JP7144625B2 - Spheroidized graphite, coated spheroidized graphite, negative electrode for lithium ion secondary battery and lithium secondary battery - Google Patents

Spheroidized graphite, coated spheroidized graphite, negative electrode for lithium ion secondary battery and lithium secondary battery Download PDF

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JP7144625B2
JP7144625B2 JP2021552677A JP2021552677A JP7144625B2 JP 7144625 B2 JP7144625 B2 JP 7144625B2 JP 2021552677 A JP2021552677 A JP 2021552677A JP 2021552677 A JP2021552677 A JP 2021552677A JP 7144625 B2 JP7144625 B2 JP 7144625B2
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遼太 山地
靖 間所
基治 小比賀
晃 松崎
弘之 増岡
幹人 須藤
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Description

本発明は、球状化黒鉛、被覆球状化黒鉛、リチウムイオン二次電池用負極およびリチウム二次電池に関する。 TECHNICAL FIELD The present invention relates to spheroidized graphite, coated spheroidized graphite, a negative electrode for a lithium ion secondary battery, and a lithium secondary battery.

リチウムイオン二次電池は、主な構成要素として、負極、正極および非水電解質を有する。リチウムイオンが、放電過程および充電過程で負極と正極との間を移動することにより、二次電池として作用する。
従来、リチウムイオン二次電池の負極材料として、球状化した黒鉛（球状化黒鉛）が使用される場合がある（特許文献１）。A lithium ion secondary battery has a negative electrode, a positive electrode, and a non-aqueous electrolyte as main components. Lithium ions move between the negative electrode and the positive electrode during discharging and charging processes, thereby acting as a secondary battery.
Conventionally, spheroidized graphite (spheroidized graphite) is sometimes used as a negative electrode material for lithium ion secondary batteries (Patent Document 1).

特開２０１４－１４６６０７号公報JP 2014-146607 A

リチウムイオン二次電池の負極材料には、出力特性に優れる（出力抵抗が小さい）ことが要求される場合がある。
とりわけ、リチウムイオン二次電池は、今後、自動車（ハイブリッド自動車、電気自動車など）に多く搭載されることが予想される。例えば自動車が急発進するときには、より優れた出力特性が要求される。A negative electrode material for a lithium ion secondary battery is sometimes required to have excellent output characteristics (low output resistance).
In particular, lithium-ion secondary batteries are expected to be widely used in automobiles (hybrid automobiles, electric automobiles, etc.) in the future. For example, when a car starts suddenly, better output characteristics are required.

そこで、本発明は、リチウムイオン二次電池の負極材料として用いた場合に出力特性に優れる球状化黒鉛を提供することを目的とする。 Accordingly, an object of the present invention is to provide spheroidized graphite that exhibits excellent output characteristics when used as a negative electrode material for a lithium ion secondary battery.

本発明者らは、鋭意検討した結果、下記構成を採用することにより、上記目的が達成されることを見出し、本発明を完成させた。 As a result of intensive studies, the inventors of the present invention have found that the above object can be achieved by adopting the following configuration, and completed the present invention.

すなわち、本発明は、以下の［１］～［９］を提供する。
［１］Ｘ線ＣＴを用いて得られる一次粒子の粒度分布において、球相当直径が０．８μｍ以下である一次粒子の体積比率が４０．０％以下であり、かつ、球相当直径が１．５μｍ以上３．０μｍ以下である一次粒子の体積比率が１３．０％以上である、球状化黒鉛。
［２］Ｘ線ＣＴを用いて得られる二次粒子の粒子形状分布において、球状である二次粒子の体積比率が１４．０％以上であり、かつ、棒状である二次粒子の体積比率が３４．０％以下である、上記［１］に記載の球状化黒鉛。
［３］平均二次粒子径が５．０μｍ以上１５．０μｍ以下であり、比表面積が５．０ｍ２／ｇ以上１５．０ｍ２／ｇ以下である、上記［１］または［２］に記載の球状化黒鉛。
［４］天然黒鉛を球状化してなる、上記［１］～［３］のいずれかに記載の球状化黒鉛。
［５］上記［１］～［４］のいずれかに記載の球状化黒鉛と、上記球状化黒鉛を被覆する炭素質と、を含有する被覆球状化黒鉛。
［６］平均二次粒子径が５．０μｍ以上５０．０μｍ以下であり、比表面積が０．５ｍ２／ｇ以上１０．０ｍ２／ｇ以下である、上記［５］に記載の被覆球状化黒鉛。
［７］細孔径が７．８ｎｍ以上３６．０ｎｍ以下の細孔に対応する細孔容積が、０．０１５ｃｍ３／ｇ以上０．０２８ｃｍ３／ｇ以下である、上記［５］または［６］に記載の被覆球状化黒鉛。
［８］上記［５］～［７］のいずれかに記載の被覆球状化黒鉛を含有する、リチウムイオン二次電池用負極。
［９］上記［８］に記載の負極を有する、リチウムイオン二次電池。That is, the present invention provides the following [1] to [9].
[1] In the particle size distribution of primary particles obtained using X-ray CT, the volume ratio of primary particles having an equivalent sphere diameter of 0.8 μm or less is 40.0% or less, and the equivalent sphere diameter is 1.0 μm or less. Spheroidized graphite in which the volume ratio of primary particles having a size of 5 μm or more and 3.0 μm or less is 13.0% or more.
[2] In the particle shape distribution of secondary particles obtained using X-ray CT, the volume ratio of spherical secondary particles is 14.0% or more, and the volume ratio of rod-shaped secondary particles is The spheroidized graphite according to the above [1], which is 34.0% or less.
[3] The above [1] or [2], wherein the average secondary particle size is 5.0 μm or more and 15.0 μm or less, and the specific surface area is 5.0 m 2 /g or more and 15.0 m 2 /g or less. spheroidized graphite.
[4] The spheroidized graphite according to any one of the above [1] to [3], which is obtained by spheroidizing natural graphite.
[5] Coated spheroidized graphite containing the spheroidized graphite according to any one of [1] to [4] above and a carbonaceous material coating the spheroidized graphite.
[6] The coated spheroidizer according to [5] above, which has an average secondary particle size of 5.0 μm or more and 50.0 μm or less and a specific surface area of 0.5 m 2 /g or more and 10.0 m 2 /g or less. graphite.
[7] The above [5] or [6], wherein the pore volume corresponding to pores having a pore diameter of 7.8 nm or more and 36.0 nm or less is 0.015 cm 3 /g or more and 0.028 cm 3 /g or less. The coated spheroidized graphite described in .
[8] A negative electrode for a lithium ion secondary battery, containing the coated spheroidized graphite according to any one of [5] to [7] above.
[9] A lithium ion secondary battery having the negative electrode according to [8] above.

本発明によれば、リチウムイオン二次電池の負極材料として用いた場合に出力特性に優れる球状化黒鉛を提供できる。 According to the present invention, it is possible to provide spheroidized graphite that exhibits excellent output characteristics when used as a negative electrode material for a lithium ion secondary battery.

球状粒子の３次元画像である。It is a three-dimensional image of spherical particles. 図１Ａとは異なる角度から観察された球状粒子の３次元画像である。1B is a three-dimensional image of spherical particles observed from an angle different from that of FIG. 1A. 図１Ａ～Ｂとは異なる角度から観察された球状粒子の３次元画像である。FIG. 1A-B is a three-dimensional image of spherical particles observed from different angles. 図１Ａ～Ｃとは異なる角度から観察された球状粒子の３次元画像である。1A-C are three-dimensional images of spherical particles observed from different angles. 棒状粒子の３次元画像である。It is a three-dimensional image of rod-shaped particles. 図２Ａとは異なる角度から観察された棒状粒子の３次元画像である。2B is a three-dimensional image of rod-shaped particles observed from an angle different from that of FIG. 2A. 図２Ａ～Ｂとは異なる角度から観察された棒状粒子の３次元画像である。2A-B are three-dimensional images of rod-shaped particles observed from different angles. 図２Ａ～Ｃとは異なる角度から観察された棒状粒子の３次元画像である。2A-C are three-dimensional images of rod-shaped particles observed from different angles. その他の二次粒子の３次元画像である。It is a three-dimensional image of other secondary particles. 図３Ａとは異なる角度から観察されたその他の二次粒子の３次元画像である。3B is a three-dimensional image of other secondary particles observed from an angle different from that of FIG. 3A. 図３Ａ～Ｂとは異なる角度から観察されたその他の二次粒子の３次元画像である。3A-B are three-dimensional images of other secondary particles observed from different angles. 図３Ａ～Ｃとは異なる角度から観察されたその他の二次粒子の３次元画像である。3A-C are three-dimensional images of other secondary particles observed from different angles. 実施例および比較例において電池特性を評価するために作製した評価電池の断面図である。FIG. 2 is a cross-sectional view of an evaluation battery prepared for evaluating battery characteristics in Examples and Comparative Examples.

［球状化黒鉛］
本発明の球状化黒鉛は、Ｘ線ＣＴを用いて得られる一次粒子の粒度分布において、球相当直径が０．８μｍ以下である一次粒子（以下、「微粒」ともいう）の体積比率が４０．０％以下であり、かつ、球相当直径が１．５μｍ以上３．０μｍ以下である一次粒子（以下、「粗粒」ともいう）の体積比率が１３．０％以上である。
本発明の球状化黒鉛を、リチウムイオン二次電池の負極材料として用いることにより、出力特性に優れる。これは、微粒および粗粒が上記割合となることで、リチウムイオンが出入りしやすくなるためと推測される。[Spheroidized graphite]
In the spheroidized graphite of the present invention, in the particle size distribution of primary particles obtained using X-ray CT, the volume ratio of primary particles having an equivalent spherical diameter of 0.8 μm or less (hereinafter also referred to as “fine particles”) is 40. 0% or less, and the volume ratio of primary particles having an equivalent spherical diameter of 1.5 μm or more and 3.0 μm or less (hereinafter also referred to as “coarse particles”) is 13.0% or more.
By using the spheroidized graphite of the present invention as a negative electrode material for a lithium ion secondary battery, the output characteristics are excellent. It is presumed that this is because lithium ions enter and exit easily when the ratio of fine grains and coarse grains is in the above range.

〈微粒および粗粒〉
上述したように、本発明の球状化黒鉛は、微粒の体積比率が４０．０％以下であり、かつ、粗粒の体積比率が１３．０％以上である。
出力特性がより優れるという理由から、微粒の体積比率は、３９．０％以下が好ましく、３４．０％以下がより好ましく、２８．０％以下が更に好ましく、２３．０％以下が特に好ましい。
一方、微粒の体積比率は、下限は特に限定されず、例えば、５．０％以上であり、１０．０％以上が好ましく、１３．０％以上がより好ましく、１５．０％以上が更に好ましい。〈Fine grains and coarse grains〉
As described above, the spheroidized graphite of the present invention has a volume ratio of fine particles of 40.0% or less and a volume ratio of coarse particles of 13.0% or more.
The volume ratio of the fine particles is preferably 39.0% or less, more preferably 34.0% or less, still more preferably 28.0% or less, and particularly preferably 23.0% or less, because the output characteristics are more excellent.
On the other hand, the lower limit of the volume ratio of fine particles is not particularly limited. .

出力特性がより優れるという理由から、粗粒の体積比率は、１４．０％以上が好ましく、１８．０％以上がより好ましく、２１．０％以上が更に好ましく、２５．０％以上が特に好ましい。
一方、粗粒の体積比率は、上限は特に限定されず、例えば、６０．０％以下であり、５０．０％以下が好ましく、４０．０％以下がより好ましく、３５．０％以下が更に好ましく、３２．０％以下が特に好ましい。The volume ratio of coarse particles is preferably 14.0% or more, more preferably 18.0% or more, still more preferably 21.0% or more, and particularly preferably 25.0% or more, because the output characteristics are more excellent. .
On the other hand, the upper limit of the volume ratio of coarse particles is not particularly limited. Preferably, 32.0% or less is particularly preferable.

《一次粒子の粒度分布》
球状化黒鉛を構成する一次粒子の粒度分布を求める方法を説明する。
一次粒子の大きさを把握するには、球状化黒鉛を非破壊および高分解能で可視化することを要する。そこで、放射光源を利用したＸ線ＣＴ（コンピュータ断層撮影）により、球状化黒鉛を観察する。より詳細には、ＳＰｒｉｎｇ－８のビームライン（ＢＬ２４ＸＵ）にて、結像型Ｘ線ＣＴを、以下の条件で実施する。
・Ｘ線エネルギー：８ｋｅＶ
・画像解像度：１２４８（Ｈ）×２０４８（Ｗ）ピクセル
・実行画素サイズ：６８ｎｍ／ピクセル
・露光時間：０．５秒
・投影像の撮影枚数：１２００枚
・Ｄｅｆｏｒｃｕｓ：０．３ｍｍ
試料である球状化黒鉛は、石英ガラスキャピラリ（内径：約０．１ｍｍ）に充填し、Ｘ線ＣＴに供する。
球状化黒鉛の投影像を撮影した後、断面スライス像に再構成する。次いで、市販の画像解析ソフトであるＥｘＦａｃｔ ＶＲ（日本ビジュアルサイエンス社製）のＷａｔｅｒｓｈｅｄ Ａｎａｌｙｓｉｓ機能を用いて、隣接する一次粒子どうしを分割して個別に認識し、各一次粒子の体積を算出する。更に、各一次粒子について、得られた体積から、球相当直径を求める。各一次粒子のデータをグラフ（横軸：球相当直径、縦軸：各一次粒子の総体積に対する体積比率）にプロットすることにより、一次粒子の粒度分布を求める。<<Particle size distribution of primary particles>>
A method for determining the particle size distribution of primary particles constituting the spheroidized graphite will be described.
To understand the size of the primary particles, non-destructive and high-resolution visualization of the spheroidized graphite is required. Therefore, spheroidized graphite is observed by X-ray CT (computed tomography) using a radiation light source. More specifically, an imaging X-ray CT is performed at the SPring-8 beamline (BL24XU) under the following conditions.
・X-ray energy: 8 keV
・Image resolution: 1248 (H) × 2048 (W) pixels ・Execution pixel size: 68 nm/pixel ・Exposure time: 0.5 seconds ・Number of shots of projection image: 1200 ・Deforce: 0.3 mm
The spheroidized graphite sample is filled in a quartz glass capillary (inner diameter: about 0.1 mm) and subjected to X-ray CT.
After capturing the projection image of the spheroidized graphite, it is reconstructed into a cross-sectional slice image. Next, using the Watershed Analysis function of ExFact VR (manufactured by Nippon Visual Science Co., Ltd.), which is commercially available image analysis software, adjacent primary particles are divided and recognized individually, and the volume of each primary particle is calculated. Further, for each primary particle, the equivalent sphere diameter is determined from the obtained volume. The particle size distribution of the primary particles is obtained by plotting the data of each primary particle on a graph (horizontal axis: equivalent sphere diameter, vertical axis: volume ratio of each primary particle to the total volume).

〈球状および棒状〉
本発明の球状化黒鉛は、出力特性がより優れるという理由から、Ｘ線ＣＴを用いて得られる二次粒子の粒子形状分布において、球状である二次粒子（以下、「球状粒子」ともいう）の体積比率が１４．０％以上であり、かつ、棒状である二次粒子（以下、「棒状粒子」ともいう）の体積比率が３４．０％以下であることが好ましい。〈Spherical and rod-shaped〉
The spheroidized graphite of the present invention has secondary particles that are spherical in the particle shape distribution of the secondary particles obtained by using X-ray CT (hereinafter also referred to as "spherical particles") because the output characteristics are superior. is 14.0% or more, and the volume ratio of rod-shaped secondary particles (hereinafter also referred to as "rod-shaped particles") is preferably 34.0% or less.

出力特性が更に優れるという理由から、球状粒子の体積比率は、１６．０％以上が好ましく、１８．０％以上がより好ましく、２０．０％以上が更に好ましい。
一方、球状粒子の体積比率は、上限は特に限定されず、例えば、５０．０％以下であり、４０．０％以下が好ましく、３０．０％以下がより好ましく、２５．０％以下が更に好ましく、２３．０％以下が特に好ましい。The volume ratio of the spherical particles is preferably 16.0% or more, more preferably 18.0% or more, and even more preferably 20.0% or more, because the output characteristics are further improved.
On the other hand, the upper limit of the volume ratio of the spherical particles is not particularly limited. Preferably, 23.0% or less is particularly preferable.

出力特性が更に優れるという理由から、棒状粒子の体積比率は、３０．０％以下が好ましく、２８．０％以下がより好ましく、２５．０％以下が更に好ましい。
一方、棒状粒子の体積比率は、下限は特に限定されず、例えば、５．０％以上であり、１０．０％以上が好ましく、１５．０％以上がより好ましく、２０．０％以上が更に好ましい。The volume ratio of the rod-shaped particles is preferably 30.0% or less, more preferably 28.0% or less, and even more preferably 25.0% or less, because the output characteristics are further improved.
On the other hand, the lower limit of the volume ratio of the rod-shaped particles is not particularly limited. preferable.

《二次粒子の粒子形状分布》
球状化黒鉛を構成する二次粒子の粒子形状分布を求める方法を説明する。
二次粒子の形状を把握するには、球状化黒鉛を非破壊および高分解能で可視化することを要する。そこで、放射光源を利用したＸ線ＣＴにより、球状化黒鉛を観察する。より詳細には、ＳＰｒｉｎｇ－８のビームライン（ＢＬ２４ＸＵ）にて、投影型Ｘ線ＣＴを、以下の条件で実施する。
・Ｘ線エネルギー：２０ｋｅＶ
・画像解像度：２０４８（Ｈ）×２０４８（Ｗ）ピクセル
・実行画素サイズ：３２５ｎｍ／ピクセル
・露光時間：０．１秒
・投影像の撮影枚数：１８００枚
・試料と検出器との間の距離：１０ｍｍ
試料である球状化黒鉛は、ボロシリケートガラスキャピラリ（内径：約０．６ｍｍ）に充填し、Ｘ線ＣＴに供する。
球状化黒鉛の投影像を撮影した後、断面スライス像に再構成する。次いで、市販の画像解析ソフトであるＥｘＦａｃｔ ＶＲ（日本ビジュアルサイエンス社製）のＷａｔｅｒｓｈｅｄ Ａｎａｌｙｓｉｓ機能を用いて、隣接する二次粒子どうしを分割して個別に認識し、各二次粒子の体積を算出する。
次に、各二次粒子について、互いに直交する慣性主軸を３軸設定し、それぞれの重心モーメントを求める。３つの重心モーメントのうち、最大のものをＬ、最小のものをＳ、中間のものをＭとする。以下の定義に従い、各二次粒子の粒子形状を、球状、棒状およびその他に分類する。
球状：Ｓ／Ｌ≧０．５、かつ、Ｍ／Ｌ≧０．５
棒状：Ｓ／Ｌ＜０．５、かつ、Ｍ／Ｌ＜０．５
各二次粒子の総体積に対する、球状に分類された二次粒子（球状粒子）の体積比率、および、棒状に分類された二次粒子（棒状粒子）の体積比率を求める。こうして、二次粒子の形状分布を求める。<<Particle shape distribution of secondary particles>>
A method for determining the particle shape distribution of secondary particles constituting the spheroidized graphite will be described.
Non-destructive and high-resolution visualization of spheroidized graphite is required to understand the shape of secondary particles. Therefore, spheroidized graphite is observed by X-ray CT using a radiant light source. More specifically, projection type X-ray CT is performed under the following conditions at the SPring-8 beamline (BL24XU).
・X-ray energy: 20 keV
・Image resolution: 2048 (H) × 2048 (W) pixels ・Effective pixel size: 325 nm/pixel ・Exposure time: 0.1 second ・Number of projection images: 1800 ・Distance between sample and detector: 10 mm
A sample of spheroidized graphite is filled in a borosilicate glass capillary (inner diameter: about 0.6 mm) and subjected to X-ray CT.
After capturing the projection image of the spheroidized graphite, it is reconstructed into a cross-sectional slice image. Next, using the Watershed Analysis function of ExFact VR (manufactured by Nippon Visual Science Co., Ltd.), which is a commercially available image analysis software, adjacent secondary particles are divided and recognized individually, and the volume of each secondary particle is calculated. .
Next, for each secondary particle, three mutually orthogonal principal axes of inertia are set, and the center-of-gravity moment of each is obtained. Of the three moments of the center of gravity, let L be the largest, S be the smallest, and M be the middle. The particle shape of each secondary particle is classified into spherical, rod-like and others according to the definitions below.
Spherical: S/L≧0.5 and M/L≧0.5
Rod-shaped: S/L<0.5 and M/L<0.5
A volume ratio of secondary particles classified into spheres (spherical particles) and a volume ratio of secondary particles classified into rods (rod-shaped particles) with respect to the total volume of each secondary particle are obtained. Thus, the shape distribution of secondary particles is obtained.

ここで、二次粒子のＸ線ＣＴデータを画像解析して得られる３次元画像の例を示す。
図１Ａ～Ｄは、球状粒子（Ｓ／Ｌ＝０．７９、Ｍ／Ｌ＝０．９１）の３次元画像である。
図２Ａ～Ｄは、棒状粒子（Ｓ／Ｌ＝０．１１、Ｍ／Ｌ＝０．１９）の３次元画像である。
図３Ａ～Ｄは、その他の二次粒子（楕円体状の粒子）（Ｓ／Ｌ＝０．２２、Ｍ／Ｌ＝０．８８）の３次元画像である。
図１Ａ～Ｄにおいては、同じ１つの二次粒子を観察しており、観察角度が、それぞれに異なる。これは、図２Ａ～Ｄおよび図３Ａ～Ｄにおいても同様である。Here, an example of a three-dimensional image obtained by image analysis of X-ray CT data of secondary particles is shown.
1A-D are three-dimensional images of spherical particles (S/L=0.79, M/L=0.91).
Figures 2A-D are three-dimensional images of rod-shaped particles (S/L = 0.11, M/L = 0.19).
3A to 3D are three-dimensional images of other secondary particles (ellipsoidal particles) (S/L=0.22, M/L=0.88).
In FIGS. 1A to 1D, the same single secondary particle is observed, and the observation angles are different. This is also the case in FIGS. 2A-D and 3A-D.

〈平均二次粒子径〉
本発明の球状化黒鉛の平均二次粒子径（単に「平均粒子径」ともいう）は、５．０μｍ以上が好ましく、６．５μｍ以上がより好ましく、７．０μｍ以上が更に好ましい。
一方、本発明の球状化黒鉛の平均粒子径は、１５．０μｍ以下が好ましく、１４．０μｍ以下がより好ましく、１２．０μｍ以下が更に好ましく、１０．０μｍ以下が特に好ましく、９．８μｍ以下が最も好ましい。
平均粒子径は、レーザー回折式粒度分布計（セイシン企業社製、ＬＭＳ２０００ｅ）を用いて求める粒度分布の累積度数が、体積百分率で５０％となる粒子径である。<Average secondary particle size>
The average secondary particle size (also simply referred to as “average particle size”) of the spheroidized graphite of the present invention is preferably 5.0 μm or more, more preferably 6.5 μm or more, and even more preferably 7.0 μm or more.
On the other hand, the average particle size of the spheroidized graphite of the present invention is preferably 15.0 μm or less, more preferably 14.0 μm or less, still more preferably 12.0 μm or less, particularly preferably 10.0 μm or less, and 9.8 μm or less. Most preferred.
The average particle size is the particle size at which the cumulative frequency of the particle size distribution obtained using a laser diffraction particle size distribution meter (LMS2000e, manufactured by Seishin Enterprise Co., Ltd.) is 50% in terms of volume percentage.

〈比表面積〉
本発明の球状化黒鉛の比表面積は、５．０ｍ２／ｇ以上が好ましく、７．０ｍ２／ｇ以上がより好ましく、９．５ｍ２／ｇ以上が更に好ましい。
一方、本発明の球状化黒鉛の比表面積は、１５．０ｍ２／ｇ以下が好ましく、１３．０ｍ２／ｇ以下がより好ましく、１１．０ｍ２／ｇ以下が更に好ましく、１０．０ｍ２／ｇ以下が特に好ましい。
比表面積は、ＪＩＳ Ｚ ８８３０：２０１３「ガス吸着による粉体（固体）の比表面積測定方法」に準拠して測定するＢＥＴ比表面積である。具体的には、試料を５０℃で予備乾燥し、次いで、３０分間窒素ガスを流した後、ＭＯＮＯＳＯＲＢ（カンタクローム・インスツルメンツ・ジャパン合同会社製）を用いて、窒素ガス吸着によるＢＥＴ１点法により求める。<Specific surface area>
The specific surface area of the spheroidized graphite of the present invention is preferably 5.0 m 2 /g or more, more preferably 7.0 m 2 /g or more, and even more preferably 9.5 m 2 /g or more.
On the other hand, the specific surface area of the spheroidized graphite of the present invention is preferably 15.0 m 2 /g or less, more preferably 13.0 m 2 /g or less, still more preferably 11.0 m 2 /g or less, and 10.0 m 2 /g. g or less is particularly preferred.
The specific surface area is the BET specific surface area measured according to JIS Z 8830:2013 "Method for measuring specific surface area of powder (solid) by gas adsorption". Specifically, the sample is pre-dried at 50 ° C., then nitrogen gas is flowed for 30 minutes, and then MONOSORB (manufactured by Quantachrome Instruments Japan LLC) is used to determine by the BET one-point method by nitrogen gas adsorption. .

［球状化黒鉛の製造方法］
本発明の球状化黒鉛を製造する方法としては、特に限定されないが、例えば、原料を球状に加工する方法が挙げられる。
ここで、原料は、球状（楕円体状を含む）以外の形状を有する黒鉛、例えば、鱗片状の黒鉛である。黒鉛は、天然黒鉛および人造黒鉛のどちらでもよいが、結晶性が高い等の理由から、天然黒鉛が好ましい。
より具体的には、例えば、接着剤や樹脂などの造粒助剤の共存下で原料を混合する方法；造粒助剤を用いずに原料に機械的外力を加える方法；両者を併用する方法；等が挙げられる。
これらのうち、造粒助剤を用いずに原料に機械的外力を加える方法が好ましい。以下、この方法を、より詳細に説明する。[Method for producing spheroidized graphite]
A method for producing the spheroidized graphite of the present invention is not particularly limited, but an example thereof includes a method of processing a raw material into spheres.
Here, the raw material is graphite having a shape other than a spherical shape (including an ellipsoidal shape), for example, flake graphite. Graphite may be either natural graphite or artificial graphite, but natural graphite is preferred because of its high crystallinity.
More specifically, for example, a method of mixing raw materials in the presence of a granulation aid such as an adhesive or a resin; a method of applying mechanical external force to the raw materials without using a granulation aid; a method of using both together. ; and the like.
Among these, the method of applying a mechanical external force to the raw material without using a granulation aid is preferred. This method is described in more detail below.

より詳細には、原料（例えば、鱗片状の黒鉛）を、粉砕装置を用いて機械的外力を加えることにより、粉砕および造粒する。こうして、原料を球状化して、球状化黒鉛を得る。
粉砕装置としては、例えば、回転ボールミル、カウンタジェットミル（ホソカワミクロン社製）、カレントジェット（日清エンジニアリング社製）、ハイブリダイゼーションシステム（奈良機械製作所社製）、ＣＦミル（宇部興産社製）、メカノフュージョンシステム（ホソカワミクロン社製）、シータコンポーザ（徳寿工作所社製）等が挙げられ、なかでも、ハイブリダイゼーションシステム（奈良機械製作所社製）が好ましい。More specifically, a raw material (for example, flake graphite) is pulverized and granulated by applying mechanical external force using a pulverizer. Thus, the raw material is spheroidized to obtain spheroidized graphite.
Examples of grinding equipment include rotary ball mill, counter jet mill (manufactured by Hosokawa Micron Corporation), current jet (manufactured by Nisshin Engineering Co., Ltd.), hybridization system (manufactured by Nara Machinery Co., Ltd.), CF mill (manufactured by Ube Industries), mechano Fusion System (manufactured by Hosokawa Micron), Theta Composer (manufactured by Tokuju Kosakusho) and the like can be mentioned, and among them, Hybridization System (manufactured by Nara Machinery Works) is preferable.

本発明においては、複数台の粉砕装置を直列に配置したうえで、これら複数台の粉砕装置を、原料が連続的に通過することが好ましい。すなわち、原料が１台の粉砕装置を通過した後、直ちに、次の粉砕装置で粉砕および造粒が行なわれるように、複数台の粉砕装置を直列に配置することが好ましい。 In the present invention, it is preferable that a plurality of pulverizers are arranged in series and the raw material continuously passes through these pulverizers. That is, it is preferable to arrange a plurality of pulverizing devices in series so that pulverization and granulation are performed in the next pulverizing device immediately after the raw material has passed through one pulverizing device.

このとき、粉砕装置の台数は、例えば２台以上であり、３台以上が好ましく、４台以上がより好ましく、５台以上が更に好ましく、６台以上が特に好ましい。
一方、粉砕装置の台数は、１０台以下が好ましく、８台以下がより好ましく、７台以下が更に好ましい。At this time, the number of pulverizing devices is, for example, 2 or more, preferably 3 or more, more preferably 4 or more, still more preferably 5 or more, and particularly preferably 6 or more.
On the other hand, the number of pulverizing devices is preferably 10 or less, more preferably 8 or less, and even more preferably 7 or less.

１台の粉砕装置において、原料を粉砕および造粒する時間（以下、「粉砕時間」ともいう）は、８分以上が好ましく、１３分以上がより好ましく、１８分以上が更に好ましい。
一方、１台の粉砕装置における粉砕時間は、６０分以下が好ましく、５０分以下がより好ましく、４０分以下が更に好ましい。In one pulverizer, the time for pulverizing and granulating the raw material (hereinafter also referred to as "pulverization time") is preferably 8 minutes or longer, more preferably 13 minutes or longer, and even more preferably 18 minutes or longer.
On the other hand, the pulverization time in one pulverizer is preferably 60 minutes or less, more preferably 50 minutes or less, and even more preferably 40 minutes or less.

粉砕装置の台数と、１台の粉砕装置における粉砕時間との積（以下、「合計粉砕時間」ともいう）は、３０分以上が好ましく、５０分以上がより好ましく、９０分以上が更に好ましい。
一方、合計粉砕時間は、１８０分以下が好ましく、１６０分以下がより好ましい。The product of the number of pulverizing devices and the pulverizing time in one pulverizing device (hereinafter also referred to as "total pulverizing time") is preferably 30 minutes or longer, more preferably 50 minutes or longer, and even more preferably 90 minutes or longer.
On the other hand, the total pulverization time is preferably 180 minutes or less, more preferably 160 minutes or less.

粉砕装置は、通常、ローターを内蔵する。
各粉砕装置におけるローターの周速度は、３０ｍ／秒以上が好ましく、４０ｍ／秒以上がより好ましく、６０ｍ／秒以上が更に好ましい。
一方、各粉砕装置におけるローターの周速度は、１００ｍ／秒以下が好ましく、８０ｍ／秒以下がより好ましい。The pulverizer usually incorporates a rotor.
The peripheral speed of the rotor in each pulverizing device is preferably 30 m/sec or more, more preferably 40 m/sec or more, and even more preferably 60 m/sec or more.
On the other hand, the peripheral speed of the rotor in each pulverizer is preferably 100 m/sec or less, more preferably 80 m/sec or less.

せん断力および圧縮力を原料に付与しやすくするために、各粉砕装置に充填する原料の量は、少ない方が好ましい。 In order to easily apply shearing force and compressive force to the raw material, it is preferable that the amount of the raw material to be filled in each pulverizing device is as small as possible.

［被覆球状化黒鉛］
本発明の被覆球状化黒鉛は、球状化黒鉛と、この球状化黒鉛を被覆する炭素質と、を含有する。そして、球状化黒鉛が、上述した本発明の球状化黒鉛である。[Coated spheroidized graphite]
The coated spheroidized graphite of the present invention contains spheroidized graphite and a carbonaceous material coating the spheroidized graphite. And the spheroidized graphite is the spheroidized graphite of the present invention described above.

〈炭素質の含有量〉
本発明の被覆球状化黒鉛における炭素質の含有量は、１．０質量％以上が好ましく、３．０質量％以上がより好ましく、８．０質量％以上が更に好ましく、１０．０質量％以上が特に好ましい。
炭素質の含有量がこの範囲であれば、球状化黒鉛の活性なエッヂ面が被覆されやすくなり、初期充放電効率が優れる。<Carbon content>
The carbonaceous content in the coated spheroidized graphite of the present invention is preferably 1.0% by mass or more, more preferably 3.0% by mass or more, still more preferably 8.0% by mass or more, and 10.0% by mass or more. is particularly preferred.
When the carbonaceous content is within this range, the active edge surfaces of the spheroidized graphite are easily covered, and the initial charge/discharge efficiency is excellent.

一方、本発明の被覆球状化黒鉛における炭素質の含有量は、３０．０質量％以下が好ましく、２５．０質量％以下がより好ましく、２０．０質量％以下が更に好ましく、１５．０質量％以下が特に好ましい。
炭素質の含有量がこの範囲であれば、相対的に放電容量の低い炭素質が少なくなり、放電容量が優れる。
また、炭素質の含有量がこの範囲である場合、後述する炭素質前駆体の使用量が少なくなるため、後述する混合および焼成の際に、融着が生じにくくなり、最終的に得られる炭素質の割れや剥離が抑制され、初期充放電効率が優れる。On the other hand, the carbonaceous content in the coated spheroidized graphite of the present invention is preferably 30.0% by mass or less, more preferably 25.0% by mass or less, even more preferably 20.0% by mass or less, and 15.0% by mass. % or less is particularly preferred.
If the content of carbonaceous matter is within this range, the amount of carbonaceous matter with relatively low discharge capacity is reduced, and the discharge capacity is excellent.
In addition, when the content of the carbonaceous matter is within this range, the amount of the carbonaceous precursor used as described later is reduced, so fusion is less likely to occur during mixing and firing described later, and the finally obtained carbon The cracking and peeling of the quality are suppressed, and the initial charge-discharge efficiency is excellent.

炭素質の含有量は、被覆球状化黒鉛の全体の平均値が上記範囲内であればよい。個々の被覆球状化黒鉛の全てが上記範囲内にある必要はなく、上記範囲以外の被覆球状化黒鉛を一部に含んでいてもよい。 As for the content of carbonaceous matter, the average value of the entire coated spheroidized graphite may be within the above range. It is not necessary for all individual coated spheroidized graphite to be within the above range, and a part of the coated spheroidized graphite may be included outside the above range.

炭素質の含有量は、球状化黒鉛と炭素質前駆体との混合物を焼成する際の条件と同じ条件で、炭素質前駆体のみを焼成し、その残炭量から求める。 The carbonaceous content is determined from the amount of residual carbon after firing only the carbonaceous precursor under the same conditions as in firing the mixture of spheroidized graphite and the carbonaceous precursor.

〈平均二次粒子径〉
本発明の被覆球状化黒鉛の平均二次粒子径（平均粒子径）は、５．０μｍ以上が好ましく、７．０μｍ以上がより好ましい。
一方、本発明の被覆球状化黒鉛の平均粒子径は、５０．０μｍ以下が好ましく、３０．０μｍ以下がより好ましく、２０．０μｍ以下が更に好ましい。<Average secondary particle size>
The average secondary particle size (average particle size) of the coated spheroidized graphite of the present invention is preferably 5.0 µm or more, more preferably 7.0 µm or more.
On the other hand, the average particle size of the coated spheroidized graphite of the present invention is preferably 50.0 μm or less, more preferably 30.0 μm or less, and even more preferably 20.0 μm or less.

〈比表面積〉
本発明の被覆球状化黒鉛の比表面積は、０．５ｍ２／ｇ以上が好ましく、１．５ｍ２／ｇ以上がより好ましく、３．０ｍ２／ｇ以上が更に好ましく、４．０ｍ２／ｇ以上が特に好ましい。
一方、本発明の被覆球状化黒鉛の比表面積は、１０．０ｍ２／ｇ以下が好ましく、８．０ｍ２／ｇ以下がより好ましく、７．０ｍ２／ｇ以下が更に好ましく、５．５ｍ２／ｇ以下が特に好ましい。<Specific surface area>
The specific surface area of the coated spheroidized graphite of the present invention is preferably 0.5 m 2 /g or more, more preferably 1.5 m 2 /g or more, still more preferably 3.0 m 2 /g or more, and 4.0 m 2 /g. The above are particularly preferred.
On the other hand, the specific surface area of the coated spheroidized graphite of the present invention is preferably 10.0 m 2 /g or less, more preferably 8.0 m 2 /g or less, still more preferably 7.0 m 2 /g or less, and 5.5 m 2 . / g or less is particularly preferred.

〈細孔容積〉
本発明者らは、被覆球状化黒鉛における、リチウムの吸蔵および放出に伴う抵抗と相関する指標として、窒素吸着等温線からＤＦＴ（Density Functional Theory）法により算出される細孔容積に注目した。
そのうえで、本発明者らは、細孔径が７．８ｎｍ未満の細孔に対応する細孔容積は非晶質炭素に由来し、リチウムの吸蔵および放出に伴う抵抗には寄与しにくいことを見出した。更に、本発明者らは、細孔径が７．８ｎｍ以上３６．０ｎｍ以下の細孔に対応する細孔容積が抵抗と相関する良い指標であることを明らかにした。<Pore volume>
The present inventors focused on the pore volume calculated by the DFT (Density Functional Theory) method from the nitrogen adsorption isotherm as an index that correlates with the resistance associated with lithium absorption and desorption in coated graphite.
In addition, the present inventors have found that the pore volume corresponding to pores with a pore diameter of less than 7.8 nm is derived from amorphous carbon and hardly contributes to the resistance associated with lithium absorption and release. . Furthermore, the present inventors have clarified that the pore volume corresponding to pores with a pore diameter of 7.8 nm or more and 36.0 nm or less is a good index that correlates with resistance.

具体的には、出力特性がより優れるという理由から、本発明の被覆球状化黒鉛において、細孔径が７．８ｎｍ以上３６．０ｎｍ以下の細孔に対応する細孔容積（以下、便宜的に「細孔容積Ｖ」ともいう）は、０．０１５ｃｍ３／ｇ以上が好ましく、０．０１６ｃｍ３／ｇ以上がより好ましい。
同様の理由から、本発明の被覆球状化黒鉛の細孔容積Ｖは、０．０２８ｃｍ３／ｇ以下が好ましく、０．０２６ｃｍ３／ｇ以下がより好ましく、０．０２３ｃｍ３／ｇ以下が更に好ましい。Specifically, in the coated spheroidized graphite of the present invention, the pore volume corresponding to pores having a pore diameter of 7.8 nm or more and 36.0 nm or less (hereinafter, for convenience, " The pore volume V”) is preferably 0.015 cm 3 /g or more, more preferably 0.016 cm 3 /g or more.
For the same reason, the pore volume V of the coated spheroidized graphite of the present invention is preferably 0.028 cm 3 /g or less, more preferably 0.026 cm 3 /g or less, and even more preferably 0.023 cm 3 /g or less. .

ＤＦＴ法による細孔容積の測定は、ＪＩＳ Ｚ ８８３１－２（ガス吸着によるメソ細孔及びマクロ細孔の測定方法）およびＪＩＳ Ｚ ８８３１－３（ガス吸着によるミクロ細孔の測定方法）に基づいて求める。このとき、相対圧５×１０－２Ｐａから、細孔容積の測定を開始する。Measurement of pore volume by DFT method is based on JIS Z 8831-2 (method for measuring mesopores and macropores by gas adsorption) and JIS Z 8831-3 (method for measuring micropores by gas adsorption). Ask. At this time, the measurement of the pore volume is started from a relative pressure of 5×10 −2 Pa.

［被覆球状化黒鉛の製造方法］
本発明の被覆球状化黒鉛を製造する方法としては、特に限定されないが、例えば、芯材である本発明の球状化黒鉛に、炭素質前駆体を加えて混合し、その後、焼成する方法が好適に挙げられる。この方法によれば、炭素質前駆体が、混合および焼成を経て、芯材（球状化黒鉛）を被覆する炭素質となる。すなわち、被覆球状化黒鉛が得られる。
以下、この方法を詳細に説明する。[Method for producing coated spheroidized graphite]
The method for producing the coated spheroidized graphite of the present invention is not particularly limited, but for example, a method of adding and mixing a carbonaceous precursor to the spheroidized graphite of the present invention, which is the core material, and then calcining the mixture is preferable. Listed in According to this method, the carbonaceous precursor becomes the carbonaceous material covering the core material (spheroidized graphite) through mixing and firing. That is, coated spheroidized graphite is obtained.
This method will be described in detail below.

〈炭素質前駆体〉
炭素質前駆体としては、黒鉛に比べて結晶性が低く、黒鉛化するために必要とされる高温処理をしても黒鉛結晶とはなりえない炭素材であるタールピッチ類および／または樹脂類が例示される。
タールピッチ類としては、例えば、コールタール、タール軽油、タール中油、タール重油、ナフタリン油、アントラセン油、コールタールピッチ、ピッチ油、メソフェーズピッチ、酸素架橋石油ピッチ、ヘビーオイルなどが挙げられる。
樹脂類としては、例えば、ポリビニルアルコール、ポリアクリル酸などの熱可塑性樹脂；フェノール樹脂、フラン樹脂などの熱硬化性樹脂；等が挙げられる。
コスト面の観点からは、炭素質前駆体は、樹脂類を含まず、タールピッチ類のみからなることが好ましい。このような炭素質前駆体として、例えば、コールタールピッチが８０質量％以上である炭素質前駆体が好適に挙げられる。<Carbonaceous precursor>
As carbonaceous precursors, tar pitches and/or resins, which are carbon materials that have lower crystallinity than graphite and do not become graphite crystals even when subjected to the high-temperature treatment required for graphitization. are exemplified.
Examples of tar pitches include coal tar, light tar oil, medium tar oil, heavy tar oil, naphthalene oil, anthracene oil, coal tar pitch, pitch oil, mesophase pitch, oxygen-crosslinked petroleum pitch, and heavy oil.
Examples of resins include thermoplastic resins such as polyvinyl alcohol and polyacrylic acid; thermosetting resins such as phenol resin and furan resin; and the like.
From the viewpoint of cost, it is preferable that the carbonaceous precursor does not contain resins and consists only of tar pitches. As such a carbonaceous precursor, for example, a carbonaceous precursor having a coal tar pitch of 80% by mass or more is suitable.

〈混合〉
芯材（球状化黒鉛）と炭素質前駆体とを混合する。混合比率は、最終的に得られる被覆球状化黒鉛において、炭素質が上述した含有量となる混合比率が好ましい。
混合の方法は、均質に混合できれば特に限定されず、公知の混合方法が用いられる。例えば、ヒーターや熱媒などの加熱機構を有する二軸式のニーダーなどを用いて加熱混合する方法が挙げられる。
混合する際の雰囲気は、特に限定されず、例えば、空気雰囲気である。
混合する際の温度（混合温度）は、５℃以上が好ましく、１０℃以上がより好ましく、２５℃以上が更に好ましい。一方、混合温度は、１５０℃以下が好ましく、１００℃以下がより好ましく、６０℃以下が更に好ましい。<mixture>
A core material (spheroidized graphite) and a carbonaceous precursor are mixed. The mixing ratio is preferably such that the finally obtained coated spheroidized graphite has the carbonaceous content described above.
The mixing method is not particularly limited as long as it can be mixed homogeneously, and a known mixing method is used. For example, a method of heating and mixing using a biaxial kneader having a heating mechanism such as a heater or a heat medium can be used.
The atmosphere during mixing is not particularly limited, and is, for example, an air atmosphere.
The temperature during mixing (mixing temperature) is preferably 5°C or higher, more preferably 10°C or higher, and even more preferably 25°C or higher. On the other hand, the mixing temperature is preferably 150° C. or lower, more preferably 100° C. or lower, and even more preferably 60° C. or lower.

〈焼成〉
上述した混合により得られる混合物を、焼成する。
焼成の方法は、特に限定されないが、焼成時の酸化を防ぐために不活性雰囲気下で焼成するのが好ましい。このとき、管状炉を使用することが好ましい。
焼成する際の雰囲気は、非酸化雰囲気として、アルゴン雰囲気、ヘリウム雰囲気、窒素雰囲気などが例示できる。
焼成する際の温度（焼成温度）は、７００℃以上が好ましく、９００℃以上がより好ましい。一方、焼成温度は、２０００℃以下が好ましく、１３００℃以下がより好ましく、１２００℃以下が更に好ましい。
具体的には、例えば、窒素気流中、７００℃以上２０００℃以下で焼成することが好ましい。
焼成時間は、５分以上が好ましい。一方、焼成時間は、３０時間以下が好ましい。
焼成温度まで昇温させる形態として、直線的な昇温、一定間隔で温度をホールドする段階的な昇温などの様々な形態を採ることができる。〈Firing〉
The mixture obtained by the above mixing is fired.
The firing method is not particularly limited, but firing in an inert atmosphere is preferred in order to prevent oxidation during firing. At this time, it is preferable to use a tubular furnace.
The atmosphere during firing can be exemplified by an argon atmosphere, a helium atmosphere, a nitrogen atmosphere, etc. as a non-oxidizing atmosphere.
The temperature (firing temperature) for firing is preferably 700° C. or higher, more preferably 900° C. or higher. On the other hand, the firing temperature is preferably 2000° C. or lower, more preferably 1300° C. or lower, and even more preferably 1200° C. or lower.
Specifically, for example, it is preferable to bake at 700° C. or higher and 2000° C. or lower in a nitrogen stream.
The baking time is preferably 5 minutes or longer. On the other hand, the firing time is preferably 30 hours or less.
Various modes such as a linear temperature increase and a stepwise temperature increase in which the temperature is held at regular intervals can be adopted as the mode for raising the temperature to the firing temperature.

本発明においては、焼成の後には、粉砕を行なわないことが好ましい。
また、焼成の前に、異種の黒鉛材料を、芯材（球状化黒鉛）に付着、埋設または複合させてもよい。異種の黒鉛材料としては、例えば、炭素質または黒鉛質の繊維；非晶質ハードカーボンなどの炭素質前駆体材料；有機材料；無機材料；等が挙げられる。In the present invention, pulverization is preferably not performed after firing.
Also, prior to firing, a different kind of graphite material may be adhered to, embedded in, or composited with the core material (spheroidized graphite). Heterogeneous graphite materials include, for example, carbonaceous or graphitic fibers; carbonaceous precursor materials such as amorphous hard carbon; organic materials; inorganic materials;

上述した「本発明の球状化黒鉛」および「本発明の被覆球状化黒鉛」を、以下、まとめて、「本発明の負極材料」と称する場合がある。 The above-described "spheroidized graphite of the present invention" and "coated spheroidized graphite of the present invention" may be hereinafter collectively referred to as "negative electrode material of the present invention".

［リチウムイオン二次電池用負極（負極）］
本発明のリチウムイオン二次電池用負極は、本発明の負極材料を含有するリチウムイオン二次電池用負極である。リチウムイオン二次電池用負極を単に「負極」ともいう。[Negative electrode for lithium ion secondary battery (negative electrode)]
The negative electrode for lithium ion secondary batteries of the present invention is a negative electrode for lithium ion secondary batteries containing the negative electrode material of the present invention. A negative electrode for a lithium ion secondary battery is also simply referred to as a “negative electrode”.

本発明の負極は、通常の負極に準じて作製される。
負極の作製時には、本発明の負極材料に結合剤を加えて予め調製した負極合剤を用いることが好ましい。負極合剤には、本発明の負極材料以外の活物質や導電材が含まれていてもよい。
結合剤としては、電解質に対して、化学的および電気化学的に安定性を示すものが好ましく、例えば、ポリテトラフルオロエチレン、ポリフッ化ビニリデンなどのフッ素系樹脂；ポリエチレン、ポリビニルアルコール、スチレンブタジエンゴムなどの樹脂；カルボキシメチルセルロース；等が用いられ、これらを２種以上併用することもできる。
結合剤は、通常、負極合剤の全量中の１～２０質量％程度の割合で用いられる。The negative electrode of the present invention is produced according to a normal negative electrode.
When producing the negative electrode, it is preferable to use a negative electrode mixture prepared in advance by adding a binder to the negative electrode material of the present invention. The negative electrode mixture may contain active materials and conductive materials other than the negative electrode material of the present invention.
As the binder, those exhibiting chemical and electrochemical stability with respect to the electrolyte are preferable, and examples thereof include fluorine-based resins such as polytetrafluoroethylene and polyvinylidene fluoride; polyethylene, polyvinyl alcohol, styrene-butadiene rubber, and the like. carboxymethyl cellulose; and the like, and two or more of these can be used in combination.
The binder is usually used in a ratio of about 1 to 20% by mass in the total amount of the negative electrode mixture.

より具体的には、まず、任意で、本発明の負極材料を分級などにより所望の粒度に調整する。その後、本発明の負極材料を結合剤と混合し、得られた混合物を溶剤に分散させて、ペースト状の負極合剤を調製する。溶剤としては、水、イソピロピルアルコール、Ｎ－メチルピロリドン、ジメチルホルムアミドなどが挙げられる。混合や分散には、公知の攪拌機、混合機、混練機、ニーダーなどが用いられる。 More specifically, first, optionally, the negative electrode material of the present invention is adjusted to a desired particle size by classification or the like. Thereafter, the negative electrode material of the present invention is mixed with a binder, and the resulting mixture is dispersed in a solvent to prepare a pasty negative electrode mixture. Examples of solvents include water, isopropyl alcohol, N-methylpyrrolidone, dimethylformamide and the like. For mixing and dispersion, known stirrers, mixers, kneaders, kneaders and the like are used.

調製したペーストを、集電体の片面または両面に塗布し、乾燥する。こうして、集電体に均一かつ強固に密着した負極合剤層（負極）が得られる。負極合剤層の厚さは、１０～２００μｍが好ましく、２０～１００μｍがより好ましい。
負極合剤層を形成した後、プレス加圧などの圧着を行なうことにより、負極合剤層（負極）と集電体との密着強度をより高めることができる。
集電体の形状は、特に限定されないが、例えば、箔状、メッシュ、エキスパンドメタルなどの網状などである。集電体の材質としては、銅、ステンレス、ニッケルなどが好ましい。集電体の厚さは、箔状の場合で５～２０μｍ程度が好ましい。The prepared paste is applied to one side or both sides of the current collector and dried. In this way, a negative electrode mixture layer (negative electrode) is obtained which is uniformly and strongly adhered to the current collector. The thickness of the negative electrode mixture layer is preferably 10 to 200 μm, more preferably 20 to 100 μm.
After the negative electrode mixture layer is formed, it is possible to further increase the adhesion strength between the negative electrode mixture layer (negative electrode) and the current collector by performing pressure bonding such as pressurization.
The shape of the current collector is not particularly limited, but may be, for example, a foil shape, a mesh, or a net shape such as expanded metal. Copper, stainless steel, nickel and the like are preferable as the material of the current collector. The thickness of the current collector is preferably about 5 to 20 μm in the case of foil.

〈配向度〉
本発明の負極は、高密度であっても、黒鉛の配向が抑えられていることが好ましい。負極の配向度は、Ｘ線回折によって定量的に評価できる。以下にその方法を説明する。
まず、２ｃｍ２の円盤状に打ち抜いた負極（密度：１．２０ｇ／ｃｍ３）を、ガラス板の上に、負極が上向きとなるように貼り付ける。このようにして作成した試料に、Ｘ線を照射し、回折させると、黒鉛の結晶面に対応する複数の回折ピークが現れる。複数の回折ピークのうち、（００４）面に由来する２θ＝５４．６°付近のピーク強度Ｉ００４と、（１１０）面に由来する２θ＝７７．４°付近のピーク強度Ｉ１１０との比（Ｉ００４／Ｉ１１０）を、負極の配向度とする。
負極の配向度が低いほど、充電時の負極の膨張率が小さく、非水電解質液の浸透性や流動性にも優れる。その結果、リチウムイオン二次電池の急速充電性、急速放電性、サイクル特性などの電池特性が良好となる。
具体的には、本発明の負極は、密度が１．２０ｇ／ｃｍ３である場合、配向度（Ｉ００４／Ｉ１１０）が５．０以下であることが好ましく、４．０以下がより好ましく、３．５以下が更に好ましい。<Orientation degree>
The negative electrode of the present invention preferably has suppressed graphite orientation even if it has a high density. The degree of orientation of the negative electrode can be quantitatively evaluated by X-ray diffraction. The method is described below.
First, a negative electrode (density: 1.20 g/cm 3 ) punched into a 2 cm 2 disc is pasted on a glass plate so that the negative electrode faces upward. When the sample thus prepared is irradiated with X-rays and diffracted, a plurality of diffraction peaks corresponding to the crystal planes of graphite appear. Among the multiple diffraction peaks, the ratio of the peak intensity I 004 near 2θ = 54.6 ° derived from the (004) plane and the peak intensity I 110 near 2θ = 77.4 ° derived from the (110) plane Let (I 004 /I 110 ) be the orientation of the negative electrode.
The lower the degree of orientation of the negative electrode, the smaller the expansion rate of the negative electrode during charging, and the better the permeability and fluidity of the non-aqueous electrolyte solution. As a result, battery characteristics such as rapid chargeability, rapid discharge characteristics, and cycle characteristics of the lithium ion secondary battery are improved.
Specifically, when the density of the negative electrode of the present invention is 1.20 g/cm 3 , the degree of orientation (I 004 /I 110 ) is preferably 5.0 or less, more preferably 4.0 or less. , 3.5 or less are more preferable.

［リチウムイオン二次電池］
本発明のリチウムイオン二次電池は、本発明の負極を有するリチウムイオン二次電池である。
本発明のリチウムイオン二次電池は、本発明の負極のほかに、更に、正極および非水電解質などを有する。本発明のリチウムイオン二次電池は、例えば、負極、非水電解質、正極の順で積層し、電池の外装材内に収容することにより構成される。
本発明のリチウムイオン二次電池は、用途、搭載機器、要求される充放電容量などに応じて、円筒型、角型、コイン型、ボタン型などの中から任意に選択できる。[Lithium ion secondary battery]
A lithium ion secondary battery of the present invention is a lithium ion secondary battery having the negative electrode of the present invention.
The lithium ion secondary battery of the present invention further has a positive electrode, a non-aqueous electrolyte and the like in addition to the negative electrode of the present invention. The lithium-ion secondary battery of the present invention is constructed, for example, by stacking a negative electrode, a non-aqueous electrolyte, and a positive electrode in this order and housing them in a battery exterior material.
The lithium-ion secondary battery of the present invention can be arbitrarily selected from cylindrical, square, coin, button, and the like, depending on the application, mounted equipment, required charge/discharge capacity, and the like.

〈正極〉
正極の材料（正極活物質）は、充分量のリチウムを吸蔵／離脱し得るものを選択するのが好ましい。正極活物質としては、リチウムのほか、例えば、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ＭＸＭｏ６Ｓ８－Ｙ（式中Ｍは少なくとも一種の遷移金属元素であり、Ｘは０≦Ｘ≦４、Ｙは０≦Ｙ≦１の範囲の数値である）で表されるシェブレル相化合物；活性炭；活性炭素繊維；等が挙げられる。バナジウム酸化物は、Ｖ２Ｏ５、Ｖ６Ｏ１３、Ｖ２Ｏ４、Ｖ３Ｏ８で示される。<Positive electrode>
It is preferable to select a material for the positive electrode (positive electrode active material) that can intercalate/deintercalate a sufficient amount of lithium. As the positive electrode active material, in addition to lithium, for example, lithium - containing compounds such as lithium - containing transition metal oxides, transition metal chalcogenides , vanadium oxides and lithium compounds thereof; M is at least one transition metal element, X is a numerical value in the range of 0 ≤ X ≤ 4, Y is a numerical value in the range of 0 ≤ Y ≤ 1) Chevrell phase compound; activated carbon; be done. Vanadium oxides are denoted by V 2 O 5 , V 6 O 13 , V 2 O 4 and V 3 O 8 .

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とを固溶したものであってもよい。複合酸化物は単独で使用しても、２種類以上を組み合わせて使用してもよい。
リチウム含有遷移金属酸化物は、具体的には、ＬｉＭ１ １－ＸＭ２ ＸＯ２（式中Ｍ１、Ｍ２は少なくとも一種の遷移金属元素であり、Ｘは０≦Ｘ≦１の範囲の数値である）、または、ＬｉＭ１ １－ＹＭ２ ＹＯ４（式中Ｍ１、Ｍ２は少なくとも一種の遷移金属元素であり、Ｙは０≦Ｙ≦１の範囲の数値である）で示される。
Ｍ１、Ｍ２で示される遷移金属元素は、Ｃｏ、Ｎｉ、Ｍｎ、Ｃｒ、Ｔｉ、Ｖ、Ｆｅ、Ｚｎ、Ａｌ、Ｉｎ、Ｓｎなどであり、好ましいのはＣｏ、Ｆｅ、Ｍｎ、Ｔｉ、Ｃｒ、Ｖ、Ａｌなどである。好ましい具体例は、ＬｉＣｏＯ２、ＬｉＮｉＯ２、ＬｉＭｎＯ２、ＬｉＮｉ０．９Ｃｏ０．１Ｏ２、ＬｉＮｉ０．５Ｃｏ０．５Ｏ２などである。
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、水酸化物、塩類等を出発原料とし、これら出発原料を所望の金属酸化物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。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. Composite oxides may be used alone or in combination of two or more.
Specifically, the lithium-containing transition metal oxide is LiM 1 1-X M 2 X O 2 (wherein M 1 and M 2 are at least one transition metal element, and X is in the range of 0≦X≦1 ), or LiM 1 1-Y M 2 Y O 4 (wherein M 1 and M 2 are at least one transition metal element, and Y is a numerical value in the range of 0≦Y≦1) is indicated by
The transition metal elements represented by M 1 and M 2 are Co, Ni, Mn, Cr, Ti, V, Fe, Zn, Al, In, Sn and the like, preferably Co, Fe, Mn, Ti, Cr , V, Al, and the like. Preferred specific examples are LiCoO 2 , LiNiO 2 , LiMnO 2 , LiNi 0.9 Co 0.1 O 2 , LiNi 0.5 Co 0.5 O 2 and the like.
Lithium-containing transition metal oxides are produced by, for example, using lithium, transition metal oxides, hydroxides, salts, etc. as starting materials, mixing these starting materials according to the composition of the desired metal oxide, and exposing to 600°C in an oxygen atmosphere. It can be obtained by firing at a temperature of ~1000°C.

正極活物質は、上述した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、正極中に炭酸リチウム等の炭素塩を添加できる。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できる。 As the positive electrode active material, the compounds described above may be used alone or in combination of two or more. For example, a carbon salt such as lithium carbonate can be added to the positive electrode. When forming the positive electrode, conventionally known various additives such as a conductive agent and a binder can be appropriately used.

正極は、例えば、正極活物質と、結合剤と、正極に導電性を付与するための導電剤とからなる正極合剤を、集電体の両面に塗布して正極合剤層を形成して作製される。
結合剤としては、負極の作製に使用される結合剤を使用できる。
導電剤としては、黒鉛化物、カーボンブラックなどの公知の導電剤が使用される。
集電体の形状は特に限定されないが、箔状または網状等が挙げられる。集電体の材質は、アルミニウム、ステンレス、ニッケル等である。集電体の厚さは、１０～４０μｍが好ましい。
正極も、負極と同様に、ペースト状の正極合剤を、集電体に塗布、乾燥し、その後、プレス加圧等の圧着を行なってもよい。The positive electrode is formed, for example, by applying a positive electrode mixture composed of a positive electrode active material, a binder, and a conductive agent for imparting conductivity to the positive electrode on both sides of the current collector to form a positive electrode mixture layer. produced.
As a binder, the binder used for making the negative electrode can be used.
As the conductive agent, known conductive agents such as graphite and carbon black are used.
The shape of the current collector is not particularly limited, but may be foil-like or net-like. The material of the current collector is aluminum, stainless steel, nickel, or the like. The thickness of the current collector is preferably 10 to 40 μm.
Similarly to the negative electrode, the positive electrode may be applied to a current collector with a paste-like positive electrode mixture, dried, and then pressure-bonded by pressing or the like.

〈非水電解質〉
非水電解質は液状の非水電解質（非水電解質液）としてもよく、固体電解質またはゲル電解質などの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二次電池として構成される。後者の場合、非水電解質電池は、高分子固体電解質、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。<Non-aqueous electrolyte>
The nonaqueous electrolyte may be a liquid nonaqueous electrolyte (nonaqueous electrolyte liquid), or may be a polymer electrolyte such as a solid electrolyte or a gel electrolyte.
In the former case, the nonaqueous electrolyte battery is configured as a so-called lithium ion secondary battery. In the latter case, the nonaqueous electrolyte battery is configured as a polymer electrolyte battery such as a solid polymer electrolyte battery or a polymer gel electrolyte battery.

非水電解質としては、通常の非水電解質液に使用される電解質塩である、ＬｉＰＦ６、ＬｉＢＦ４、ＬｉＡｓＦ６、ＬｉＣｌＯ４、ＬｉＢ（Ｃ６Ｈ５）、ＬｉＣｌ、ＬｉＢｒ、ＬｉＣＦ３ＳＯ３、ＬｉＣＨ３ＳＯ３、ＬｉＮ（ＣＦ３ＳＯ２）２、ＬｉＣ（ＣＦ３ＳＯ２）３、ＬｉＮ（ＣＦ３ＣＨ２ＯＳＯ２）２、ＬｉＮ（ＣＦ３ＣＦ２ＯＳＯ２）２、ＬｉＮ（ＨＣＦ２ＣＦ２ＣＨ２ＯＳＯ２）２、ＬｉＮ（（ＣＦ３）２ＣＨＯＳＯ２）２、ＬｉＢ［｛Ｃ６Ｈ３（ＣＦ３）２｝］４、ＬｉＡｌＣｌ４、ＬｉＳｉＦ６などのリチウム塩が用いられる。酸化安定性の点からは、ＬｉＰＦ６、ＬｉＢＦ４が好ましい。
非水電解質液中の電解質塩の濃度は、０．１～５．０ｍｏｌ／Ｌが好ましく、０．５～３．０ｍｏｌ／Ｌがより好ましい。As the non-aqueous electrolyte, LiPF 6 , LiBF 4 , LiAsF 6 , LiClO 4 , LiB(C 6 H 5 ), LiCl, LiBr, LiCF 3 SO 3 , which are electrolyte salts used in ordinary non-aqueous electrolyte solutions, LiCH3SO3 , LiN ( CF3SO2 ) 2 , LiC(CF3SO2)3 , LiN ( CF3CH2OSO2 ) 2 , LiN ( CF3CF2OSO2 ) 2 , LiN ( HCF2CF 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 and other lithium salts are used. From the viewpoint of oxidation stability, LiPF 6 and LiBF 4 are preferred.
The concentration of the electrolyte salt in the nonaqueous electrolyte liquid is preferably 0.1 to 5.0 mol/L, more preferably 0.5 to 3.0 mol/L.

非水電解質液を調製するための溶媒としては、例えば、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などのカーボネート；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、ジエチルエーテルなどのエーテル；スルホラン、メチルスルホランなどのチオエーテル；アセトニトリル、クロロニトリル、プロピオニトリルなどのニトリル；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；等が挙げられる。 Examples of solvents for preparing the non-aqueous electrolyte solution include carbonates such as ethylene carbonate, propylene carbonate, dimethyl carbonate and diethyl carbonate; 1,1- or 1,2-dimethoxyethane, 1,2-diethoxyethane, Ethers such as tetrahydrofuran, 2-methyltetrahydrofuran, γ-butyrolactone, 1,3-dioxolane, 4-methyl-1,3-dioxolane, anisole, diethyl ether; thioethers such as sulfolane and methylsulfolane; acetonitrile, chloronitrile, propio Nitriles such as nitrile; trimethyl borate, tetramethyl silicate, nitromethane, dimethylformamide, N-methylpyrrolidone, ethyl acetate, trimethyl orthoformate, nitrobenzene, benzoyl chloride, benzoyl bromide, tetrahydrothiophene, dimethyl sulfoxide, 3-methyl - aprotic organic solvents such as 2-oxazolidone, ethylene glycol, dimethylsulfite;

非水電解質を、固体電解質またはゲル電解質などの高分子電解質とする場合、マトリクスとして可塑剤（非水電解質液）でゲル化された高分子を用いることが好ましい。
マトリクスを構成する高分子としては、ポリエチレンオキサイド、その架橋体などのエーテル系高分子化合物；ポリ（メタ）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、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；等が好適に用いられる。
可塑剤である非水電解質液中の電解質塩の濃度は、０．１～５．０ｍｏｌ／Ｌが好ましく、０．５～２．０ｍｏｌ／Ｌがより好ましい。
高分子電解質において、可塑剤の割合は、１０～９０質量％が好ましく、３０～８０質量％がより好ましい。When the non-aqueous electrolyte is a polymer electrolyte such as a solid electrolyte or a gel electrolyte, it is preferable to use a polymer gelled with a plasticizer (non-aqueous electrolyte liquid) as the matrix.
Polymers constituting the matrix include ether-based polymer compounds such as polyethylene oxide and crosslinked products thereof; poly(meth)acrylate-based polymer compounds; polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, and the like. fluorine-based polymer compounds; and the like are preferably used.
The concentration of the electrolyte salt in the non-aqueous electrolyte liquid, which is the plasticizer, is preferably 0.1 to 5.0 mol/L, more preferably 0.5 to 2.0 mol/L.
In the polymer electrolyte, the proportion of the plasticizer is preferably 10-90% by mass, more preferably 30-80% by mass.

〈セパレータ〉
本発明のリチウムイオン二次電池においては、セパレータも使用できる。
セパレータは、その材質は特に限定されないが、例えば、織布、不織布、合成樹脂製微多孔膜などが用いられる。これらのうち、合成樹脂製微多孔膜が好ましく、なかでも、ポリオレフィン系微多孔膜が、厚さ、膜強度、膜抵抗の面でより好ましい。ポリオレフィン系微多孔膜としては、ポリエチレン製微多孔膜、ポリプロピレン製微多孔膜、これらを複合した微多孔膜などが好適に挙げられる。<Separator>
A separator can also be used in the lithium ion secondary battery of the present invention.
The material of the separator is not particularly limited. Among these, synthetic resin microporous membranes are preferred, and polyolefin microporous membranes are more preferred in terms of thickness, membrane strength, and membrane resistance. As the polyolefin-based microporous membrane, a polyethylene microporous membrane, a polypropylene microporous membrane, and a composite microporous membrane of these can be preferably mentioned.

以下に、実施例を挙げて本発明を具体的に説明する。ただし、本発明は、以下に説明する実施例に限定されない。 EXAMPLES The present invention will be specifically described below with reference to examples. However, the present invention is not limited to the examples described below.

〈実施例１〉
《球状化黒鉛の調製》
原料である鱗片状の天然黒鉛（平均粒子径：８μｍ）を、直列に配置された５台の粉砕装置（奈良機械製作所社製、ハイブリダイゼーションシステム）に連続的に通過させた。各粉砕装置において、粉砕時間は３０分、ローターの周速度は５０ｍ／秒とした。こうして、原料を、粉砕および造粒することにより、球状化黒鉛を得た。
得られた球状化黒鉛の各物性（微粒および粗粒の体積比率など）を、上述した方法により求めた。結果を下記表１に示す。<Example 1>
<<Preparation of spheroidized graphite>>
Scaly natural graphite (average particle size: 8 μm) as a raw material was continuously passed through five pulverizers (hybridization system manufactured by Nara Machinery Co., Ltd.) arranged in series. In each pulverizer, the pulverization time was 30 minutes and the peripheral speed of the rotor was 50 m/sec. Thus, spheroidized graphite was obtained by pulverizing and granulating the raw material.
Physical properties of the obtained spheroidized graphite (volume ratio of fine particles and coarse particles, etc.) were determined by the methods described above. The results are shown in Table 1 below.

《被覆球状化黒鉛の調製》
得られた球状化黒鉛に、炭素質前駆体であるコールタールピッチを加え、二軸ニーダーを用いて５０℃に加熱して３０分間混合した。炭素質前駆体は、最終的に得られる炭素質が下記表１に示す含有量となる量で加えた。その後、管状炉を用いて、窒素５Ｌ／ｍｉｎ流通下（非酸化性雰囲中）、１１００℃で１０時間焼成した。こうして、球状化黒鉛が炭素質で被覆された被覆球状化黒鉛を得た。
得られた被覆球状化黒鉛の各物性（平均二次粒子径など）を、上述した方法により求めた。結果を下記表１に示す。<<Preparation of coated spheroidized graphite>>
Coal tar pitch as a carbonaceous precursor was added to the obtained spheroidized graphite, and the mixture was heated to 50° C. and mixed for 30 minutes using a biaxial kneader. The carbonaceous precursor was added in such an amount that the carbonaceous matter finally obtained has the content shown in Table 1 below. After that, using a tubular furnace, sintering was performed at 1100° C. for 10 hours under nitrogen flow (in a non-oxidizing atmosphere) at 5 L/min. Thus, coated spheroidized graphite in which the spheroidized graphite was coated with carbonaceous matter was obtained.
Each physical property (average secondary particle size, etc.) of the obtained coated spheroidized graphite was obtained by the method described above. The results are shown in Table 1 below.

《負極の作製》
被覆球状化黒鉛（負極材料）９８質量部、カルボキシメチルセルロース（結合剤）１質量部およびスチレンブタジエンゴム（結合剤）１質量部を、水に入れ、攪拌することにより、負極合剤ペーストを調製した。
調製した負極合剤ペーストを、銅箔（厚さ：１６μｍ）の上に均一な厚さで塗布し、更に、真空中９０℃で乾燥し、負極合剤層を形成した。次に、この負極合剤層を、ハンドプレスによって１２０ＭＰａの圧力で加圧した。その後、銅箔および負極合剤層を、直径１５．５ｍｍの円形状に打ち抜いた。こうして、銅箔からなる集電体に密着した負極（厚さ：６０μｍ、密度：１．２０ｇ／ｃｍ３）を作製した。
なお、負極の作製と並行して、上述した方法に従い、負極の配向度を求めた。結果を下記表１に示す。<<Preparation of Negative Electrode>>
98 parts by mass of coated graphite (negative electrode material), 1 part by mass of carboxymethyl cellulose (binder), and 1 part by mass of styrene-butadiene rubber (binder) were added to water and stirred to prepare a negative electrode mixture paste. .
The prepared negative electrode mixture paste was applied to a copper foil (thickness: 16 μm) in a uniform thickness and dried in vacuum at 90° C. to form a negative electrode mixture layer. Next, this negative electrode mixture layer was pressurized with a hand press at a pressure of 120 MPa. After that, the copper foil and the negative electrode mixture layer were punched out into a circular shape with a diameter of 15.5 mm. In this way, a negative electrode (thickness: 60 μm, density: 1.20 g/cm 3 ) in close contact with a current collector made of copper foil was produced.
In addition, in parallel with the preparation of the negative electrode, the degree of orientation of the negative electrode was determined according to the method described above. The results are shown in Table 1 below.

《正極の作製》
リチウム金属箔をニッケルネットに押し付け、直径１５．５ｍｍの円形状に打ち抜いた。これにより、ニッケルネットからなる集電体に密着したリチウム金属箔（厚さ：０．５ｍｍ）からなる正極を作製した。<<Preparation of positive electrode>>
A lithium metal foil was pressed against a nickel net and punched into a circular shape with a diameter of 15.5 mm. Thus, a positive electrode made of a lithium metal foil (thickness: 0.5 mm) in close contact with a current collector made of nickel net was produced.

《評価電池の作製》
評価電池として、図４に示すボタン型二次電池を作製した。
図４は、ボタン型二次電池を示す断面図である。図４に示すボタン型二次電池は、外装カップ１と外装缶３との周縁部が絶縁ガスケット６を介してかしめられ、密閉構造が形成されている。密閉構造の内部には、外装缶３の内面から外装カップ１の内面に向けて順に、集電体７ａ、正極４、セパレータ５、負極２、および、集電体７ｂが積層されている。<<Preparation of evaluation battery>>
As an evaluation battery, a button-type secondary battery shown in FIG. 4 was produced.
FIG. 4 is a cross-sectional view showing a button type secondary battery. In the button-type secondary battery shown in FIG. 4, the outer cup 1 and the outer can 3 are crimped at their peripheral edges via an insulating gasket 6 to form a sealed structure. Inside the closed structure, a current collector 7a, a positive electrode 4, a separator 5, a negative electrode 2, and a current collector 7b are stacked in order from the inner surface of the outer can 3 toward the inner surface of the outer cup 1. FIG.

図４に示すボタン型二次電池を、次のように作製した。
まず、エチレンカーボネート（３３体積％）とメチルエチルカーボネート（６７体積％）との混合溶媒に、ＬｉＰＦ６を１ｍｏｌ／Ｌとなる濃度で溶解させることにより、非水電解質液を調製した。得られた非水電解質液を、ポリプロピレン多孔質体（厚さ：２０μｍ）に含浸させることにより、非水電解質液が含浸したセパレータ５を作製した。
次に、作製したセパレータ５を、銅箔からなる集電体７ｂに密着した負極２と、ニッケルネットからなる集電体７ａに密着した正極４との間に挟んで積層した。その後、集電体７ｂおよび負極２を外装カップ１の内部に収容し、集電体７ａおよび正極４を外装缶３の内部に収容し、外装カップ１と外装缶３とを合わせた。更に、外装カップ１と外装缶３との周縁部を、絶縁ガスケット６を介在させて、かしめて密閉した。このようにして、ボタン型二次電池を作製した。A button type secondary battery shown in FIG. 4 was produced as follows.
First, a non-aqueous electrolyte solution was prepared by dissolving LiPF 6 at a concentration of 1 mol/L in a mixed solvent of ethylene carbonate (33% by volume) and methyl ethyl carbonate (67% by volume). A polypropylene porous body (thickness: 20 μm) was impregnated with the obtained non-aqueous electrolyte solution to prepare a separator 5 impregnated with the non-aqueous electrolyte solution.
Next, the produced separator 5 was sandwiched and laminated between the negative electrode 2 in close contact with the current collector 7b made of copper foil and the positive electrode 4 in close contact with the current collector 7a made of nickel net. Thereafter, the current collector 7b and the negative electrode 2 were accommodated inside the outer cup 1, the current collector 7a and the positive electrode 4 were accommodated inside the outer can 3, and the outer cup 1 and the outer can 3 were put together. Furthermore, the outer cup 1 and the outer can 3 were crimped and hermetically sealed with an insulating gasket 6 interposed therebetween. Thus, a button-type secondary battery was produced.

作製したボタン型二次電池（評価電池）を用いて、以下に説明する充放電試験により、電池特性を評価した。結果を下記表１に示す。
以下の充放電試験においては、リチウムイオンを負極材料に吸蔵する過程を充電とし、負極材料からリチウムイオンが脱離する過程を放電とした。Using the produced button type secondary battery (evaluation battery), the battery characteristics were evaluated by the charge/discharge test described below. The results are shown in Table 1 below.
In the following charge/discharge test, the process of intercalating lithium ions into the negative electrode material was defined as charging, and the process of desorbing lithium ions from the negative electrode material was defined as discharging.

《充放電試験：放電容量および初期充放電効率》
まず、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なった。回路電圧が０ｍＶに達した時点で定電圧充電に切り替え、電流値が２０μＡになるまで充電を続けた。この間の通電量から、充電容量（単位：ｍＡｈ）を求めた。その後、１２０分間休止した。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なった。この間の通電量から、放電容量（単位：ｍＡｈ）を求めた。これを第１サイクルとした。
第１サイクルにおける充電容量と放電容量とから、次式に基づいて、初期充放電効率（単位：％）を求めた。結果を下記表１に示す。
初期充放電効率［％］＝（放電容量／充電容量）×１００《Charge-discharge test: Discharge capacity and initial charge-discharge efficiency》
First, constant current charging was performed at a current value of 0.9 mA until the circuit voltage reached 0 mV. When the circuit voltage reached 0 mV, it was switched to constant voltage charging, and charging was continued until the current value reached 20 μA. The charge capacity (unit: mAh) was obtained from the amount of electricity supplied during this period. Then rested for 120 minutes. Next, constant current discharge was performed at a current value of 0.9 mA until the circuit voltage reached 1.5V. A discharge capacity (unit: mAh) was obtained from the amount of electricity supplied during this period. This was designated as the first cycle.
From the charge capacity and discharge capacity in the first cycle, the initial charge/discharge efficiency (unit: %) was obtained based on the following formula. The results are shown in Table 1 below.
Initial charge/discharge efficiency [%] = (discharge capacity/charge capacity) x 100

《充放電試験：２５℃出力抵抗率》
２５℃の温度雰囲気下で、回路電圧が３．８２Ｖに達するまで１．０Ｃの定電流充電を行なった。その後、０℃の温度雰囲気に調整し、３時間休止した。
次に、０．５Ｃで１０秒間放電後、１０分間休止し、０．５Ｃで１０秒間充電後、１０分間休止した。
次に、１．０Ｃで１０秒間放電後、１０分間休止し、０．５Ｃで、２０秒でＳＯＣ（Ｓｔａｔｅ ｏｆ Ｃｈａｒｇｅ：充電率）５０％に充電を行ない、１０分間休止した。
次に、１．５Ｃで１０秒間放電後、１０分間休止し、０．５Ｃで、３０秒でＳＯＣ５０％に充電を行ない、１０分間休止した。
次に、２．０Ｃで１０秒間放電後、１０分間休止し、０．５Ｃで、４０秒でＳＯＣ５０％に充電を行ない、１０分間休止した。
試験後、上記で求めた放電容量（単位：ｍＡｈ）と、各Ｃレート（０．５Ｃ、１．０Ｃ、１．５Ｃ、２．０Ｃ）とを掛けて、電流値を算出した。また、そのＣレートで放電を行なった際の電圧（１０秒値）をそれぞれ求めた。
各Ｃレートでの結果を、電流値をｘ座標、電圧をｙ座標としてプロットし、それらの線形近似直線の傾きを最小二乗法から算出した。この傾きを出力抵抗（単位：Ω）とした。この値が小さいほど、出力特性に優れると評価できる。
更に、下記式から、各例（実施例および比較例）の２５℃出力抵抗率（単位：％）を求めた。結果を下記表１に示す。
２５℃出力抵抗率［％］＝（各例の出力抵抗／実施例１の出力抵抗）×１００<<Charging and discharging test: 25°C output resistivity>>
Under a temperature atmosphere of 25° C., constant current charging of 1.0 C was performed until the circuit voltage reached 3.82V. After that, the temperature atmosphere was adjusted to 0° C. and rested for 3 hours.
Next, the battery was discharged at 0.5C for 10 seconds, rested for 10 minutes, charged at 0.5C for 10 seconds, and rested for 10 minutes.
Next, the battery was discharged at 1.0C for 10 seconds, rested for 10 minutes, charged at 0.5C for 20 seconds to an SOC (State of Charge) of 50%, and rested for 10 minutes.
Next, the battery was discharged at 1.5C for 10 seconds, rested for 10 minutes, charged to SOC 50% at 0.5C in 30 seconds, and rested for 10 minutes.
Next, the battery was discharged at 2.0C for 10 seconds, rested for 10 minutes, charged to SOC 50% at 0.5C in 40 seconds, and rested for 10 minutes.
After the test, the discharge capacity (unit: mAh) obtained above was multiplied by each C rate (0.5C, 1.0C, 1.5C, 2.0C) to calculate the current value. Also, the voltage (value for 10 seconds) when the discharge was performed at the C rate was obtained.
The results at each C rate were plotted with the current value as the x-coordinate and the voltage as the y-coordinate, and the slope of the linear approximation straight line was calculated by the method of least squares. This slope was defined as the output resistance (unit: Ω). It can be evaluated that the smaller this value is, the better the output characteristics are.
Furthermore, the 25° C. output resistivity (unit: %) of each example (Example and Comparative Example) was obtained from the following formula. The results are shown in Table 1 below.
25° C. output resistivity [%]=(output resistance of each example/output resistance of Example 1)×100

〈実施例２〉
原料を通過させる粉砕装置の台数を７台とし、かつ、各粉砕装置において、粉砕時間を１５分、ローターの周速度を８０ｍ／秒とした。それ以外は、実施例１と同様にした。結果を下記表１に示す。<Example 2>
The number of pulverizing devices through which the raw material was passed was 7, and in each pulverizing device, the pulverization time was 15 minutes and the peripheral speed of the rotor was 80 m/sec. Otherwise, the procedure was the same as in Example 1. The results are shown in Table 1 below.

〈実施例３〉
原料を通過させる粉砕装置の台数を４台とし、かつ、各粉砕装置において、粉砕時間を１０分、ローターの周速度を６０ｍ／秒とした。それ以外は、実施例１と同様にした。結果を下記表１に示す。<Example 3>
The number of pulverizing devices through which the raw material was passed was 4, and in each pulverizing device, the pulverization time was 10 minutes and the peripheral speed of the rotor was 60 m/sec. Otherwise, the procedure was the same as in Example 1. The results are shown in Table 1 below.

〈実施例４〉
原料を通過させる粉砕装置の台数を４台とし、かつ、各粉砕装置において、粉砕時間を２０分、ローターの周速度を６０ｍ／秒とした。それ以外は、実施例１と同様にした。結果を下記表１に示す。<Example 4>
The number of pulverizing devices through which the raw material was passed was 4, and in each pulverizing device, the pulverization time was 20 minutes and the peripheral speed of the rotor was 60 m/sec. Otherwise, the procedure was the same as in Example 1. The results are shown in Table 1 below.

〈実施例５〉
原料を通過させる粉砕装置の台数を４台とし、かつ、各粉砕装置において、粉砕時間を２５分、ローターの周速度を６０ｍ／秒とした。それ以外は、実施例１と同様にした。結果を下記表１に示す。<Example 5>
The number of pulverizing devices through which the raw material was passed was four, and in each pulverizing device, the pulverization time was 25 minutes and the peripheral speed of the rotor was 60 m/sec. Otherwise, the procedure was the same as in Example 1. The results are shown in Table 1 below.

〈実施例６〉
原料を通過させる粉砕装置の台数を６台とし、かつ、各粉砕装置において、粉砕時間を２０分、ローターの周速度を６０ｍ／秒とした。それ以外は、実施例１と同様にした。結果を下記表１に示す。<Example 6>
The number of pulverizing devices through which the raw material was passed was 6, and in each pulverizing device, the pulverization time was 20 minutes and the peripheral speed of the rotor was 60 m/sec. Otherwise, the procedure was the same as in Example 1. The results are shown in Table 1 below.

〈比較例１〉
原料を通過させる粉砕装置の台数を４台とし、かつ、各粉砕装置において、粉砕時間を５分、ローターの周速度を３０ｍ／秒とした。それ以外は、実施例１と同様にした。結果を下記表１に示す。<Comparative Example 1>
The number of pulverizing devices through which the raw material was passed was 4, and in each pulverizing device, the pulverization time was 5 minutes and the peripheral speed of the rotor was 30 m/sec. Otherwise, the procedure was the same as in Example 1. The results are shown in Table 1 below.

〈比較例２〉
原料を通過させる粉砕装置の台数を１台とし、かつ、各粉砕装置において、粉砕時間を１０分、ローターの周速度を３０ｍ／秒とした。それ以外は、実施例１と同様にした。結果を下記表１に示す。<Comparative Example 2>
The number of pulverizing devices through which the raw material was passed was one, and in each pulverizing device, the pulverization time was 10 minutes and the peripheral speed of the rotor was 30 m/sec. Otherwise, the procedure was the same as in Example 1. The results are shown in Table 1 below.

〈比較例３〉
原料を通過させる粉砕装置の台数を４台とし、かつ、各粉砕装置において、粉砕時間を５分、ローターの周速度を５０ｍ／秒とした。それ以外は、実施例１と同様にした。結果を下記表１に示す。<Comparative Example 3>
The number of pulverizing devices through which the raw material was passed was 4, and in each pulverizing device, the pulverization time was 5 minutes and the peripheral speed of the rotor was 50 m/sec. Otherwise, the procedure was the same as in Example 1. The results are shown in Table 1 below.

〈比較例４〉
原料を通過させる粉砕装置の台数を９台とし、かつ、各粉砕装置において、粉砕時間を１０分、ローターの周速度を９０ｍ／秒とした。それ以外は、実施例１と同様にした。結果を下記表１に示す。<Comparative Example 4>
The number of pulverizers through which the raw material was passed was 9, and the pulverization time was 10 minutes and the peripheral speed of the rotor was 90 m/sec in each pulverizer. Otherwise, the procedure was the same as in Example 1. The results are shown in Table 1 below.

〈比較例５〉
原料を通過させる粉砕装置の台数を１０台とし、かつ、各粉砕装置において、粉砕時間を２０分、ローターの周速度を４０ｍ／秒とした。それ以外は、実施例１と同様にした。結果を下記表１に示す。<Comparative Example 5>
The number of pulverizing devices through which the raw material was passed was 10, and in each pulverizing device, the pulverization time was 20 minutes and the peripheral speed of the rotor was 40 m/sec. Otherwise, the procedure was the same as in Example 1. The results are shown in Table 1 below.

Figure 0007144625000001
Figure 0007144625000001

〈評価結果まとめ〉
上記表１に示すように、微粒の体積比率が４０％以下であり、かつ、粗粒の体積比率が１３％以上である実施例１～６は、これらの少なくともいずれかを満たさない比較例１～５よりも、出力特性が良好であった。<Summary of evaluation results>
As shown in Table 1 above, Examples 1 to 6 in which the volume ratio of fine particles is 40% or less and the volume ratio of coarse particles is 13% or more are Comparative Example 1 that does not satisfy at least one of these conditions. -5, the output characteristics were better.

１：外装カップ
２：負極
３：外装缶
４：正極
５：セパレータ
６：絶縁ガスケット
７ａ：集電体
７ｂ：集電体1: Outer cup 2: Negative electrode 3: Outer can 4: Positive electrode 5: Separator 6: Insulating gasket 7a: Current collector 7b: Current collector

Claims (7)

Ｘ線ＣＴを用いて得られる一次粒子の粒度分布において、球相当直径が０．８μｍ以下である一次粒子の体積比率が５．０％以上４０．０％以下であり、かつ、球相当直径が１．５μｍ以上３．０μｍ以下である一次粒子の体積比率が１３．０％以上６０．０％以下である、球状化黒鉛と、前記球状化黒鉛を被覆する炭素質と、を含有する被覆球状化黒鉛であって、
細孔径が７．８ｎｍ以上３６．０ｎｍ以下の細孔に対応する細孔容積が、０．０１５ｃｍ ３ ／ｇ以上０．０２８ｃｍ ３ ／ｇ以下である、被覆球状化黒鉛。 In the particle size distribution of primary particles obtained using X-ray CT, the volume ratio of primary particles having an equivalent sphere diameter of 0.8 μm or less is 5.0% or more and 40.0% or less, and the equivalent sphere diameter is A coated spherical body containing spheroidized graphite having a volume ratio of primary particles of 1.5 μm or more and 3.0 μm or less of 13.0% or more and 60.0% or less , and a carbonaceous material that coats the spheroidized graphite Graphite,
Coated spheroidized graphite , wherein a pore volume corresponding to pores having a pore diameter of 7.8 nm or more and 36.0 nm or less is 0.015 cm 3 /g or more and 0.028 cm 3 /g or less. 前記球状化黒鉛は、Ｘ線ＣＴを用いて得られる二次粒子の粒子形状分布において、球状である二次粒子の体積比率が１４．０％以上５０．０％以下であり、かつ、棒状である二次粒子の体積比率が５．０％以上３６．４％以下である、請求項１に記載の被覆球状化黒鉛。 The spheroidized graphite has a volume ratio of spherical secondary particles of 14.0% or more and 50.0% or less in the particle shape distribution of secondary particles obtained using X-ray CT, and is rod-shaped. 2. The coated spheroidized graphite according to claim 1, wherein the volume ratio of certain secondary particles is 5.0% or more and 36.4% or less . 平均二次粒子径が５．０μｍ以上５０．０μｍ以下であり、比表面積が０．５ｍ２／ｇ以上１０．０ｍ２／ｇ以下である、請求項１または２に記載の被覆球状化黒鉛。 The coated spheroidized graphite according to claim 1 or 2 , having an average secondary particle size of 5.0 µm or more and 50.0 µm or less and a specific surface area of 0.5 m 2 /g or more and 10.0 m 2 /g or less. Ｘ線ＣＴを用いて得られる一次粒子の粒度分布において、球相当直径が０．８μｍ以下である一次粒子の体積比率が５．０％以上４０．０％以下であり、かつ、球相当直径が１．５μｍ以上３．０μｍ以下である一次粒子の体積比率が１３．０％以上６０．０％以下であり、
Ｘ線ＣＴを用いて得られる二次粒子の粒子形状分布において、球状である二次粒子の体積比率が１４．０％以上５０．０％以下であり、かつ、棒状である二次粒子の体積比率が５．０％以上３６．４％以下である、球状化黒鉛と、前記球状化黒鉛を被覆する炭素質と、を含有する被覆球状化黒鉛であって、
平均二次粒子径が５．０μｍ以上５０．０μｍ以下であり、比表面積が４．０ｍ ２ ／ｇ以上１０．０ｍ ２ ／ｇ以下である、被覆球状化黒鉛。 In the particle size distribution of primary particles obtained using X-ray CT, the volume ratio of primary particles having an equivalent sphere diameter of 0.8 μm or less is 5.0% or more and 40.0% or less, and the equivalent sphere diameter is The volume ratio of primary particles having a size of 1.5 μm or more and 3.0 μm or less is 13.0% or more and 60.0% or less ,
In the particle shape distribution of secondary particles obtained using X-ray CT, the volume ratio of spherical secondary particles is 14.0% or more and 50.0% or less, and the volume of rod-shaped secondary particles Coated spheroidized graphite containing spheroidized graphite having a ratio of 5.0% or more and 36.4% or less and a carbonaceous material coating the spheroidized graphite,
Coated spheroidized graphite having an average secondary particle size of 5.0 μm or more and 50.0 μm or less and a specific surface area of 4.0 m 2 /g or more and 10.0 m 2 /g or less. 細孔径が７．８ｎｍ以上３６．０ｎｍ以下の細孔に対応する細孔容積が、０．０１５ｃｍ３／ｇ以上０．０２８ｃｍ３／ｇ以下である、請求項４に記載の被覆球状化黒鉛。 5. The coated spheroidized graphite according to claim 4 , wherein the pore volume corresponding to pores having a pore diameter of 7.8 nm or more and 36.0 nm or less is 0.015 cm 3 /g or more and 0.028 cm 3 /g or less. 請求項１～５のいずれか１項に記載の被覆球状化黒鉛を含有する、リチウムイオン二次電池用負極。 A negative electrode for a lithium ion secondary battery, containing the coated spheroidized graphite according to any one of claims 1 to 5 . 請求項６に記載の負極を有する、リチウムイオン二次電池。 A lithium ion secondary battery comprising the negative electrode according to claim 6 .
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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013209256A (en) 2012-03-30 2013-10-10 Mitsubishi Chemicals Corp Composite carbon material, method of manufacturing the same, and negative electrode and power storage device using the composite carbon material
JP2016105396A (en) 2014-11-19 2016-06-09 三菱化学株式会社 Carbon material for nonaqueous secondary battery, and nonaqueous secondary battery
JP2018133340A (en) 2013-01-29 2018-08-23 Ｊｆｅケミカル株式会社 Carbonaceous coated graphite particles, negative electrode for lithium ion secondary battery, and lithium ion secondary battery

Family Cites Families (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3364378B2 (en) * 1996-03-15 2003-01-08 株式会社東芝 Non-aqueous electrolyte secondary battery and method for manufacturing non-aqueous electrolyte secondary battery
CN201120305Y (en) * 2007-10-23 2008-09-24 湛江市新蓄能源科技有限公司 Full-automatic product line for producing spherical plumbago ultramicro powder body
JP5345907B2 (en) * 2009-08-10 2013-11-20 株式会社アーステクニカ Powder processing equipment and powder processing method
CN101905883B (en) * 2010-08-11 2013-01-02 黑龙江省牡丹江农垦奥宇石墨深加工有限公司 Production method of spherical graphite
US20130246219A1 (en) 2012-03-14 2013-09-19 Google Inc. Ranking and optimizing trips
JP2014022041A (en) * 2012-07-12 2014-02-03 Sony Corp Negative-electrode active material, manufacturing method thereof, lithium ion battery, battery pack, electronic device, electrically-powered vehicle, power storage device, and electric power system
JP2014151219A (en) * 2013-02-04 2014-08-25 Mitsubishi Chemicals Corp Powder treatment apparatus, sphere-shaped graphite particle produced by using the apparatus, negative electrode containing the sphere-shaped graphite particle for lithium ion secondary battery and lithium ion secondary battery provided with the negative electrode
JP2014152043A (en) * 2013-02-04 2014-08-25 Mitsubishi Chemicals Corp Spheronization treatment apparatus of graphite particle, sphere-shaped graphite spherically formed by treatment apparatus, negative electrode containing the sphere-shaped graphite for lithium ion secondary battery and lithium ion secondary battery provided with the negative electrode
KR20230134615A (en) * 2014-07-07 2023-09-21 미쯔비시 케미컬 주식회사 Carbon material, method for producing carbon material, and non-aqueous secondary battery using carbon material
KR101685832B1 (en) * 2014-07-29 2016-12-12 주식회사 엘지화학 Graphite secondary particles and lithium secondary battery comprising thereof
KR101817418B1 (en) * 2015-03-23 2018-01-11 주식회사 엘지화학 Negative electrode active material and method for preparing the same
JP7099325B2 (en) * 2016-11-22 2022-07-12 三菱ケミカル株式会社 Negative electrode material for non-aqueous secondary batteries, negative electrode for non-aqueous secondary batteries and non-aqueous secondary batteries
JP7067029B2 (en) * 2016-11-22 2022-05-16 三菱ケミカル株式会社 Negative electrode material for non-aqueous secondary batteries, negative electrode for non-aqueous secondary batteries and non-aqueous secondary batteries
JP6757704B2 (en) * 2017-08-31 2020-09-23 日本カーボン株式会社 Method for manufacturing negative electrode active material for lithium ion capacitors
CN107768669B (en) * 2017-10-13 2020-12-01 乌兰察布市大盛石墨新材料股份有限公司 Spherical graphite and preparation method thereof
KR102610410B1 (en) * 2017-12-22 2023-12-06 도까이 카본 가부시끼가이샤 Negative electrode material for lithium ion secondary battery and method of manufacturing negative electrode material for lithium ion secondary battery
WO2021033027A1 (en) * 2019-08-21 2021-02-25 Syrah Resources Limited Lithium-ion battery anode material based on spherical natural graphite containing silicates

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013209256A (en) 2012-03-30 2013-10-10 Mitsubishi Chemicals Corp Composite carbon material, method of manufacturing the same, and negative electrode and power storage device using the composite carbon material
JP2018133340A (en) 2013-01-29 2018-08-23 Ｊｆｅケミカル株式会社 Carbonaceous coated graphite particles, negative electrode for lithium ion secondary battery, and lithium ion secondary battery
JP2016105396A (en) 2014-11-19 2016-06-09 三菱化学株式会社 Carbon material for nonaqueous secondary battery, and nonaqueous secondary battery

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