果を表２に示した。 (Example 4)
In Example 1, graphite particles E2 produced by pulverizing mesophase small spheres (average particle size: 25 μm) and heat-treating mesophase small spheres having an average particle size of 14 μm are used as the graphite particles of the graphite material A1. Except for the above, a mechanochemical treatment was performed in the same manner as in Example 1 to obtain hydrophilic graphite particles A2, and a negative electrode mixture paste H4 (negative electrode mixture H4) was prepared using this in the same manner as in Example 1. The subsequent steps were performed in the same manner as in Example 1 to produce a negative electrode material, a negative electrode, and an evaluation battery, and the battery characteristics and the like were evaluated in the same manner. The evaluation results are shown in Table 2.

（実施例５）
実施例４のメソフェーズ小球体を熱処理して作製した黒鉛質粒子Ｅ２ １００質量部と、硬質微粒子Ｆとして無水シリカ（「AEROSIL 300 」：日本アエロジル（株）製、平均粒径７μｍ、硬さ相対値４．２）０．２質量部とを混合し、処理時間を２０min とする以外は、実施例１と同様にメカノケミカル処理を行ない親水化された黒鉛質粒子Ａ３を得た。平均粒径は１４μｍ、浸透量（親水性）は３．２ｇ（３０sec ）であった。
鱗片状天然黒鉛（平均粒径３０μｍ）を、カウンタジェットミル（200AFG；ホソカワミクロン（株）製）に入れ、空気圧力３００KPa で１時間機内循環させて造粒した。これから風力分級装置を用い、粒径５μｍ以下の微粉を除去し、さらに７５μｍの目開きのふるいを通して、平均粒径２０μｍの球状化黒鉛Ｂ３を得た。これの格子面間隔ｄ002 は０．３３５６ｎｍ、Ｒ値は０．８８、アスペクト比は２．０、比表面積は３．８m2/gであった。 (Example 5)
100 parts by mass of graphitic particles E2 produced by heat treatment of the mesophase microspheres of Example 4, and anhydrous silica ("AEROSIL 300", manufactured by Nippon Aerosil Co., Ltd., average particle size 7 μm, relative hardness value) as hard fine particles F 4.2) Mechanochemical treatment was carried out in the same manner as in Example 1 except that 0.2 parts by mass was mixed and the treatment time was set to 20 minutes to obtain hydrophilic graphite particles A3. The average particle size was 14 μm, and the permeation amount (hydrophilicity) was 3.2 g (30 sec).
Scaly natural graphite (average particle size: 30 μm) was placed in a counter jet mill (200 AFG; manufactured by Hosokawa Micron Corporation) and circulated in the machine at an air pressure of 300 KPa for 1 hour to granulate. From this, fine powder having a particle size of 5 μm or less was removed using an air classifier, and further passed through a 75 μm mesh sieve to obtain spheroidized graphite B3 having an average particle size of 20 μm. The lattice spacing d 002 was 0.3356 nm, the R value was 0.88, the aspect ratio was 2.0, and the specific surface area was 3.8 m 2 / g.

実施例４において、複合黒鉛質炭素材料Ｄ１の代わりに、該球状化黒鉛Ｂ３を用いて作製した複合黒鉛質炭素材料Ｄ３（Ｒ値０．３１）を用い、さらに親水化された黒鉛質材料Ａ３を用いる以外は、実施例４と同様に負極合剤ペーストＨ５（負極合剤Ｈ５）の調製を行い、かつそれ以後の諸工程も実施例４と同様に実施して負極材料、負極および評価電池を作製し、電池特性などの評価も同様に行った。評価結果を表２に示した。   In Example 4, instead of the composite graphitic carbon material D1, a composite graphitic carbon material D3 (R value 0.31) produced using the spheroidized graphite B3 was used, and the graphitic material A3 further hydrophilized. A negative electrode mixture paste H5 (negative electrode mixture H5) was prepared in the same manner as in Example 4 except that the negative electrode material, the negative electrode material, and the evaluation battery were used. Was prepared, and the battery characteristics and the like were evaluated in the same manner. The evaluation results are shown in Table 2.

（実施例６）
フェノール３９ｇと３７質量％ホルマリン水溶液６６ｇとヘキサメチレンテトラミン４ｇとからなる溶液に、実施例５の球状化黒鉛Ｂ３ １１０ｇを加え、分散状態で攪拌し、９０℃に加熱した。重縮合により得られた難黒鉛化性炭素前駆体であるフェノール樹脂Ｇ２が球状化黒鉛Ｂ３を被覆した複合黒鉛質炭素材料の前駆体を得た。ろ過により複合黒鉛質炭素材料の前駆体を分離した。被覆層は該フェノール樹脂Ｇ２分として２０質量％（残炭素分で１０質量％）であった。複合黒鉛質炭素材料の前駆体を空気中で２７０℃まで５時間かけて昇温し、さらに２７０℃に２時間保持し、被覆層を硬化させた。得られた該複合黒鉛質炭素材料Ｄ４を７５μｍふるい下になるように解砕した。ついで、窒素雰囲気中１０００℃で熱処理（炭化処理）を行い、さらに３０００℃で熱処理を行うことによって、該球状化黒鉛Ｂ３の表面の一部が難黒鉛化性炭素前駆体Ｇ２を熱処理して得られた炭素材料Ｃ２で被覆された複合黒鉛質炭素材料Ｄ４（Ｒ値０．１８）を得た。複合黒鉛質炭素材料Ｄ４中の炭素材料Ｃ２は１０質量％であった。 (Example 6)
110 g of the spheroidized graphite B3 of Example 5 was added to a solution consisting of 39 g of phenol, 66 g of a 37% by mass formalin aqueous solution and 4 g of hexamethylenetetramine, and the mixture was stirred in a dispersed state and heated to 90 ° C. A precursor of a composite graphitic carbon material in which a phenolic resin G2, which is a non-graphitizable carbon precursor obtained by polycondensation, was coated with spheroidized graphite B3. The precursor of the composite graphitic carbon material was separated by filtration. The coating layer was 20% by mass (10% by mass in terms of residual carbon content) of the phenol resin G2. The temperature of the precursor of the composite graphitic carbon material was raised to 270 ° C. in air over 5 hours, and the temperature was further maintained at 270 ° C. for 2 hours to cure the coating layer. The obtained composite graphitic carbon material D4 was crushed to be below a 75 μm sieve. Then, heat treatment (carbonization treatment) is performed at 1000 ° C. in a nitrogen atmosphere, and further heat treatment is performed at 3000 ° C., whereby a part of the surface of the spheroidized graphite B3 is obtained by heat treatment of the non-graphitizable carbon precursor G2. A composite graphitic carbon material D4 (R value 0.18) coated with the obtained carbon material C2 was obtained. The carbon material C2 in the composite graphitic carbon material D4 was 10% by mass.

実施例５において、複合黒鉛質炭素材料Ｄ３の代わりに、該複合黒鉛質炭素材料Ｄ４を用いる以外は、実施例５と同様に負極合剤ペーストＨ６（負極合剤Ｈ６）の調製を行い、かつそれ以後の諸工程も実施例１と同様に実施して負極材料、負極および評価電池を作製し、電池特性などの評価も同様に行った。評価結果を表２に示した。   In Example 5, a negative electrode mixture paste H6 (negative electrode mixture H6) was prepared in the same manner as in Example 5, except that the composite graphitic carbon material D4 was used instead of the composite graphitic carbon material D3. The subsequent steps were performed in the same manner as in Example 1 to prepare a negative electrode material, a negative electrode, and an evaluation battery, and the battery characteristics and the like were evaluated in the same manner. The evaluation results are shown in Table 2.

（比較例１）
実施例１において、メソフェーズ小球体の黒鉛質粒子Ｅ１（平均粒径：２５μｍ）のメカノケミカル処理を省略した黒鉛質粒子Ａ４（＝Ｅ１）を用いる以外は、実施例１と同様に負極合剤ペーストＨ７（負極合剤Ｈ７）の調製を行い、かつそれ以後の諸工程も実施例１と同様に実施して負極および評価電池を作製し、電池特性などの評価も同様に行った。評価結果を表２に示した。 (Comparative Example 1)
Negative electrode mixture paste in the same manner as in Example 1 except that mechanochemical treatment of mesophase microsphere graphite particles E1 (average particle size: 25 μm) was omitted. H7 (negative electrode mixture H7) was prepared, and the subsequent steps were carried out in the same manner as in Example 1 to prepare a negative electrode and an evaluation battery, and the battery characteristics and the like were evaluated in the same manner. The evaluation results are shown in Table 2.

（比較例２）
実施例１において、親水化された黒鉛質粒子Ａ１を用いることなく、実施例１と同様に負極材料ペーストＨ８（負極合剤Ｈ８）の調製を行い、かつそれ以後の諸工程も実施例１と同様に実施して負極および評価電池を作製し、電池特性などの評価も同様に行った。評価結果を表２に示した。 (Comparative Example 2)
In Example 1, a negative electrode material paste H8 (negative electrode mixture H8) was prepared in the same manner as in Example 1 without using the hydrophilic graphite particles A1, and the subsequent steps were the same as those in Example 1. A negative electrode and an evaluation battery were prepared in the same manner, and the battery characteristics and the like were evaluated in the same manner. The evaluation results are shown in Table 2.

実施例１〜６はいずれも、放電容量、初期充放電効率、急速充放電効率（レート特性）、およびサイクル特性に優れている。これ対して、親水化されていない黒鉛質粒子と複合黒鉛質炭素材料を用いる比較例１、および複合黒鉛質炭素材料のみを用いる比較例２は、初期充放電効率、急速充放電効率およびサイクル特性に劣っている。   All of Examples 1 to 6 are excellent in discharge capacity, initial charge / discharge efficiency, rapid charge / discharge efficiency (rate characteristics), and cycle characteristics. On the other hand, Comparative Example 1 using the non-hydrophilized graphite particles and the composite graphitic carbon material, and Comparative Example 2 using only the composite graphitic carbon material showed initial charge / discharge efficiency, rapid charge / discharge efficiency, and cycle characteristics. Inferior to

Figure 2004253379
Figure 2004253379

Figure 2004253379
Figure 2004253379

Figure 2004253379
Figure 2004253379

本発明のメカノケミカル処理に好適なメカノケミカル処理装置の構造を示す概略説明図である。It is a schematic explanatory view showing the structure of a mechanochemical processing device suitable for mechanochemical processing of the present invention. 実施例で用いたメカノケミカル処理装置の構造を示す概略説明図である。It is a schematic explanatory view showing the structure of the mechanochemical processing device used in the example. 負極材料の特性を評価するための評価電池の断面図である。FIG. 3 is a cross-sectional view of an evaluation battery for evaluating characteristics of a negative electrode material.

符号の説明Explanation of reference numerals

１１ 回転ドラム
１２ 内部部材（インナーピース）
１３ 被処理物
１４ 被処理物の循環機構
１５ 被処理物の排出機構
２１ 固定ドラム
２２ ローター
２３ 被処理物
２４ 被処理物の循環機構
２５ 被処理物の排出機構
２６ ブレード
２７ ステーター
２８ ジャケット
３１ 外装カップ
３２ 作用電極
３３ 外装缶
３４ 対極
３５ 電解質溶液含浸セパレータ
３６ 絶縁ガスケット
３７ａ、３７ｂ 集電体
11 rotating drum 12 internal member (inner piece)
13 Workpiece 14 Workpiece circulation mechanism 15 Workpiece discharge mechanism 21 Fixed drum 22 Rotor 23 Workpiece 24 Workpiece circulation mechanism 25 Workpiece discharge mechanism 26 Blade 27 Stator 28 Jacket
31 outer cup 32 working electrode 33 outer can 34 counter electrode 35 electrolyte solution impregnated separator 36 insulating gasket 37a, 37b current collector

Claims (8)

親水化された黒鉛質粒子Ａと、黒鉛Ｂの少なくとも一部に、低い結晶性の炭素材料Ｃの被覆を有する複合黒鉛質炭素材料Ｄとを含有し、前記複合黒鉛質炭素材料Ｄのアルゴンレーザーを用いたラマン分光法により測定された１３６０cm-1ピーク強度（ＩＤ）と１５８０cm-1ピーク強度（ＩＧ）の比ＩＤ／ＩＧが０．１以上０．３未満であることを特徴とするリチウムイオン二次電池用負極材料。 An argon laser of the graphitic carbon material D containing a hydrophilized graphitic particle A and a composite graphitic carbon material D having a coating of a low crystalline carbon material C on at least a part of the graphite B Lithium ion having a ratio of ID / IG between 1360 cm -1 peak intensity (ID) and 1580 cm -1 peak intensity (IG) measured by Raman spectroscopy with a ratio of 0.1 or more and less than 0.3 Anode material for secondary batteries. 前記親水化された黒鉛質粒子Ａが、メソフェーズ小球体またはその粉砕物を黒鉛化したのち、メカノケミカル処理により親水化してなる黒鉛質粒子Ａである請求項１に記載のリチウムイオン二次電池用負極材料。   2. The lithium ion secondary battery according to claim 1, wherein the hydrophilized graphitic particles A are graphitic particles A obtained by graphitizing a mesophase sphere or a pulverized product thereof and then hydrophilizing by mechanochemical treatment. 3. Negative electrode material. 前記複合黒鉛質炭素材料Ｄが、黒鉛Ｂに有機化合物Ｇを付着および／または含浸させた後、９００℃以上の温度で熱処理して得られた炭素材料Ｃの被覆を有する複合黒鉛質炭素材料Ｄである請求項１に記載のリチウムイオン二次電池用負極材料。   The composite graphitic carbon material D having a coating of a carbon material C obtained by adhering and / or impregnating the graphite B with the organic compound G and then heat-treating it at a temperature of 900 ° C. or higher. The negative electrode material for a lithium ion secondary battery according to claim 1, wherein 前記複合黒鉛質炭素材料Ｄが、黒鉛Ｂに有機化合物Ｇを付着および／または含浸させた後、９００℃以上２８００℃未満の温度で熱処理して得られた炭素材料Ｃの被覆を有する複合黒鉛質炭素材料Ｄである請求項３に記載のリチウムイオン二次電池用負極材料。   The composite graphitic carbon material D has a coating of a carbon material C obtained by adhering and / or impregnating the graphite B with the organic compound G and then performing a heat treatment at a temperature of 900 ° C. or more and less than 2800 ° C. The negative electrode material for a lithium ion secondary battery according to claim 3, which is carbon material D. 前記複合黒鉛質炭素材料Ｄが、黒鉛Ｂに難黒鉛化性炭素前駆体を付着および／または含浸させた後、２８００℃以上の温度で熱処理して得られた炭素材料Ｃの被覆を有する複合黒鉛質炭素材料Ｄである請求項１に記載のリチウムイオン二次電池用負極材料。   The composite graphitic carbon material D is a composite graphite having a carbon material C coating obtained by adhering and / or impregnating graphite B with a non-graphitizable carbon precursor and then heat-treating at a temperature of 2800 ° C. or higher. The negative electrode material for a lithium ion secondary battery according to claim 1, wherein the negative electrode material is a porous carbon material D. 請求項１〜５のいずれかに記載の前記複合黒鉛質炭素材料Ｄの平均粒径が１〜３０μｍである請求項１〜５のいずれか１項に記載のリウムイオン二次電池用負極材料。   The negative electrode material for a lithium ion secondary battery according to any one of claims 1 to 5, wherein the composite graphite carbon material D according to any one of claims 1 to 5 has an average particle size of 1 to 30 µm. 請求項１〜６のいずれか１項に記載のリチウムイオン二次電池用負極材料からなることを特徴とするリチウムイオン二次電池用負極。   A negative electrode for a lithium ion secondary battery, comprising the negative electrode material for a lithium ion secondary battery according to claim 1. 請求項７に記載のリチウムイオン二次電池用負極を用いることを特徴とするリチウムイオン二次電池。
A lithium ion secondary battery using the negative electrode for a lithium ion secondary battery according to claim 7.
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