JP2009181827A - Method of manufacturing negative electrode for lithium-ion battery, and lithium-ion battery - Google Patents

Method of manufacturing negative electrode for lithium-ion battery, and lithium-ion battery Download PDF

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JP2009181827A
JP2009181827A JP2008020313A JP2008020313A JP2009181827A JP 2009181827 A JP2009181827 A JP 2009181827A JP 2008020313 A JP2008020313 A JP 2008020313A JP 2008020313 A JP2008020313 A JP 2008020313A JP 2009181827 A JP2009181827 A JP 2009181827A
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ion battery
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lithium
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Rika Sato
里佳 佐藤
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Bridgestone 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 method of manufacturing a negative electrode for a lithium-ion battery having sufficient charge/discharge capacity and superior high speed charge/discharge characteristics. <P>SOLUTION: The method of manufacturing the negative electrode for the lithium-ion battery includes (i) a step in which a compound with an aromatic ring is electrolytic oxidation-polymerized to form a fibril-like polymer on a conductive substrate 1, (ii) a step in which the fibril-like polymer is calcined to form a carbon fiber 2 on the conductive substrate 1, (iii) a step in which the carbon fiber 2 is covered with conductive metal 3, (iv) a step in which metal 4 capable of storing/releasing lithium is carried on the conductive metal 3, and (v) a step in which heat treatment is performed in a temperature range of 200 to 900°C in vacuum. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

本発明は、リチウムイオン電池用負極の製造方法及び該方法で製造された負極を具えるリチウムイオン電池に関し、特には、充放電容量が高く、高速充放電特性に優れたリチウムイオン電池に関するものである。   The present invention relates to a method for producing a negative electrode for a lithium ion battery and a lithium ion battery comprising the negative electrode produced by the method, and particularly relates to a lithium ion battery having a high charge / discharge capacity and excellent high-speed charge / discharge characteristics. is there.

昨今、携帯用端末やモバイル通信機器として、リチウムイオン電池が広く普及している。該リチウムイオン電池は、現存する二次電池の中でも最もエネルギー密度が高いため、該リチウムイオン電池をハイブリッド自動車や燃料電池自動車の補助電源として、あるいは定置用大型電源として使用することも検討されている。   Recently, lithium ion batteries are widely used as portable terminals and mobile communication devices. Since the lithium ion battery has the highest energy density among the existing secondary batteries, it is considered to use the lithium ion battery as an auxiliary power source for a hybrid vehicle or a fuel cell vehicle or as a large power source for stationary use. .

上記リチウムイオン電池は、リチウムイオンを電気化学的に吸蔵・離脱可能な層状構造の正極（例えば、ＬｉＣｏＯ2）と同特性を有する負極（例えば、黒鉛）がリチウムイオンを溶解した電解液を介して対向した構造を有する電池であり、一般に、正極と負極との短絡を防止するために電解液を透過しうる多孔質ポリマー膜が両極材の間に配置された構造を有している。 The lithium ion battery includes a negative electrode (for example, graphite) having the same characteristics as a positive electrode (for example, LiCoO 2 ) having a layered structure capable of electrochemically inserting and extracting lithium ions via an electrolytic solution in which lithium ions are dissolved. A battery having a structure opposite to each other, and generally has a structure in which a porous polymer film capable of permeating an electrolytic solution is disposed between both electrodes in order to prevent a short circuit between a positive electrode and a negative electrode.

そして、現在、高速充放電用途のリチウムイオン電池の負極としては、メソフェーズカーボンマイクロビーズ（ＭＣＭＢ）等のソフトカーボンにＶＧＣＦ等のファイバー状カーボンを添加して調製したペーストを銅箔に塗布して形成した電極や、ハードカーボンからなるペーストを銅箔に塗布して形成した電極が使用されている。しかしながら、いずれの電極も、低速充電高速放電での性能は一定のレベルに達しているものの、高速充放電特性については依然として改良の余地が大きい。   Currently, the negative electrode of lithium ion batteries for high-speed charge / discharge applications is formed by applying a paste prepared by adding fiber carbon such as VGCF to soft carbon such as mesophase carbon microbeads (MCMB) to copper foil. And electrodes formed by applying a paste made of hard carbon on a copper foil are used. However, although all of the electrodes have reached a certain level of performance in low-speed charge and high-speed discharge, there is still much room for improvement in the high-speed charge / discharge characteristics.

また、高容量な負極活物質として金属スズ等が知られているが、金属スズ等を負極に使用したリチウムイオン電池は、初期不可逆容量が大きく、充放電に伴う不可逆な体積膨張によって、微粉化や集電性の低下等の問題があるため、実用化が困難である。   Also, metal tin is known as a high capacity negative electrode active material, but lithium ion batteries using metal tin as the negative electrode have a large initial irreversible capacity and are pulverized due to irreversible volume expansion associated with charge and discharge. It is difficult to put it into practical use because of problems such as low current collection and current collection.

これに対して、本発明者らは、（１）特定の方法で作製した３次元連続状炭素繊維自体を活物質とした電極（特開２００７−１６５２８５号参照）や、（２）該３次元連続状炭素繊維に金属微粒子を担持した電極（特開２００７−０４２６０１号参照）等を開発してきたが、（１）の電極は、高速充放電特性に優れるものの、容量自体が不十分であり、一方、（２）の電極は、容量及び高速充放電特性の双方が向上しているものの、未だ要求レベルを満足できていない。   In contrast, the present inventors have (1) an electrode using a three-dimensional continuous carbon fiber itself produced by a specific method (see Japanese Patent Application Laid-Open No. 2007-165285), and (2) the three-dimensional An electrode in which metal fine particles are supported on a continuous carbon fiber (see Japanese Patent Application Laid-Open No. 2007-042601) and the like have been developed. On the other hand, although the electrode of (2) has improved both capacity and high-speed charge / discharge characteristics, it still does not satisfy the required level.

特開２００７−１６５２８５号公報JP 2007-165285 A 特開２００７−０４２６０１号公報JP 2007-042601 A

そこで、本発明の目的は、上記の問題を解決し、充放電容量が高く、高速充放電特性に優れたリチウムイオン電池用負極の製造方法、並びに該方法で製造された負極を具えたリチウムイオン電池を提供することにある。   Accordingly, an object of the present invention is to solve the above-mentioned problems, to provide a method for producing a negative electrode for a lithium ion battery having high charge / discharge capacity and excellent high-speed charge / discharge characteristics, and lithium ion comprising a negative electrode produced by the method. To provide a battery.

本発明者は、上記目的を達成するために鋭意検討した結果、導電性基板上において芳香環を有する化合物を電解酸化重合してフィブリル状ポリマーを生成させ、該フィブリル状ポリマーを焼成して炭素繊維を形成し、該炭素繊維を導電性金属で被覆し、該導電性金属上にリチウムを吸蔵・脱離可能な金属を担持した後、更に、熱処理を施して作製した電極をリチウムイオン電池の負極として使用することで、充放電容量が高く、高速充放電特性に優れたリチウムイオン電池が得られることを見出し、本発明を完成させるに至った。   As a result of diligent investigations to achieve the above object, the present inventors have produced a fibril polymer by electrolytic oxidation polymerization of a compound having an aromatic ring on a conductive substrate, and the fibril polymer is baked to obtain carbon fibers. The carbon fiber is coated with a conductive metal, and a metal capable of inserting and extracting lithium is supported on the conductive metal, and further subjected to heat treatment to form a negative electrode for a lithium ion battery. As a result, it was found that a lithium ion battery having a high charge / discharge capacity and excellent high-speed charge / discharge characteristics was obtained, and the present invention was completed.

即ち、本発明のリチウムイオン電池用負極の製造方法は、導電性基板と、該導電性基板上に形成された炭素繊維と、該炭素繊維を被覆する導電性金属と、該導電性金属上に担持されたリチウムを吸蔵・脱離可能な金属とからなるリチウムイオン電池用負極の製造方法であって、
(i)導電性基板上において、芳香環を有する化合物を電解酸化重合してフィブリル状ポリマーを生成させる工程と、
(ii)該フィブリル状ポリマーを焼成して導電性基板上に炭素繊維を生成させる工程と、
(iii)該炭素繊維を導電性金属で被覆する工程と、
(iv)該導電性金属上にリチウムを吸蔵・脱離可能な金属を担持する工程と、
(v)真空中、200〜900℃で熱処理を行う工程と
を含むことを特徴とする。 That is, the method for producing a negative electrode for a lithium ion battery according to the present invention comprises a conductive substrate, a carbon fiber formed on the conductive substrate, a conductive metal covering the carbon fiber, and the conductive metal. A method for producing a negative electrode for a lithium ion battery comprising a metal capable of occluding and desorbing supported lithium,
(i) a step of electrolytically oxidatively polymerizing a compound having an aromatic ring on a conductive substrate to produce a fibrillated polymer;
(ii) firing the fibrillated polymer to form carbon fibers on a conductive substrate;
(iii) coating the carbon fiber with a conductive metal;
(iv) carrying a metal capable of inserting and extracting lithium on the conductive metal;
and (v) performing a heat treatment at 200 to 900 ° C. in a vacuum.

本発明のリチウムイオン電池用負極の製造方法の好適例においては、前記熱処理工程(v)を3 hPa以下の真空下で8〜24時間行う。   In a preferred example of the method for producing a negative electrode for a lithium ion battery of the present invention, the heat treatment step (v) is performed under a vacuum of 3 hPa or less for 8 to 24 hours.

本発明のリチウムイオン電池用負極の製造方法の他の好適例においては、前記炭素繊維を被覆する導電性金属がＣｕである。   In another preferred embodiment of the method for producing a negative electrode for a lithium ion battery of the present invention, the conductive metal covering the carbon fiber is Cu.

本発明のリチウムイオン電池用負極の製造方法の他の好適例においては、前記リチウムを吸蔵・脱離可能な金属がＳｎである。   In another preferred embodiment of the method for producing a negative electrode for a lithium ion battery of the present invention, the metal capable of inserting and extracting lithium is Sn.

また、本発明のリチウムイオン電池は、上記の方法で製造したリチウムイオン電池用負極を具えることを特徴とする。   Moreover, the lithium ion battery of the present invention is characterized by comprising a negative electrode for a lithium ion battery produced by the above method.

本発明によれば、導電性基板上において芳香環を有する化合物を電解酸化重合してフィブリル状ポリマーを生成させ、該フィブリル状ポリマーを焼成して炭素繊維を形成し、該炭素繊維を導電性金属で被覆し、該導電性金属上にリチウムを吸蔵・脱離可能な金属を担持した後、更に、熱処理を施すことで、充放電容量が高く、高速充放電特性に優れたリチウムイオン電池用負極を製造することができる。また、かかる方法で製造された負極を具え、充放電容量が高く、高速充放電特性に優れたリチウムイオン電池を提供することができる。   According to the present invention, a compound having an aromatic ring is electrooxidatively polymerized on a conductive substrate to form a fibril-like polymer, and the fibril-like polymer is baked to form carbon fibers. A lithium ion battery negative electrode with high charge / discharge capacity and high-speed charge / discharge characteristics by applying a heat treatment after coating the conductive metal with a metal capable of inserting and extracting lithium on the conductive metal Can be manufactured. In addition, it is possible to provide a lithium ion battery having a negative electrode manufactured by such a method, having a high charge / discharge capacity, and excellent in high-speed charge / discharge characteristics.

＜リチウムイオン電池用負極の製造方法＞
以下に、図１を参照しながら、本発明のリチウムイオン電池用負極の製造方法を詳細に説明する。本発明のリチウムイオン電池用負極の製造方法は、(i)導電性基板１上において、芳香環を有する化合物を電解酸化重合してフィブリル状ポリマーを生成させる工程と、(ii)該フィブリル状ポリマーを焼成して導電性基板１上に炭素繊維２を形成する工程と、(iii)該炭素繊維２を導電性金属３で被覆する工程と、(iv)該導電性金属３上にリチウムを吸蔵・脱離可能な金属４を担持する工程と、(v)真空中、200〜900℃で熱処理を行う工程とを含むことを特徴とし、該方法によれば、導電性基板１と、該導電性基板１上に形成された炭素繊維２と、該炭素繊維２を被覆する導電性金属３と、該導電性金属３上に担持されたリチウムを吸蔵・脱離可能な金属４とからなるリチウムイオン電池用負極を製造することができる。 <Method for producing negative electrode for lithium ion battery>
Below, the manufacturing method of the negative electrode for lithium ion batteries of this invention is demonstrated in detail, referring FIG. The method for producing a negative electrode for a lithium ion battery according to the present invention comprises: (i) a step of electrolytically polymerizing a compound having an aromatic ring on the conductive substrate 1 to form a fibril polymer; and (ii) the fibril polymer. Firing carbon to form carbon fibers 2 on the conductive substrate 1, (iii) coating the carbon fibers 2 with the conductive metal 3, and (iv) occlusion of lithium on the conductive metal 3. A step of supporting the detachable metal 4 and (v) a step of performing a heat treatment at 200 to 900 ° C. in a vacuum. According to the method, the conductive substrate 1 and the conductive material Lithium comprising carbon fiber 2 formed on conductive substrate 1, conductive metal 3 covering carbon fiber 2, and metal 4 capable of inserting and extracting lithium supported on conductive metal 3. An anode for an ion battery can be manufactured.

上記リチウムイオン電池用負極を構成する炭素繊維は、３次元網目構造を有し、該網目構造がリチウムを吸蔵・脱離可能な金属の電気化学反応に伴う体積変化を効率よく吸収するため、電気的に絶縁となる部分が生じ難く、充放電容量が低下し難く、また、高速充放電特性の向上にも好適である。また、該炭素繊維が導電性金属で被覆されることにより、負極における導電性が更に確保される上、熱処理によって、導電性金属とリチウムを吸蔵・脱離可能な金属との密着力が向上し、更に優れた高速充放電特性を達成することが可能となる。そのため、該リチウムイオン電池用負極を用いたリチウムイオン電池は、充放電容量が高い上、高速充放電特性に特に優れる。   The carbon fiber constituting the negative electrode for a lithium ion battery has a three-dimensional network structure, and the network structure efficiently absorbs a volume change associated with an electrochemical reaction of a metal capable of inserting and extracting lithium. Therefore, it is difficult to produce an insulating portion, the charge / discharge capacity is hardly lowered, and it is suitable for improving high-speed charge / discharge characteristics. In addition, by covering the carbon fiber with a conductive metal, the conductivity of the negative electrode is further secured, and the heat treatment improves the adhesion between the conductive metal and the metal capable of inserting and extracting lithium. Furthermore, it becomes possible to achieve further excellent high-speed charge / discharge characteristics. Therefore, a lithium ion battery using the negative electrode for a lithium ion battery has a high charge / discharge capacity and is particularly excellent in high-speed charge / discharge characteristics.

本発明のリチウムイオン電池用負極の製造方法では、(i)工程で、導電性基板１上において、芳香環を有する化合物を電解酸化重合してフィブリル状ポリマーを形成する。使用する導電性基板１としては、導電性を有する限り特に限定されず、ステンレス、チタン、ニッケル等のプレートが挙げられる。また、上記芳香環を有する化合物としては、ベンゼン環を有する化合物、芳香族複素環を有する化合物を挙げることができる。ここで、ベンゼン環を有する化合物としては、アニリン及びアニリン誘導体が好ましく、芳香族複素環を有する化合物としては、ピロール、チオフェン及びこれらの誘導体が好ましい。これら芳香環を有する化合物は、一種単独で用いてもよいし、二種以上の混合物として用いてもよい。   In the method for producing a negative electrode for a lithium ion battery of the present invention, in step (i), a compound having an aromatic ring is electrolytically oxidized and polymerized on the conductive substrate 1 to form a fibril polymer. The conductive substrate 1 to be used is not particularly limited as long as it has conductivity, and examples thereof include plates made of stainless steel, titanium, nickel, and the like. Examples of the compound having an aromatic ring include a compound having a benzene ring and a compound having an aromatic heterocycle. Here, as the compound having a benzene ring, aniline and aniline derivatives are preferable, and as the compound having an aromatic heterocyclic ring, pyrrole, thiophene and derivatives thereof are preferable. These compounds having an aromatic ring may be used singly or as a mixture of two or more.

上記電解酸化重合においては、原料の芳香環を有する化合物と共に、酸を混在させることが好ましい。この場合、酸の負イオンがドーパントとして合成されるフィブリル状ポリマー中に取り込まれ、導電性に優れたフィブリル状ポリマーが得られ、このフィブリル状ポリマーを用いることにより最終的に炭素繊維の導電性を更に向上させることができる。ここで、電解酸化重合の際に混在させる酸としては、Ｈ2ＳＯ4、ＨＢＦ4、ＨＣｌ、ＨＣｌＯ4等を例示することができる。また、該酸の濃度は、0.1〜3 mol/Lの範囲が好ましく、0.5〜2.5 mol/Lの範囲が更に好ましい。 In the electrolytic oxidation polymerization, it is preferable to mix an acid together with a raw material compound having an aromatic ring. In this case, the negative ion of the acid is taken into the fibril polymer synthesized as a dopant to obtain a fibril polymer excellent in conductivity. By using this fibril polymer, the conductivity of the carbon fiber is finally improved. Further improvement can be achieved. Here, examples of the acid mixed in the electrolytic oxidation polymerization include H 2 SO 4 , HBF 4 , HCl, and HClO 4 . The acid concentration is preferably in the range of 0.1 to 3 mol / L, more preferably in the range of 0.5 to 2.5 mol / L.

上記(i)工程は、芳香環を有する化合物を含む溶液中に、上記導電性基板を作用極として浸漬し、更に対極を浸漬し、両極間に芳香環を有する化合物の酸化電位以上の電圧を印加するか、または該芳香環を有する化合物が重合するのに充分な電圧が確保できるような条件の電流を通電すればよく、これにより導電性基板（作用極）上にフィブリル状ポリマーが生成する。ここで、対極としては、ステンレススチール、白金、カーボン等の導電性物質からなる板や多孔質支持体等を用いることができる。この電解酸化重合法によるフィブリル状ポリマーの合成方法の一例を挙げると、Ｈ2ＳＯ4等の酸及びアニリン等の芳香環を有する化合物を含む電解溶液中に導電性基板からなる作用極及び対極を浸漬し、両極間に0.1〜1000 mA/cm2、好ましくは0.2〜100 mA/cm2の電流を通電して、導電性基板からなる作用極側にフィブリル状ポリマーを重合析出させる方法等が例示される。なお、フィブリル状ポリマーは、導電性基板からなる作用極の対極と対向する面に主として生成する。ここで、芳香環を有する化合物の電解溶液中の濃度は、0.05〜3 mol/Lが好ましく、0.25〜1.5 mol/Lがより好ましい。また、電解溶液には、上記成分に加え、ｐＨを調製するために可溶性塩等を適宜添加してもよい。 In the step (i), the conductive substrate is immersed in a solution containing a compound having an aromatic ring as a working electrode, the counter electrode is further immersed, and a voltage equal to or higher than the oxidation potential of the compound having an aromatic ring between both electrodes is applied. The fibrillar polymer is generated on the conductive substrate (working electrode) by applying or applying a current under such a condition that a voltage sufficient to polymerize the compound having an aromatic ring can be secured. . Here, as the counter electrode, a plate made of a conductive material such as stainless steel, platinum, or carbon, a porous support, or the like can be used. An example of a method for synthesizing a fibrillated polymer by this electrolytic oxidation polymerization method is as follows. An working electrode and a counter electrode made of a conductive substrate are included in an electrolytic solution containing an acid such as H 2 SO 4 and a compound having an aromatic ring such as aniline. Exemplified is a method of polymerizing and depositing a fibrillated polymer on the working electrode side made of a conductive substrate by immersing and applying a current of 0.1 to 1000 mA / cm 2 , preferably 0.2 to 100 mA / cm 2 between both electrodes Is done. The fibril polymer is mainly generated on the surface facing the counter electrode of the working electrode made of a conductive substrate. Here, the concentration of the compound having an aromatic ring in the electrolytic solution is preferably 0.05 to 3 mol / L, and more preferably 0.25 to 1.5 mol / L. Moreover, in addition to the said component, you may add a soluble salt etc. to an electrolyte solution suitably in order to adjust pH.

上記芳香環を有する化合物を電解酸化重合して得られるフィブリル状ポリマーは、通常、３次元連続構造を有し、直径が30〜数百nmで、好ましくは40〜500 nmであり、長さが0.5μm〜100 mmで、好ましくは1μm〜10 mmである。   The fibrillar polymer obtained by electrolytic oxidation polymerization of the compound having an aromatic ring usually has a three-dimensional continuous structure, has a diameter of 30 to several hundred nm, preferably 40 to 500 nm, and has a length of It is 0.5 μm to 100 mm, preferably 1 μm to 10 mm.

本発明のリチウムイオン電池用負極の製造方法では、(ii)工程で、上記フィブリル状ポリマーを焼成し炭化することで、導電性基板１上に炭素繊維２を形成する。なお、(ii)工程の前に、フィブリル状ポリマーを水や有機溶剤等の溶媒で洗浄し、乾燥させることが好ましい。ここで、乾燥方法としては、特に制限されるものではないが、風乾、真空乾燥の他、流動床乾燥装置、気流乾燥機、スプレードライヤー等を使用した方法を例示することができる。   In the method for producing a negative electrode for a lithium ion battery of the present invention, the carbon fiber 2 is formed on the conductive substrate 1 by firing and carbonizing the fibrillated polymer in the step (ii). In addition, before the step (ii), it is preferable that the fibrillated polymer is washed with a solvent such as water or an organic solvent and dried. Here, the drying method is not particularly limited, and examples thereof include a method using a fluidized bed drying device, an air dryer, a spray dryer, etc., in addition to air drying and vacuum drying.

上記(ii)工程の焼成条件としては、特に限定されるものではなく、最適導電率となるように適宜設定すればよいが、特に高導電率を必要とする場合は、温度500〜3000℃、好ましくは600〜2800℃で、0.5〜6時間焼成することが好ましい。なお、本発明の製造方法では、焼成工程を非酸化性雰囲気中で行うことが好ましく、該非酸化性雰囲気としては、窒素雰囲気、アルゴン雰囲気、ヘリウム雰囲気等を挙げることができ、場合によっては水素雰囲気とすることもできる。   The firing conditions in the above step (ii) are not particularly limited, and may be set as appropriate so as to obtain optimum conductivity. Particularly, when high conductivity is required, the temperature is 500 to 3000 ° C., Preferably, baking is performed at 600 to 2800 ° C. for 0.5 to 6 hours. In the production method of the present invention, the firing step is preferably performed in a non-oxidizing atmosphere, and examples of the non-oxidizing atmosphere include a nitrogen atmosphere, an argon atmosphere, and a helium atmosphere. It can also be.

上記炭素繊維は、通常、３次元連続構造を有し、直径が30〜数百nm、好ましくは40〜500 nmであり、長さが0.5μm〜100 mm、好ましくは1μm〜10 mmであり、表面抵抗が106〜10-2Ω、好ましくは104〜10-2Ωである。また、該炭素繊維は、残炭率が90〜20％、好ましくは80〜25％である。該炭素繊維は、カーボン全体が３次元に連続した構造を有するため、粒状カーボンよりも導電性が高い。 The carbon fiber usually has a three-dimensional continuous structure, has a diameter of 30 to several hundred nm, preferably 40 to 500 nm, and a length of 0.5 μm to 100 mm, preferably 1 μm to 10 mm. The surface resistance is 10 6 to 10 −2 Ω, preferably 10 4 to 10 −2 Ω. The carbon fiber has a residual carbon ratio of 90 to 20%, preferably 80 to 25%. Since the carbon fiber has a structure in which the entire carbon is three-dimensionally continuous, the carbon fiber has higher conductivity than the granular carbon.

本発明のリチウムイオン電池用負極の製造方法では、(iii)工程で、上記導電性基板１上に形成された炭素繊維２を導電性金属３で被覆する。ここで、導電性金属としては、Ｃｕ、Ｎｉ、Ｚｎ等が挙げられ、これらの中でも、導電性の観点から、Ｃｕが特に好ましい。   In the method for producing a negative electrode for a lithium ion battery of the present invention, the carbon fiber 2 formed on the conductive substrate 1 is covered with the conductive metal 3 in the step (iii). Here, examples of the conductive metal include Cu, Ni, Zn, and the like. Among these, Cu is particularly preferable from the viewpoint of conductivity.

上記導電性金属による炭素繊維の被覆法としては、特に限定されるものではなく、例えば、無電解メッキ法、電解メッキ法等が挙げられる。また、導電性金属３の被覆量は、特に限定されるものではないが、0.05〜0.1 mg/cm2の範囲が好ましい。導電性金属３の被覆量が0.05 mg/cm2未満では、導電性被覆が1 nm以下と薄く不安定であり、一方、0.1 mg/cm2を超えると、導電性は確保できるが、その分、リチウムを吸蔵・脱離可能な金属の付着占有体積が減少してしまう。 The method for coating the carbon fiber with the conductive metal is not particularly limited, and examples thereof include an electroless plating method and an electrolytic plating method. Moreover, the coating amount of the conductive metal 3 is not particularly limited, but a range of 0.05 to 0.1 mg / cm 2 is preferable. When the coating amount of the conductive metal 3 is less than 0.05 mg / cm 2 , the conductive coating is thin and unstable at 1 nm or less. On the other hand, when it exceeds 0.1 mg / cm 2 , the conductivity can be secured. In addition, the volume occupied by the metal capable of inserting and extracting lithium decreases.

本発明のリチウムイオン電池用負極の製造方法では、(iv)工程で、上記導電性金属３上にリチウムを吸蔵・脱離可能な金属４を担持する。ここで、リチウムを吸蔵・脱離可能な金属としては、Ｓｎ（融点228℃）、Ｓｉ（融点1410℃）、Ｐｂ（融点327℃）、Ａｌ（融点660℃）、Ａｕ（融点1064℃）、Ｐｔ（融点2041℃）、Ｉｎ（融点156℃）、Ｚｎ（融点419℃）、Ｃｄ（融点261℃）、Ａｇ（融点961℃）及びＭｇ（融点650℃）等が挙げられ、これらの中でも、充放電容量と融点の観点から、Ｓｎが特に好ましい。   In the method for producing a negative electrode for a lithium ion battery of the present invention, the metal 4 capable of inserting and extracting lithium is supported on the conductive metal 3 in the step (iv). Here, as a metal capable of inserting and extracting lithium, Sn (melting point 228 ° C.), Si (melting point 1410 ° C.), Pb (melting point 327 ° C.), Al (melting point 660 ° C.), Au (melting point 1064 ° C.), Pt (melting point 2041 ° C.), In (melting point 156 ° C.), Zn (melting point 419 ° C.), Cd (melting point 261 ° C.), Ag (melting point 961 ° C.), Mg (melting point 650 ° C.), etc. Among these, From the viewpoint of charge / discharge capacity and melting point, Sn is particularly preferable.

上記リチウムを吸蔵・脱離可能な金属４の導電性金属３上への担持法としては、電解メッキ法、無電解メッキ法、スパッタリング法等が挙げられるが、担持率の調整が容易な点で、電解メッキ法が好ましい。該電解メッキ法では、メッキしたい金属のイオンを含む溶液を調製し、該溶液に上記炭素繊維を浸漬し、所定の電圧を印加することで、溶液からリチウムを吸蔵・脱離可能な金属４を導電性金属３上に電気化学的に析出させることができ、しかも通電電荷量で金属４の析出量を制御することができる。なお、リチウムを吸蔵・脱離可能な金属４の担持量は、1.7〜5 mg/cm2の範囲が好ましい。リチウムを吸蔵・脱離可能な金属４の担持量が1.7 mg/cm2未満では、充放電容量が不足し、一方、5 mg/cm2を超えると、被膜厚の増大により、空隙が閉塞され、反応不活性な金属が発生し、利用効率が低下する。 Examples of the method for supporting the metal 4 capable of inserting and extracting lithium on the conductive metal 3 include an electrolytic plating method, an electroless plating method, and a sputtering method. However, it is easy to adjust the supporting rate. Electrolytic plating is preferred. In the electrolytic plating method, a solution containing ions of a metal to be plated is prepared, the carbon fiber is immersed in the solution, and a predetermined voltage is applied to obtain a metal 4 capable of inserting and extracting lithium from the solution. It can be electrochemically deposited on the conductive metal 3, and the amount of metal 4 deposited can be controlled by the amount of electric charge. The supported amount of metal 4 capable of inserting and extracting lithium is preferably in the range of 1.7 to 5 mg / cm 2 . When the supported amount of metal 4 capable of occluding and desorbing lithium is less than 1.7 mg / cm 2 , the charge / discharge capacity is insufficient, while when it exceeds 5 mg / cm 2 , the gap is closed due to the increase in film thickness. , Reaction inactive metal is generated, and the utilization efficiency is lowered.

本発明のリチウムイオン電池用負極の製造方法では、上記(iv)工程の後、(v)工程で、真空中、200〜900℃で熱処理を行う。ここで、熱処理の温度が200℃未満では、熱処理によるＳｎ等のリチウムを吸蔵・脱離可能な金属の融解及び導電性金属との合金化が困難であり、一方、900℃を超えると、Ｃｕ等の導電性金属が融解してしまう。また、熱処理を真空中で行わないと、Ｓｎ等のリチウムを吸蔵・脱離可能な金属と酸素が反応して、酸化スズ等の金属酸化物が生成してしまう。   In the method for producing a negative electrode for a lithium ion battery of the present invention, heat treatment is performed at 200 to 900 ° C. in vacuum in the step (v) after the step (iv). Here, if the temperature of the heat treatment is less than 200 ° C., it is difficult to melt the metal capable of occluding and desorbing lithium such as Sn and alloying with the conductive metal by heat treatment. Such a conductive metal melts. In addition, if the heat treatment is not performed in a vacuum, a metal capable of inserting and extracting lithium such as Sn reacts with oxygen to generate a metal oxide such as tin oxide.

上記熱処理工程(v)は、3 hPa以下の真空下で行うことが好ましい。また、上記熱処理工程(v)は、上記の温度範囲で8〜24時間行うことが好ましい。上記温度範囲での熱処理を8時間以上行うことで、導電性金属３とリチウムを吸蔵・脱離可能な金属４との密着力を十分に向上させることができる。   The heat treatment step (v) is preferably performed under a vacuum of 3 hPa or less. The heat treatment step (v) is preferably performed in the above temperature range for 8 to 24 hours. By performing the heat treatment in the above temperature range for 8 hours or more, the adhesion between the conductive metal 3 and the metal 4 capable of inserting and extracting lithium can be sufficiently improved.

上記のようにして製造したリチウムイオン電池用負極の形状としては、特に制限はなく、電極として公知の形状の中から適宜選択することができる。例えば、シート状、円柱形状、板状形状、スパイラル形状等が挙げられる。   There is no restriction | limiting in particular as a shape of the negative electrode for lithium ion batteries manufactured as mentioned above, It can select suitably from well-known shapes as an electrode. For example, a sheet shape, a columnar shape, a plate shape, a spiral shape, and the like can be given.

＜リチウムイオン電池＞
次に、本発明のリチウムイオン電池を詳細に説明する。本発明のリチウムイオン電池は、上述した方法で製造されたリチウムイオン電池用負極を備え、更に、正極、電解質、セパレーター等のリチウムイオン電池の技術分野で通常使用されている他の部材を備える。本発明のリチウムイオン電池は、上述した方法で製造されたリチウムイオン電池用負極を備えるため、充放電容量が高く、高速充放電特性に特に優れる。 <Lithium ion battery>
Next, the lithium ion battery of the present invention will be described in detail. The lithium ion battery of the present invention includes a negative electrode for a lithium ion battery manufactured by the above-described method, and further includes other members that are usually used in the technical field of lithium ion batteries, such as a positive electrode, an electrolyte, and a separator. Since the lithium ion battery of this invention is equipped with the negative electrode for lithium ion batteries manufactured by the method mentioned above, its charge / discharge capacity is high and it is especially excellent in a high-speed charge / discharge characteristic.

本発明のリチウムイオン電池の正極の活物質としては、ＬｉＣｏＯ2、ＬｉＮｉＯ2、ＬｉＭｎ2Ｏ4、ＬｉＦｅＯ2及びＬｉＦｅＰＯ4等のリチウム含有複合酸化物、リチウム金属、Ｖ2Ｏ5、Ｖ6Ｏ13、ＭｎＯ2、ＭｎＯ3等の金属酸化物、ＴｉＳ2、ＭｏＳ2等の金属硫化物、ポリアニリン等の導電性ポリマー等が好適に挙げられる。これら正極活物質は、１種単独で使用してもよく、２種以上を併用してもよい。上記正極には、必要に応じて導電助剤、結着剤を混合することができ、導電助剤としてはアセチレンブラック等が挙げられ、結着剤としてはポリフッ化ビニリデン（ＰＶＤＦ）、ポリテトラフルオロエチレン（ＰＴＦＥ）、スチレン・ブタジエンゴム（ＳＢＲ）、カルボキシメチルセルロース（ＣＭＣ）等が挙げられる。これらの添加剤は、従来と同様の配合割合で用いることができる。 As an active material of the positive electrode of the lithium ion battery of the present invention, lithium-containing composite oxides such as LiCoO 2 , LiNiO 2 , LiMn 2 O 4 , LiFeO 2 and LiFePO 4 , lithium metal, V 2 O 5 , V 6 O 13 Preferable examples include metal oxides such as MnO 2 and MnO 3 , metal sulfides such as TiS 2 and MoS 2 , and conductive polymers such as polyaniline. These positive electrode active materials may be used individually by 1 type, and may use 2 or more types together. If necessary, the positive electrode can be mixed with a conductive additive and a binder. Examples of the conductive assistant include acetylene black, and the binder includes polyvinylidene fluoride (PVDF), polytetrafluoro. Examples include ethylene (PTFE), styrene / butadiene rubber (SBR), carboxymethyl cellulose (CMC), and the like. These additives can be used at a blending ratio similar to the conventional one.

本発明のリチウムイオン電池の電解質としては、非水電解液やポリマー電解質を使用することができる。該非水電解液は、通常、非プロトン性有機溶媒に支持塩を溶解させてなり、所望に応じて各種添加剤を含有してもよい。ここで、該非プロトン性溶媒としては、１,２-ジメトキシエタン、テトラヒドロフラン、ジメチルカーボネート、ジエチルカーボネート、ジフェニルカーボネート、エチレンカーボネート、プロピレンカーボネート、γ-ブチロラクトン、γ-バレロラクトン、エチルメチルカーボネート等が挙げられる。また、支持塩としては、ＬｉＰＦ6、ＬｉＣｌＯ4、ＬｉＢＦ4、ＬｉＢＣ4Ｏ8、ＬｉＣＦ3ＳＯ3、ＬｉＡｓＦ6、ＬｉＣ4Ｆ9ＳＯ3、Ｌｉ(ＣＦ3ＳＯ2)2Ｎ及びＬｉ(Ｃ2Ｆ5ＳＯ2)2Ｎ等のリチウム塩が挙げられる。なお非水電解液中の支持塩の濃度としては、特に限定されるものではないが、0.2〜1.5 mol/L（Ｍ）の範囲が好ましい。 As the electrolyte of the lithium ion battery of the present invention, a nonaqueous electrolytic solution or a polymer electrolyte can be used. The nonaqueous electrolytic solution is usually prepared by dissolving a supporting salt in an aprotic organic solvent, and may contain various additives as desired. Here, examples of the aprotic solvent include 1,2-dimethoxyethane, tetrahydrofuran, dimethyl carbonate, diethyl carbonate, diphenyl carbonate, ethylene carbonate, propylene carbonate, γ-butyrolactone, γ-valerolactone, and ethyl methyl carbonate. . Further, as supporting salts, LiPF 6 , LiClO 4 , LiBF 4 , LiBC 4 O 8 , LiCF 3 SO 3 , LiAsF 6 , LiC 4 F 9 SO 3 , Li (CF 3 SO 2 ) 2 N and Li (C 2 Examples thereof include lithium salts such as F 5 SO 2 ) 2 N. The concentration of the supporting salt in the nonaqueous electrolytic solution is not particularly limited, but is preferably in the range of 0.2 to 1.5 mol / L (M).

また、上記ポリマー電解質は、ポリマーと上記支持塩とを含むことが好ましく、更に上記非プロトン性有機溶媒を含むことが更に好ましく、目的に応じて種々の添加剤を更に含有してもよい。上記ポリマー電解質に用いるポリマーとしては、ポリマー電池用のゲル電解質に通常用いられるポリマーの総てを用いることができ、具体的には、ポリエチレンオキシド、ポリプロピレンオキシド、ポリアクリレート、ポリアクリロニトリル、エチレンオキシドユニットを含むポリアクリレート等が挙げられる。   The polymer electrolyte preferably contains a polymer and the supporting salt, more preferably contains the aprotic organic solvent, and may further contain various additives depending on the purpose. As the polymer used for the polymer electrolyte, all polymers usually used for gel electrolytes for polymer batteries can be used, and specifically include polyethylene oxide, polypropylene oxide, polyacrylate, polyacrylonitrile, ethylene oxide units. Polyacrylate etc. are mentioned.

本発明のリチウムイオン電池に使用できる他の部材としては、正負極間に、両極の接触による電流の短絡を防止する役割で介在させるセパレーターが挙げられる。セパレーターの材質としては、両極の接触を確実に防止し得、且つ電解液を通したり含んだりできる材料、例えば、ポリテトラフルオロエチレン、ポリプロピレン、ポリエチレン、セルロース系、ポリブチレンテレフタレート、ポリエチレンテレフタレート等の合成樹脂製の不織布、薄層フィルム等が好適に挙げられる。これらは、単体でも、混合物でも、共重合体でもよい。これらの中でも、厚さ20〜50μm程度のポリプロピレン又はポリエチレン製の微孔性フィルム、セルロース系、ポリブチレンテレフタレート、ポリエチレンテレフタレート等のフィルムが特に好適である。本発明では、上述のセパレーターの他にも、通常電池に使用されている公知の各部材が好適に使用できる。   Other members that can be used in the lithium ion battery of the present invention include a separator interposed between positive and negative electrodes in a role of preventing current short-circuiting due to contact between both electrodes. As the material of the separator, it is possible to reliably prevent contact between the two electrodes and to allow the electrolyte to pass through or to contain, for example, synthesis of polytetrafluoroethylene, polypropylene, polyethylene, cellulose, polybutylene terephthalate, polyethylene terephthalate, etc. Preferred examples include resin non-woven fabrics and thin layer films. These may be a single substance, a mixture or a copolymer. Of these, polypropylene or polyethylene microporous films having a thickness of about 20 to 50 μm, cellulose-based films, polybutylene terephthalate, polyethylene terephthalate, and the like are particularly suitable. In the present invention, in addition to the separators described above, known members that are normally used in batteries can be suitably used.

以上に説明した本発明のリチウムイオン電池の形態としては、特に制限はなく、コインタイプ、ボタンタイプ、ペーパータイプ、角型又はスパイラル構造の円筒型電池等、種々の公知の形態が好適に挙げられる。ボタンタイプの場合は、シート状の正極及び負極を作製し、該正極及び負極でセパレーターを挟む等して、リチウムイオン電池を作製することができる。また、スパイラル構造の場合は、例えば、シート状の正極を作製して集電体を挟み、これにシート状の負極を重ね合わせて巻き上げる等して、リチウムイオン電池を作製することができる。   The form of the lithium ion battery of the present invention described above is not particularly limited, and various known forms such as a coin type, a button type, a paper type, a square type or a spiral type cylindrical battery are preferably exemplified. . In the case of the button type, a lithium ion battery can be manufactured by preparing a sheet-like positive electrode and negative electrode and sandwiching a separator between the positive electrode and the negative electrode. In the case of a spiral structure, for example, a lithium ion battery can be manufactured by preparing a sheet-like positive electrode, sandwiching a current collector, and stacking and winding up the sheet-like negative electrode on the current collector.

以下に、実施例を挙げて本発明を更に詳しく説明するが、本発明は下記の実施例に何ら限定されるものではない。   Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples.

（実施例１）
＜金属担持炭素繊維−基板複合体の製造＞
アニリンモノマー 0.5 mol/LとＨ2ＳＯ4 1.0 mol/Lとを含む酸性水溶液中に、作用極としてＳＵＳ３１６製の導電性基板を設置し、対極として白金板を設置し、室温にて20 mA/cm2の定電流で1時間電解酸化重合を行い、作用極上にポリアニリンを電析させた。得られたポリアニリン膜をイオン交換水で十分に洗浄した後、100℃で乾燥し、基板−ポリアニリン複合体を得た。ＳＥＭで観察したところ、直径が100〜300 nmのフィブリル状ポリアニリンが絡み合ったような状態で得られていることが確認された。 Example 1
<Production of metal-supported carbon fiber-substrate composite>
In an acidic aqueous solution containing aniline monomer 0.5 mol / L and H 2 SO 4 1.0 mol / L, a conductive substrate made of SUS316 was installed as the working electrode, a platinum plate was installed as the counter electrode, and 20 mA / Electrolytic oxidation polymerization was performed at a constant current of cm 2 for 1 hour, and polyaniline was electrodeposited on the working electrode. The obtained polyaniline film was sufficiently washed with ion exchange water and then dried at 100 ° C. to obtain a substrate-polyaniline complex. When observed by SEM, it was confirmed that fibrillar polyaniline having a diameter of 100 to 300 nm was obtained in an intertwined state.

得られた基板−ポリアニリン複合体をＡｒ雰囲気中7℃/分の昇温速度で900℃まで加熱し、更に900℃で1時間保持して焼成処理を行った。得られた焼成物をＳＥＭで観察したところ、直径が50〜200 nmで、焼成処理前とほぼ同様な形状の炭素繊維が得られていることが確認された。   The obtained substrate-polyaniline complex was heated to 900 ° C. at a rate of temperature increase of 7 ° C./min in an Ar atmosphere, and further held at 900 ° C. for 1 hour to perform a firing treatment. When the obtained fired product was observed with an SEM, it was confirmed that carbon fibers having a diameter of 50 to 200 nm and substantially the same shape as before firing were obtained.

上記で得られた基板−炭素繊維複合体を一般的な触媒化プロセス後、硫酸銅メッキ浴にて無電解銅メッキを行い、0.05〜0.1 mg/cm2の付着量で、炭素繊維を銅で被覆した。 After the substrate-carbon fiber composite obtained above is subjected to a general catalytic process, electroless copper plating is performed in a copper sulfate plating bath, and the carbon fiber is made of copper with an adhesion amount of 0.05 to 0.1 mg / cm 2. Covered.

次に、アルカンスルホン酸第一スズ溶液（Ｓｎ2+：18 g/L）に浸漬し、10 mA/cm2の定電流で電解メッキを行い、スズを微粒子として2.4 mg/cm2担持させ、銅を下地メッキとしたスズ担持炭素繊維−基板複合体を得た。 Next, it is immersed in stannous alkane sulfonate solution (Sn 2+ : 18 g / L), electroplated at a constant current of 10 mA / cm 2 , and tin is supported as 2.4 mg / cm 2 as fine particles. A tin-supported carbon fiber-substrate composite with copper as the base plating was obtained.

更に、上記で得られたスズ担持炭素繊維−基板複合体を、真空中（1.5 hPa）、200℃で24時間熱処理を行った。熱処理後のスズ担持炭素繊維−基板複合体をＳＥＭで観察したところ、図２（×50k）に示すように、微粒子化した結晶粒でＳｎメッキされたフィブリル状の構造体が得られていることが確認できた。   Further, the tin-supported carbon fiber-substrate composite obtained above was heat-treated at 200 ° C. for 24 hours in a vacuum (1.5 hPa). When the tin-supported carbon fiber-substrate composite after heat treatment was observed with an SEM, a fibril-like structure plated with Sn with finely divided crystal grains was obtained as shown in FIG. 2 (× 50k). Was confirmed.

＜リチウムイオン電池用負極の評価＞
次に、上記のようにして得られたスズ担持炭素繊維−基板複合体を16 mmφのサイズに打ち抜き、負極を作製した。この負極を用いて、リチウムメタルを正極とするハーフセルを組み立て、高速充放電試験を行った。なお、電解液としては、エチレンカーボネート（ＥＣ）及びエチルメチルカーボネート（ＥＭＣ）の混合溶媒（ＥＣ／ＥＭＣ体積比＝１／２）に、ＬｉＰＦ6（支持塩）を1.0Ｍ（mol/L）の濃度で溶解させた非水電解液を使用した。また、高速充放電試験において、充電は、0.5 mA、5 mA、10 mAの各定電流で充電後、定電圧で5分間保持して行い、放電は、0.5 mA、5 mA、10 mAの各定電流で放電し、下限電圧を1.5Ｖとした。0.5 mAで充放電を繰り返し、10サイクル後の放電容量を電極の体積で除した値を0.5 mA充放電時の比容量とした。また、10 mAで充放電を4サイクル繰り返し、その平均放電容量を電極の体積で除した値を10 mA高速充放電時の比容量とした。 <Evaluation of negative electrode for lithium ion battery>
Next, the tin-supported carbon fiber-substrate composite obtained as described above was punched out to a size of 16 mmφ to produce a negative electrode. Using this negative electrode, a half cell having lithium metal as the positive electrode was assembled, and a high-speed charge / discharge test was conducted. As an electrolytic solution, a mixed solvent of ethylene carbonate (EC) and ethyl methyl carbonate (EMC) (EC / EMC volume ratio = 1/2) and LiPF 6 (supporting salt) of 1.0 M (mol / L) are used. A non-aqueous electrolyte dissolved in a concentration was used. In the fast charge / discharge test, charging is performed at a constant current of 0.5 mA, 5 mA, and 10 mA and then held at a constant voltage for 5 minutes, and discharging is performed at 0.5 mA, 5 mA, and 10 mA. The battery was discharged at a constant current, and the lower limit voltage was 1.5V. Charge / discharge was repeated at 0.5 mA, and the value obtained by dividing the discharge capacity after 10 cycles by the volume of the electrode was taken as the specific capacity at 0.5 mA charge / discharge. Further, charging / discharging was repeated 4 cycles at 10 mA, and the value obtained by dividing the average discharge capacity by the volume of the electrode was taken as the specific capacity during 10 mA high-speed charging / discharging.

（比較例１）
銅を下地メッキとしたスズ担持炭素繊維−基板複合体を熱処理しない以外は、実施例１と同様にして、スズ担持炭素繊維−基板複合体を得た。得られたスズ担持炭素繊維−基板複合体のＳＥＭ写真（×50k）を図３に示す。また、得られたスズ担持炭素繊維−基板複合体を用いて、実施例１と同様にしてハーフセルを組み立て、高速充放電試験を行った。 (Comparative Example 1)
A tin-supported carbon fiber-substrate composite was obtained in the same manner as in Example 1 except that the tin-supported carbon fiber-substrate composite with copper as the base plating was not heat-treated. The SEM photograph (x50k) of the obtained tin carrying | support carbon fiber-substrate composite is shown in FIG. Further, using the obtained tin-supported carbon fiber-substrate composite, a half cell was assembled in the same manner as in Example 1, and a high-speed charge / discharge test was performed.

以上の結果を図４に示す。図４から、比較例１のハーフセルに比べて、実施例１のハーフセルは、高容量で且つ優れた高速充放電特性を有することが確認できる。   The above results are shown in FIG. From FIG. 4, it can be confirmed that the half cell of Example 1 has a high capacity and excellent high-speed charge / discharge characteristics as compared with the half cell of Comparative Example 1.

本発明のリチウムイオン電池用負極の製造方法の工程図の一部である。It is a part of process drawing of the manufacturing method of the negative electrode for lithium ion batteries of this invention. 実施例１で得られた、銅を下地メッキとしたスズ担持炭素繊維−基板複合体の熱処理後のＳＥＭ写真である。It is a SEM photograph after heat processing of the tin carrying | support carbon fiber-substrate composite_body | complex obtained by Example 1 which used copper as the base plating. 比較例１で得られた、銅を下地メッキとしたスズ担持炭素繊維−基板複合体のＳＥＭ写真である。2 is an SEM photograph of a tin-supported carbon fiber-substrate composite obtained in Comparative Example 1 with copper as a base plating. 実施例１及び比較例１のハーフセルに対する高速充放電試験の結果を示す散布図である。It is a scatter diagram which shows the result of the high-speed charging / discharging test with respect to the half cell of Example 1 and Comparative Example 1.

符号の説明Explanation of symbols

１ 導電性基板
２ 炭素繊維
３ 導電性金属
４ リチウムを吸蔵・脱離可能な金属 DESCRIPTION OF SYMBOLS 1 Conductive substrate 2 Carbon fiber 3 Conductive metal 4 Metal which can occlude / release lithium

Claims (5)

導電性基板と、該導電性基板上に形成された炭素繊維と、該炭素繊維を被覆する導電性金属と、該導電性金属上に担持されたリチウムを吸蔵・脱離可能な金属とからなるリチウムイオン電池用負極の製造方法であって、
(i)導電性基板上において、芳香環を有する化合物を電解酸化重合してフィブリル状ポリマーを生成させる工程と、
(ii)該フィブリル状ポリマーを焼成して導電性基板上に炭素繊維を生成させる工程と、
(iii)該炭素繊維を導電性金属で被覆する工程と、
(iv)該導電性金属上にリチウムを吸蔵・脱離可能な金属を担持する工程と、
(v)真空中、200〜900℃で熱処理を行う工程と
を含むことを特徴とするリチウムイオン電池用負極の製造方法。 A conductive substrate, a carbon fiber formed on the conductive substrate, a conductive metal covering the carbon fiber, and a metal capable of inserting and extracting lithium supported on the conductive metal. A method for producing a negative electrode for a lithium ion battery, comprising:
(i) a step of electrolytically oxidatively polymerizing a compound having an aromatic ring on a conductive substrate to produce a fibrillated polymer;
(ii) firing the fibrillated polymer to form carbon fibers on a conductive substrate;
(iii) coating the carbon fiber with a conductive metal;
(iv) carrying a metal capable of inserting and extracting lithium on the conductive metal;
(v) A step of performing heat treatment at 200 to 900 ° C. in a vacuum, and a method for producing a negative electrode for a lithium ion battery. 前記熱処理工程(v)を3 hPa以下の真空下で8〜24時間行うことを特徴とする請求項１に記載のリチウムイオン電池用負極の製造方法。   The method for producing a negative electrode for a lithium ion battery according to claim 1, wherein the heat treatment step (v) is performed under a vacuum of 3 hPa or less for 8 to 24 hours. 前記炭素繊維を被覆する導電性金属がＣｕであることを特徴とする請求項１に記載のリチウムイオン電池用負極の製造方法。   2. The method for producing a negative electrode for a lithium ion battery according to claim 1, wherein the conductive metal covering the carbon fiber is Cu. 前記リチウムを吸蔵・脱離可能な金属がＳｎであることを特徴とする請求項１に記載のリチウムイオン電池用負極の製造方法。   2. The method for producing a negative electrode for a lithium ion battery according to claim 1, wherein the metal capable of inserting and extracting lithium is Sn. 請求項１〜４のいずれかに記載の方法で製造したリチウムイオン電池用負極を具えたリチウムイオン電池。   The lithium ion battery provided with the negative electrode for lithium ion batteries manufactured by the method in any one of Claims 1-4.
JP2008020313A 2008-01-31 2008-01-31 Method of manufacturing negative electrode for lithium-ion battery, and lithium-ion battery Withdrawn JP2009181827A (en)

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Cited By (2)

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JP2014531733A (en) * 2011-10-05 2014-11-27 ワンディー マテリアル エルエルシー Silicon nanostructured active material for lithium ion battery and related process, composition, component and device
US9812699B2 (en) 2011-10-05 2017-11-07 Oned Material Llc Silicon nanostructure active materials for lithium ion batteries and processes, compositions, components and devices related thereto
US10355266B2 (en) 2011-10-05 2019-07-16 Oned Material Llc Silicon nanostructure active materials for lithium ion batteries and processes, compositions, components and devices related thereto
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JP2021002532A (en) * 2011-10-05 2021-01-07 ワンディー マテリアル、 インコーポレイテッドＯｎｅＤ Ｍａｔｅｒｉａｌ， Ｉｎｃ． Silicon nanostructure active material for lithium ion battery and process, composition, component and device related thereto
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