JPH07105938A - Manufacture of negetive electrode for non-aqueous electrolyte secondary battery - Google Patents
Manufacture of negetive electrode for non-aqueous electrolyte secondary batteryInfo
- Publication number
- JPH07105938A JPH07105938A JP5253425A JP25342593A JPH07105938A JP H07105938 A JPH07105938 A JP H07105938A JP 5253425 A JP5253425 A JP 5253425A JP 25342593 A JP25342593 A JP 25342593A JP H07105938 A JPH07105938 A JP H07105938A
- Authority
- JP
- Japan
- Prior art keywords
- electrode
- negative electrode
- carbon
- discharge
- battery
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
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Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、非水電解質二次電池用
負極の製造法に関する。TECHNICAL FIELD The present invention relates to a method for producing a negative electrode for a non-aqueous electrolyte secondary battery.
【０００２】[0002]
【従来の技術】リチウムを負極とする非水電解質二次電
池は、起電力が高く、従来のニッケル−カドミウム蓄電
池や鉛蓄電池に較べ高エネルギー密度になると期待さ
れ、多くの研究がなされている。しかし、金属状のリチ
ウムを負極に用いると、充電時にデンドライトが発生
し、短絡を起こしやすく信頼性の低い電池となる。この
問題を解決するために、ＬｉとＡｌやＰｂとの合金負極
を用いることが検討された。これら合金負極を用いる
と、充電によりＬｉは負極合金中に吸蔵され、デンドラ
イトの発生がなく信頼性の高い電池となる。しかし、合
金負極の放電電位は金属Ｌｉに比べ約０．５Ｖ貴である
ため、電池の電圧も０．５Ｖ低下し、これにより電池の
エネルギー密度も低下する。2. Description of the Related Art Non-aqueous electrolyte secondary batteries using lithium as a negative electrode have high electromotive force and are expected to have higher energy density than conventional nickel-cadmium storage batteries and lead storage batteries, and many studies have been conducted. However, when metallic lithium is used for the negative electrode, a dendrite is generated during charging, a short circuit is likely to occur, and the battery has low reliability. In order to solve this problem, the use of an alloy negative electrode of Li and Al or Pb was studied. When these alloy negative electrodes are used, Li is occluded in the negative electrode alloy by charging, and dendrite is not generated, so that the battery has high reliability. However, since the discharge potential of the alloy negative electrode is about 0.5 V more noble than that of metallic Li, the voltage of the battery also drops by 0.5 V, which also reduces the energy density of the battery.
【０００３】一方、黒鉛などの炭素材料とＬｉの層間化
合物を負極活物質とする研究も活発になされている。こ
の化合物を用いる負極においても、充電時にはＬｉは炭
素の層間に入りデンドライトは発生しない。放電電位は
金属Ｌｉに較べ約０．１Ｖ貴であるため、電池電圧の低
下も小さい。これにより、より好ましい負極と言える。
通常、炭素質材料は、有機物を不活性雰囲気中でおよそ
４００〜３０００℃の加熱により分解し、炭素化、さら
には黒鉛化を行うことにより得られる。炭素質材料の出
発原料はほとんどの場合に有機物であり、炭素化工程で
ある１５００℃付近までの加熱により、ほとんど炭素原
子のみが残り、３０００℃近い高温までの加熱により黒
鉛構造を発達させる。この有機物原料としては、液相で
はピッチ、コ−ルタ−ル、あるいはコ−クスとピッチの
混合物などが用いられ、固相では木質原料、フラン樹
脂、セルロ−ス、ポリアクリロニトリル、レ−ヨンを挙
げることができる。また、気相では、メタン、プロパン
などの炭化水素ガスが用いられている。[0003] On the other hand, researches using an intercalation compound of a carbon material such as graphite and Li as a negative electrode active material have been actively conducted. Also in the negative electrode using this compound, Li enters the carbon layer during charging and no dendrite is generated. Since the discharge potential is about 0.1 V more noble than that of metallic Li, the decrease in battery voltage is small. This can be said to be a more preferable negative electrode.
Usually, the carbonaceous material is obtained by decomposing an organic substance by heating at about 400 to 3000 ° C. in an inert atmosphere, carbonizing, and further graphitizing. The starting material of the carbonaceous material is almost always an organic substance, and by heating up to around 1500 ° C., which is a carbonization step, almost only carbon atoms remain and heating up to a high temperature near 3000 ° C. develops a graphite structure. As the organic material, pitch, cortall, or a mixture of coke and pitch is used in the liquid phase, and in the solid phase, wood material, furan resin, cellulose, polyacrylonitrile, rayon are used. Can be mentioned. In the gas phase, hydrocarbon gas such as methane and propane is used.
【０００４】これまでに石油ピッチなどを出発原料と
し、一般的には２０００℃以上の高温で焼成し、発達し
たグラファイト構造を有する、いわゆる易黒鉛化炭素材
料や、フラン樹脂を始めとする熱硬化性樹脂を出発原料
として、２０００℃以下の比較的低温で焼成し、乱層構
造を有する、いわゆる難黒鉛化炭素材料を、リチウムを
吸蔵、放出させる非水電解質二次電池用負極材料として
用いる試みがなされている。また、天然黒鉛を負極活物
質として利用する検討も数多く行われている。天然黒鉛
は、一般的に結晶構造が完全なグラファイト構造を有
し、（００２）面の層間距離はｄ002＝３．３５オング
ストローム、結晶子サイズはＬｃ＞１０００オングスト
ロームを示す。このような、天然黒鉛にリチウムを吸
蔵、放出させる場合、他の炭素材料に比べて、より多く
の電気容量を可逆的に充放電することができる。現在で
は、理論上、最高の吸蔵状態であるＣ6Ｌｉ、すなわ
ち、電気容量は３７２Ａｈ／ｋｇに非常に近い値、例え
ば、３５０Ａｈ／ｋｇに達することが知られている。Up to now, a so-called easily graphitizable carbon material having a developed graphite structure, which has been generally burned at a high temperature of 2000 ° C. or higher, using petroleum pitch as a starting material, or a thermosetting material such as furan resin Of using a so-called non-graphitizable carbon material, which has a turbostratic structure and is burned at a relatively low temperature of 2000 ° C. or less, using a hydrophobic resin as a starting material, as a negative electrode material for a non-aqueous electrolyte secondary battery that occludes and releases lithium Has been done. In addition, many studies have been conducted on the use of natural graphite as a negative electrode active material. Natural graphite generally has a graphite structure having a perfect crystal structure, and the interlayer distance of (002) plane is d 002 = 3.35 angstrom, and the crystallite size is Lc> 1000 angstrom. When such natural graphite stores and releases lithium, it is possible to reversibly charge and discharge a larger electric capacity as compared with other carbon materials. At present, it is known that C 6 Li which is the highest occlusion state theoretically, that is, the electric capacity reaches a value very close to 372 Ah / kg, for example, 350 Ah / kg.
【０００５】[0005]
【発明が解決しようとする課題】しかし、このような結
晶性の高い炭素材料、たとえば天然黒鉛や人造黒鉛を負
極活物質とした場合にも大きい問題があった。一般に、
炭素材料はその結晶性を高める方法として、高い温度に
おいて黒鉛化を進めることが行われる。高温で黒鉛化を
行うほど炭素表面の親水性は低下し、いわゆる表面の濡
れ性が低下する。このために、負極として結晶性の高い
炭素材料を用いる場合、電解液と炭素材料の濡れ性が不
充分な状態となり、電解液に充分に接触しない炭素粒子
が多く存在することとなる。その結果、電池内部で所定
の電極面積を確保できなくなり、たとえば、定電流充放
電を行う場合には、実質的に電流密度が高いものとな
る。また、通常、炭素材料を用いた負極板の製造工程と
しては、活物質である炭素粉末に水と増粘剤を加え、さ
らに結着剤を加えたペ−スト状の電極合剤を作製し、こ
れを金属たとえばニッケルの箔上に印刷した後、乾燥を
行う。したがって、疎水性の高い炭素粉末を用いる場合
には、加える水の中で充分に分散することが難しい。こ
の対策としては、界面活性剤の添加が行われることが多
い。しかし、加えた界面活性剤は、電池内部で、保存中
に電解液の分解やリチウムイオンとの副反応などを起こ
しやすく、望ましくない。However, there is a big problem when such a carbon material having high crystallinity, such as natural graphite or artificial graphite, is used as the negative electrode active material. In general,
As a method of increasing the crystallinity of a carbon material, graphitization is carried out at a high temperature. The higher the graphitization temperature is, the lower the hydrophilicity of the carbon surface is, and the lower the so-called surface wettability. For this reason, when a carbon material having high crystallinity is used as the negative electrode, the wettability between the electrolytic solution and the carbon material is insufficient, and many carbon particles that do not come into sufficient contact with the electrolytic solution are present. As a result, a predetermined electrode area cannot be ensured inside the battery, and for example, when constant current charging / discharging is performed, the current density becomes substantially high. In addition, usually, as a manufacturing process of a negative electrode plate using a carbon material, a paste-like electrode mixture is prepared by adding water and a thickener to carbon powder as an active material, and further adding a binder. After printing this on a foil of metal such as nickel, it is dried. Therefore, when using carbon powder having high hydrophobicity, it is difficult to sufficiently disperse it in the added water. As a countermeasure against this, a surfactant is often added. However, the added surfactant is not desirable because it tends to cause decomposition of the electrolytic solution and side reactions with lithium ions during storage inside the battery.
【０００６】このような理由から、疎水性の高い炭素粉
末を用いる場合、合剤ペ−スト中の炭素材料の分散が不
充分な状態となり、一部の炭素粉末はそれら同志が凝集
したままで負極板が製造されることとなる。したがっ
て、充放電時には分極の増加が起こり、この問題は特に
充電時に深刻なものとなり、最悪の場合には炭素負極表
面に金属リチウムの析出が生ずる。この金属リチウムの
析出は充放電効率を低下させ、デンドライト発生による
正極との内部短絡を引き起こす。その結果、充放電サイ
クル特性は劣ったものとなる。本発明は、上記のような
課題を解決し、炭素材料のもつ特徴を生かして、電気容
量が大きく、充放電サイクル特性が良好な非水電解質二
次電池用負極を提供するものである。For this reason, when carbon powder having a high hydrophobicity is used, the carbon material in the mixture paste is insufficiently dispersed, and some carbon powders remain aggregated with each other. A negative electrode plate will be manufactured. Therefore, polarization is increased during charge and discharge, and this problem becomes serious especially during charge, and in the worst case, deposition of metallic lithium occurs on the carbon negative electrode surface. The deposition of metallic lithium lowers the charge / discharge efficiency and causes an internal short circuit with the positive electrode due to dendrite generation. As a result, the charge / discharge cycle characteristics are inferior. The present invention solves the above problems and provides a negative electrode for a non-aqueous electrolyte secondary battery, which has a large electric capacity and good charge / discharge cycle characteristics by utilizing the characteristics of a carbon material.
【０００７】[0007]
【課題を解決するための手段】本発明は、炭素材料を用
いる電極を製造するに際して、材料の段階でまたは電極
形成後にプラズマ処理を施すことを特徴とする。すなわ
ち、本発明は、少なくとも炭素材料と結着剤を含む電極
合剤をそのままもしくは集電体と一体に成形するか、ペ
ースト状にして集電体に塗布または充填することにより
炭素電極を製造する方法において、前記炭素粉末材料ま
たは電極形成後の電極表面にプラズマ処理をするもので
ある。The present invention is characterized in that, when manufacturing an electrode using a carbon material, a plasma treatment is performed at the material stage or after the electrode is formed. That is, according to the present invention, a carbon electrode is manufactured by forming an electrode mixture containing at least a carbon material and a binder as it is or integrally with a current collector, or by forming a paste and coating or filling the current collector. In the method, the carbon powder material or the electrode surface after the electrode is formed is subjected to plasma treatment.
【０００８】ここで、前記炭素材料は、Ｘ線広角回折法
による（００２）面の面間隔（ｄ002）が３．３５５〜
３．４０オングストロームであり、ｃ軸方向の結晶子の
大きさ（Ｌｃ）が２００〜１０００オングストロームで
あるものが好ましい。また、プラズマ処理の好ましい条
件は以下のとおりである。 （１） 電源は高周波コロナ放電、交流グロー放電、直
流プラズマジェット、高周波無極放電から選ばれる一
種。電力は１０ワットから５００ワット。 （２） ガスの成分は、酸素ガスが主体であることが望
ましく、この他に窒素、ヘリウム、アルゴンとの混合ガ
スであってもよい。その場合の混合比は、酸素分圧が１
０％以上であるのがよい。 （３） ガスの滞留時間は１０分から１８０分。 （４） ガス圧力は、０．１Ｔｏｒｒから２．０Ｔｏｒ
ｒ。 これらの条件から外れると、無処理に比べて、処理の効
果がなく、容量増加がないか、過度の表面酸化により、
容量が低下するかのいずれかの結果となる。Here, the carbon material has an interplanar spacing (d 002 ) of the (002) plane of 3.355 by the X-ray wide angle diffraction method.
It is preferably 3.40 angstroms, and the crystallite size (Lc) in the c-axis direction is 200 to 1000 angstroms. The preferable conditions for the plasma treatment are as follows. (1) The power source is a type selected from high frequency corona discharge, AC glow discharge, DC plasma jet, and high frequency non-polar discharge. The power is 10 to 500 watts. (2) The gas component is preferably oxygen gas as a main component, and in addition to this, a mixed gas of nitrogen, helium, and argon may be used. In that case, the mixing ratio is such that the oxygen partial pressure is 1.
It is preferably 0% or more. (3) Gas residence time is 10 to 180 minutes. (4) Gas pressure is from 0.1 Torr to 2.0 Torr
r. If these conditions are not met, there will be no treatment effect and no capacity increase, or excessive surface oxidation, as compared to untreated,
Either result in reduced capacity.
【０００９】[0009]
【作用】本発明によると、プラズマ処理による表面改質
により、主に、炭素表面の親水性が改善される。本発明
により得られる電極中の炭素材料は、従来の炭素負極と
同様に、充電により負極中にリチウムが吸蔵され、放電
すると吸蔵されたリチウムが電解質中にイオンとして放
出される。したがって、充電によりリチウムが金属状で
析出することはなく、デンドライトによる電池の内部短
絡は起こらない。放電電位は金属Ｌｉに較べ約０．１Ｖ
貴であるので、電池電圧の低下も小さい。According to the present invention, the surface modification by the plasma treatment mainly improves the hydrophilicity of the carbon surface. In the carbon material in the electrode obtained by the present invention, as in the conventional carbon negative electrode, lithium is occluded in the negative electrode by charging, and the occluded lithium is released as an ion in the electrolyte when discharged. Therefore, lithium does not deposit in a metallic state due to charging, and an internal short circuit of the battery due to the dendrite does not occur. Discharge potential is about 0.1V compared to metallic Li
Since it is noble, the drop in battery voltage is small.
【００１０】しかも、炭素表面はプラズマ処理により親
水性の高い状態となり、高結晶化炭素材料の持つ高い充
放電容量をより増加させ、電解液などとの接触が良好と
なることから、充放電による容量低下も小さい。さら
に、このような炭素粉末へのプラズマ処理は、工業的に
は負極板に行うことによって、一層その生産性を低下さ
せることなく上記の効果を得ることができる。本発明に
より、従来の炭素材や黒鉛を用いるものに比べて充放電
の電気容量が増大し、しかも電池の充放電サイクル特性
が向上する。In addition, the carbon surface becomes highly hydrophilic by the plasma treatment, which further increases the high charge / discharge capacity of the highly crystallized carbon material and improves the contact with the electrolytic solution. The capacity decrease is also small. Further, such a plasma treatment of the carbon powder is industrially performed on the negative electrode plate, whereby the above effects can be obtained without further lowering the productivity. According to the present invention, the electric capacity for charge and discharge is increased and the charge and discharge cycle characteristics of the battery are improved as compared with the conventional one using a carbon material or graphite.
【００１１】[0011]
【実施例】以下、本発明の実施例を説明する。 ［実施例１］炭素材料には、Ｘ線広角回折法による（０
０２）面の面間隔（ｄ002）が３．３６オングストロー
ムでｃ軸方向の結晶子の大きさ（Ｌｃ）が６００オング
ストロームのものを用いる。この炭素材料粉末にプラズ
マ処理を行う。すなわち、反応器内に炭素粉末を入れ、
真空（０．０１Ｔｏｒｒ）にし、酸素ガスを導入し、高
周波無極放電によりプラズマを発生させる。電力は１０
０ワットである。導入ガスは酸素ガス単独とし、反応器
内でのガスの滞留時間は２０分である。ガス圧力は０．
２Ｔｏｒｒとする。EXAMPLES Examples of the present invention will be described below. [Example 1] The carbon material was analyzed by the X-ray wide-angle diffraction method (0
The surface spacing (d 002 ) of the (02) plane is 3.36 angstroms and the crystallite size (Lc) in the c-axis direction is 600 angstroms. Plasma treatment is performed on this carbon material powder. That is, put carbon powder in the reactor,
A vacuum (0.01 Torr) is applied, oxygen gas is introduced, and plasma is generated by high frequency non-polar discharge. Power is 10
It is 0 watts. The introduced gas was oxygen gas alone, and the residence time of the gas in the reactor was 20 minutes. The gas pressure is 0.
Set to 2 Torr.
【００１２】この炭素質材料の電極としての特性を検討
するため、図１に示す試験セルを作製する。図１におい
て、１は炭素電極であり、上記の炭素粉末１０ｇに対し
て結着剤のポリエチレン粉末１ｇを混合した合剤０．１
ｇを直径１７．５ｍｍの円板に加圧成型したものであ
る。この炭素電極１をケース２の中央に配置し、その上
に微孔性ポリプロピレンからなるセパレータ３をのせ、
電解液を注液する。次いで、内側に直径１７．５ｍｍの
円板状金属Ｌｉ４を張り付け、外周部にポリプロピレン
製ガスケット５を付けた封口板６を組み合わせて封口
し、試験セルとする。なお、電解液には、１モル／ｌの
過塩素酸リチウムを溶解したエチレンカーボネートとジ
メトキシエタンの体積比１：１の混合溶液を用いる。In order to study the characteristics of this carbonaceous material as an electrode, the test cell shown in FIG. 1 is prepared. In FIG. 1, 1 is a carbon electrode, which is a mixture of 0.1 g of polyethylene powder as a binder and 10 g of the above carbon powder.
g is pressure-molded into a disk having a diameter of 17.5 mm. The carbon electrode 1 is arranged in the center of the case 2, and a separator 3 made of microporous polypropylene is placed on the carbon electrode 1.
Inject electrolyte. Next, a disc-shaped metal Li4 having a diameter of 17.5 mm is attached to the inside, and a sealing plate 6 having a polypropylene gasket 5 attached to the outer periphery is combined and sealed to form a test cell. A mixed solution of ethylene carbonate and dimethoxyethane having a volume ratio of 1: 1 in which 1 mol / l of lithium perchlorate is dissolved is used as the electrolytic solution.
【００１３】上記のセルをセル１とし、プラズマ処理し
ない炭素粉末を用いた電極を有するセルをセル２とす
る。これらのセルについて、２ｍＡの定電流で、炭素電
極がＬｉ対極に対して０Ｖになるまでカソード分極（炭
素電極を負極として見る場合には充電に相当）し、次に
炭素電極が１．０Ｖになるまでアノード分極（放電に相
当）する。このカソード分極、アノード分極を繰り返し
行ない、電極特性を評価する。セル１、セル２の１サイ
クル目の充電容量と放電容量、さらに１００サイクル目
の放電容量と容量維持率を表１に示す。The above cell is referred to as cell 1, and the cell having an electrode using carbon powder which is not subjected to plasma treatment is referred to as cell 2. For these cells, at a constant current of 2 mA, cathode polarization (corresponding to charging when the carbon electrode is viewed as a negative electrode) was performed until the carbon electrode became 0 V with respect to the Li counter electrode, and then the carbon electrode was changed to 1.0 V Anodic polarization (corresponds to discharge) until it becomes. By repeating this cathode polarization and anode polarization, the electrode characteristics are evaluated. Table 1 shows the charge and discharge capacities of cells 1 and 2 in the first cycle, and the discharge capacity and capacity retention ratio in the 100th cycle.
【００１４】[0014]
【表１】 [Table 1]
【００１５】１サイクル目の充放電容量はセル２に比べ
てセル１が大きい。セル２は、１００サイクルで非常に
大きな容量低下を示しているが、セル１は容量維持率が
９０％以上である。このように炭素表面にプラズマ処理
を行うことにより、充放電容量を増加させ、充放電サイ
クル特性を改良する効果がある。なお、本実施例ではプ
ラズマ処理に用いたガスは酸素ガスであるが、この他に
水素、窒素、ヘリウム、アルゴンについても同様の効果
が得られる。Cell 1 has a larger charge / discharge capacity in the first cycle than cell 2. The cell 2 shows a very large capacity drop at 100 cycles, but the cell 1 has a capacity retention rate of 90% or more. By performing the plasma treatment on the carbon surface in this manner, the charge / discharge capacity is increased and the charge / discharge cycle characteristics are improved. Although the gas used for the plasma treatment is oxygen gas in this embodiment, the same effect can be obtained with hydrogen, nitrogen, helium, and argon.
【００１６】［実施例２］Ｘ線広角回折法による（００
２）面の面間隔（ｄ002）が３．３５５〜３．４５オン
グストロームでｃ軸方向の結晶子の大きさ（Ｌｃ）が１
００〜１０００オングストロームの炭素粉末にプラズマ
処理を行う。すなわち、電源には直流プラズマジェット
を用い、電力は２００ワットとする。また、導入ガスは
酸素ガスとアルゴンガスとの混合ガスを用い、その酸素
分圧は７０％とする。[Example 2] X-ray wide-angle diffraction method (00
2) The interplanar spacing (d 002 ) is 3.355 to 3.45 angstrom and the crystallite size (Lc) in the c-axis direction is 1
Plasma treatment is performed on the carbon powder of 100 to 1000 angstroms. That is, a direct current plasma jet is used as the power source and the power is 200 watts. A mixed gas of oxygen gas and argon gas is used as the introduction gas, and the oxygen partial pressure thereof is 70%.
【００１７】こうして得られた炭素質材料の電極として
の特性を検討するため、実施例１と全く同様にして図１
に示す構造の試験セルを作製し、実施例１と同じ条件で
充放電をする。本実施例及びプラズマ処理しない炭素粉
末を用いた比較例について、１サイクル目の放電容量と
１００サイクル目の容量維持率を表２に示す。In order to study the characteristics of the carbonaceous material thus obtained as an electrode, FIG.
A test cell having the structure shown in is prepared and charged and discharged under the same conditions as in Example 1. Table 2 shows the discharge capacity at the first cycle and the capacity retention rate at the 100th cycle for the present example and the comparative example using the carbon powder not subjected to the plasma treatment.
【００１８】[0018]
【表２】 [Table 2]
【００１９】なお、１００サイクル目のカソード分極が
終了した後、試験セルを分解したが、いずれも金属Ｌｉ
の析出は認められなかった。初期放電容量はｄ002が
３．３５５〜３．４０オングストローム、ｃ軸方向の結
晶子の大きさＬｃが２００〜１０００オングストローム
の範囲で高い値を示す。 ｄ002が３．４５オングストロ
ーム、Ｌｃが１００オングストロームでは、初期放電容
量が小さい。これは炭素の結晶性が不十分なため、この
部分の充放電容量が小さいものとなったと考えられる。
また、Ｌｃが１５００オングストロームの場合には、初
期容量が低下している。これは、結晶性がかなり高いも
のであり、天然黒鉛へのリチウムの侵入が逆に妨げられ
たと考えられる。After the 100th cycle of cathodic polarization was completed, the test cell was disassembled.
No precipitation was observed. The initial discharge capacity has a high value in the range of d 002 of 3.355 to 3.40 angstroms and the crystallite size Lc in the c-axis direction of 200 to 1000 angstroms. When d 002 is 3.45 Å and Lc is 100 Å, the initial discharge capacity is small. It is considered that this is because the crystallinity of carbon was insufficient and the charge / discharge capacity of this portion was small.
Further, when Lc is 1500 angstrom, the initial capacity is lowered. This is because the crystallinity is considerably high, and it is considered that the invasion of lithium into natural graphite was hindered.
【００２０】充放電サイクル試験の結果、比較例では１
００サイクル目の容量維持率が６０％程度であるのに対
して、本実施例のセルは、１００サイクル目の容量維持
率は９０％以上を示している。このようにＸ線広角回折
法による（００２）面の面間隔（ｄ002）が３．３５５
〜３．４０オングストロームでｃ軸方向の結晶子の大き
さ（Ｌｃ）が２００〜１０００オングストロームの条件
を満たす炭素質材料にプラズマ処理をしたものを用いる
ことにより、初期容量が大きく、サイクル特性を高める
効果がある。As a result of the charge / discharge cycle test, 1 was obtained in the comparative example.
The capacity retention ratio at the 00th cycle is about 60%, whereas the capacity retention ratio at the 100th cycle shows 90% or more. Thus, the interplanar spacing (d 002 ) of the (002) plane by the X-ray wide-angle diffraction method is 3.355.
The initial capacity is large and the cycle characteristics are enhanced by using a carbonaceous material which satisfies the condition that the crystallite size (Lc) in the c-axis direction is 200 to 1000 angstroms at ˜3.40 angstroms. effective.
【００２１】［実施例３］本実施例では、炭素電極作製
後にプラズマ処理を施す例について説明する。まず、用
いた負極材料の結晶構造は、Ｘ線広角回折法による（０
０２）面の面間隔（ｄ002）が３．３６オングストロー
ムでｃ軸方向の結晶子の大きさ（Ｌｃ）が６００オング
ストロームである。この炭素質材料の粉末と結着剤のポ
リテトラ弗化エチレン樹脂粉末を重量比１００：５の割
合で混合し、さらに水を加えてペースト状としたものを
銅の芯材に塗布後、１００℃で乾燥する。こうして作製
した負極板の表面にプラズマ処理を行う。すなわち、反
応器内に負極板を入れ、真空（０．０１Ｔｏｒｒ）に
し、酸素ガスを導入し、高周波無極放電によりプラズマ
を発生させる。電源の電力は１００ワットである。導入
ガスは酸素ガス単独とし、反応器内でのガスの滞留時間
は２０分、ガス圧力は０．２Ｔｏｒｒとする。[Embodiment 3] In this embodiment, an example in which plasma treatment is performed after the carbon electrode is manufactured will be described. First, the crystal structure of the negative electrode material used is (0
The interplanar spacing (d 002 ) of the (02) plane is 3.36 angstroms, and the crystallite size (Lc) in the c-axis direction is 600 angstroms. This carbonaceous material powder and polytetrafluoroethylene resin powder as a binder were mixed at a weight ratio of 100: 5, and water was further added to form a paste, which was then applied to a copper core material at 100 ° C. To dry. Plasma treatment is performed on the surface of the negative electrode plate thus manufactured. That is, a negative electrode plate is placed in the reactor, a vacuum (0.01 Torr) is applied, oxygen gas is introduced, and plasma is generated by high frequency non-polar discharge. The power supply has a power of 100 watts. The introduced gas is oxygen gas alone, the residence time of the gas in the reactor is 20 minutes, and the gas pressure is 0.2 Torr.
【００２２】上記のようにして得た炭素電極の特性を検
討するため、図２に示すような構造の円筒形電池を組み
立てる。正極活物質としてはＬｉＭｎ2Ｏ4を用い、導電
剤のアセチレンブラックと結着剤のポリ弗化エチレン樹
脂を重量比１００：５：５の割合で混合し、水を加えて
ペースト状としたものをチタンの芯材に塗布後、乾燥し
正極とする。ＬｉＭｎ2Ｏ4の重量は５ｇである。セパレ
ータには微孔性ポリプロピレンを用いる。電極体はスポ
ット溶接にて取り付けた芯材と同材質の正極リード１４
を有する正極板１１と、負極リード１５を有する負極板
１２との間に両極板より幅の広い帯状のセパレータ１３
を介在して全体を渦巻状に卷回して構成する。さらに、
上記電極体の上下それぞれにポリプロピレン製の絶縁板
１６、１７を配して電槽１８に挿入し、電槽１８の上部
に段部を形成させた後、非水電解液として、１モル／ｌ
の過塩素酸リチウムを溶解したエチレンカーボネートと
ジメトキシエタンの体積比１：１の混合溶液を注入し、
正極端子２０を設けたポリプロピレン製封口板１９で密
閉して電池とする。In order to study the characteristics of the carbon electrode obtained as described above, a cylindrical battery having a structure as shown in FIG. 2 is assembled. LiMn 2 O 4 was used as the positive electrode active material, and acetylene black as the conductive agent and polyfluorinated ethylene resin as the binder were mixed at a weight ratio of 100: 5: 5, and water was added to form a paste. Is applied to a titanium core material and then dried to obtain a positive electrode. The weight of LiMn 2 O 4 is 5 g. Microporous polypropylene is used for the separator. The electrode body is a positive electrode lead 14 made of the same material as the core material attached by spot welding.
Between the positive electrode plate 11 having the electrode and the negative electrode plate 12 having the negative electrode lead 15.
The whole is wound in a spiral shape with the interposition of. further,
Insulating plates 16 and 17 made of polypropylene are placed on the upper and lower sides of the electrode body, respectively, and inserted into a battery case 18 to form a step on the upper part of the battery case 18, and then as a non-aqueous electrolyte, 1 mol / l
Injecting a mixed solution of ethylene carbonate and dimethoxyethane in a volume ratio of 1: 1 in which lithium perchlorate is dissolved,
The battery is sealed with a polypropylene sealing plate 19 provided with a positive electrode terminal 20.
【００２３】また、プラズマ処理を行わない負極板を用
いて同様に構成した円筒形電池を比較例とする。これら
の電池について、充放電電流０．５ｍＡ／ｃｍ2、電圧
範囲４．３Ｖから３．０Ｖの間で定電流充放電すること
により、充放電試験をする。表３に、１サイクル目およ
び１００サイクル目の放電容量と容量維持率を示す。Further, a cylindrical battery similarly constructed by using a negative electrode plate which is not subjected to plasma treatment will be taken as a comparative example. A charging / discharging test is performed on these batteries by performing constant current charging / discharging at a charging / discharging current of 0.5 mA / cm 2 and a voltage range of 4.3V to 3.0V. Table 3 shows the discharge capacity and the capacity retention rate at the first cycle and the 100th cycle.
【００２４】[0024]
【表３】 [Table 3]
【００２５】比較例の電池は、サイクルにともない非常
に大きな容量低下を示す。一方、本実施例の電池は容量
維持率が高く、９０％以上である。このように炭素負極
板の表面にプラズマ処理を行うことにより、初期容量を
大きくし、サイクルにともなう容量低下を抑制する効果
がある。なお、実施例では正極として、ＬｉＭｎ2Ｏ4に
ついて説明したが、本発明による負極は、ＬｉＣｏ
Ｏ2、ＬｉＮｉＯ2、ＬｉＦｅＯ2、γ型ＬｉＶ2Ｏ5など
をはじめとする充電放電に対して可逆性を有する正極と
組み合わせた場合にも同様の効果があることは言うまで
もない。The batteries of the comparative examples show a very large decrease in capacity with cycling. On the other hand, the battery of this example has a high capacity retention rate of 90% or more. By thus performing the plasma treatment on the surface of the carbon negative electrode plate, there is an effect that the initial capacity is increased and the capacity decrease due to the cycle is suppressed. In addition, although LiMn 2 O 4 was described as the positive electrode in the examples, the negative electrode according to the present invention is made of LiCo 2.
It goes without saying that the same effect can be obtained when combined with a positive electrode having reversibility for charge and discharge, such as O 2 , LiNiO 2 , LiFeO 2 , and γ-type LiV 2 O 5 .
【００２６】[0026]
【発明の効果】以上述べたように、本発明によれば、高
エネルギー密度で、デンドライトによる短絡のない、サ
イクル寿命に優れた非水電解質二次電池を与える負極を
得ることができる。As described above, according to the present invention, it is possible to obtain a negative electrode which has a high energy density, does not cause a short circuit due to dendrites, and provides a non-aqueous electrolyte secondary battery having an excellent cycle life.
【図１】本発明の実施例に用いた試験セルの縦断面図で
ある。FIG. 1 is a vertical sectional view of a test cell used in an example of the present invention.
【図２】本発明の実施例に用いた円筒形電池の縦断面図
である。FIG. 2 is a vertical sectional view of a cylindrical battery used in an example of the present invention.
１ 実施例の電極 ２ ケース ３ セパレータ ４ 金属Ｌｉ ５ ガスケット ６ 封口板 １１ 正極 １２ 負極 １３ セパレータ １４ 正極リード板 １５ 負極リード板 １６ 上部絶縁板 １７ 下部絶縁板 １８ 電槽 １９ 封口板 ２０ 正極端子 DESCRIPTION OF SYMBOLS 1 Electrode of Example 2 Case 3 Separator 4 Metal Li 5 Gasket 6 Sealing plate 11 Positive electrode 12 Negative electrode 13 Separator 14 Positive electrode lead plate 15 Negative electrode lead plate 16 Upper insulating plate 17 Lower insulating plate 18 Battery case 19 Sealing plate 20 Positive electrode terminal
───────────────────────────────────────────────────── フロントページの続き (72)発明者 伊藤 修二 大阪府門真市大字門真1006番地 松下電器 産業株式会社内 (72)発明者 豊口 ▲吉▼徳 大阪府門真市大字門真1006番地 松下電器 産業株式会社内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shuji Ito 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor, Toyokuchi ▲ Yoshi ▼ 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. In the company
Claims (3)
素粉末を含む電極合剤を成形するか集電体に塗布または
充填して電極を形成することを特徴とする非水電解質二
次電池用負極の製造法。1. A negative electrode for a non-aqueous electrolyte secondary battery, comprising forming an electrode by molding or coating or filling an electrode mixture containing at least a binder and plasma-treated carbon powder. Manufacturing method.
合剤を成形するか集電体に塗布または充填して電極を形
成する工程と、得られた電極の表面にプラズマ処理を行
う工程を有することを特徴とする非水電解質二次電池用
負極の製造法。2. A step of forming an electrode by molding or coating or filling an electrode mixture containing at least a binder and carbon powder, and a step of performing plasma treatment on the surface of the obtained electrode. A method for producing a negative electrode for a non-aqueous electrolyte secondary battery, which comprises:
（００２）面の面間隔が３．３５５〜３．４０オングス
トロームであり、ｃ軸方向の結晶子の大きさ（Ｌｃ）が
２００〜１０００オングストロームである請求項１また
は２に記載の非水電解質二次電池用負極の製造法。3. The carbon powder has a (002) plane spacing of 3.355 to 3.40 angstroms and a crystallite size (Lc) of 200 to 200 in the c-axis direction according to a wide-angle X-ray diffraction method. It is 1000 angstrom, The manufacturing method of the negative electrode for non-aqueous electrolyte secondary batteries of Claim 1 or 2.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5253425A JPH07105938A (en) | 1993-10-08 | 1993-10-08 | Manufacture of negetive electrode for non-aqueous electrolyte secondary battery |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5253425A JPH07105938A (en) | 1993-10-08 | 1993-10-08 | Manufacture of negetive electrode for non-aqueous electrolyte secondary battery |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH07105938A true JPH07105938A (en) | 1995-04-21 |
Family
ID=17251221
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5253425A Pending JPH07105938A (en) | 1993-10-08 | 1993-10-08 | Manufacture of negetive electrode for non-aqueous electrolyte secondary battery |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH07105938A (en) |
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1998040920A3 (en) * | 1997-03-12 | 1998-11-26 | Tno | Method for manufacturing a bipolar plate |
| JPH1131510A (en) * | 1997-07-11 | 1999-02-02 | Mitsubishi Chem Corp | Lithium secondary battery |
| WO2000062358A1 (en) * | 1999-04-08 | 2000-10-19 | Matsushita Electric Industrial Co., Ltd. | Rechargeable battery using nonaqueous electrolyte |
| JP2004253379A (en) * | 2003-01-29 | 2004-09-09 | Jfe Chemical Corp | Negative electrode material and negative electrode for lithium-ion secondary battery, and lithium-ion secondary battery |
| JP2004265733A (en) * | 2003-02-28 | 2004-09-24 | Tdk Corp | Manufacturing method of electrode and manufacturing method of battery |
| KR100477737B1 (en) * | 1998-10-12 | 2005-06-08 | 삼성에스디아이 주식회사 | Manufacturing Method of Electrode for Lithium Secondary Battery_ |
| KR100496279B1 (en) * | 1998-10-22 | 2005-09-09 | 삼성에스디아이 주식회사 | Method of making plate for lithum secondary battery |
| JP2007035552A (en) * | 2005-07-29 | 2007-02-08 | Toyota Motor Corp | Electrode for lithium secondary battery |
| JP2015225792A (en) * | 2014-05-29 | 2015-12-14 | 日立マクセル株式会社 | Negative electrode and lithium secondary battery using the same |
| WO2017111132A1 (en) * | 2015-12-25 | 2017-06-29 | 富士フイルム株式会社 | All-solid secondary battery, particles for all-solid secondary batteries, solid electrolyte composition for all-solid secondary batteries, electrode sheet for all-solid secondary batteries, and production methods therefor |
-
1993
- 1993-10-08 JP JP5253425A patent/JPH07105938A/en active Pending
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1998040920A3 (en) * | 1997-03-12 | 1998-11-26 | Tno | Method for manufacturing a bipolar plate |
| JPH1131510A (en) * | 1997-07-11 | 1999-02-02 | Mitsubishi Chem Corp | Lithium secondary battery |
| KR100477737B1 (en) * | 1998-10-12 | 2005-06-08 | 삼성에스디아이 주식회사 | Manufacturing Method of Electrode for Lithium Secondary Battery_ |
| KR100496279B1 (en) * | 1998-10-22 | 2005-09-09 | 삼성에스디아이 주식회사 | Method of making plate for lithum secondary battery |
| WO2000062358A1 (en) * | 1999-04-08 | 2000-10-19 | Matsushita Electric Industrial Co., Ltd. | Rechargeable battery using nonaqueous electrolyte |
| JP2004253379A (en) * | 2003-01-29 | 2004-09-09 | Jfe Chemical Corp | Negative electrode material and negative electrode for lithium-ion secondary battery, and lithium-ion secondary battery |
| JP2004265733A (en) * | 2003-02-28 | 2004-09-24 | Tdk Corp | Manufacturing method of electrode and manufacturing method of battery |
| JP2007035552A (en) * | 2005-07-29 | 2007-02-08 | Toyota Motor Corp | Electrode for lithium secondary battery |
| JP2015225792A (en) * | 2014-05-29 | 2015-12-14 | 日立マクセル株式会社 | Negative electrode and lithium secondary battery using the same |
| WO2017111132A1 (en) * | 2015-12-25 | 2017-06-29 | 富士フイルム株式会社 | All-solid secondary battery, particles for all-solid secondary batteries, solid electrolyte composition for all-solid secondary batteries, electrode sheet for all-solid secondary batteries, and production methods therefor |
| JPWO2017111132A1 (en) * | 2015-12-25 | 2018-09-20 | 富士フイルム株式会社 | All-solid secondary battery, particles for all-solid secondary battery, solid electrolyte composition for all-solid-state secondary battery, electrode sheet for all-solid-state secondary battery, and production method thereof |
| US10892516B2 (en) | 2015-12-25 | 2021-01-12 | Fujifilm Corporation | All-solid state secondary battery, particles for all-solid state secondary battery, solid electrolyte composition for all-solid state secondary battery, and electrode sheet for all-solid state secondary battery, and methods for manufacturing same |
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