JP2002329495A - Lithium secondary battery and production process thereof - Google Patents
Lithium secondary battery and production process thereofInfo
- Publication number
- JP2002329495A JP2002329495A JP2001134367A JP2001134367A JP2002329495A JP 2002329495 A JP2002329495 A JP 2002329495A JP 2001134367 A JP2001134367 A JP 2001134367A JP 2001134367 A JP2001134367 A JP 2001134367A JP 2002329495 A JP2002329495 A JP 2002329495A
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- Japan
- Prior art keywords
- positive electrode
- lithium secondary
- secondary battery
- sulfur
- polymer
- Prior art date
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Classifications
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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
- 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
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- Compositions Of Macromolecular Compounds (AREA)
- Cell Electrode Carriers And Collectors (AREA)
- Secondary Cells (AREA)
- Battery Electrode And Active Subsutance (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、導電性高分子と硫
黄を主活物質として含む正極を備えたリチウム二次電池
に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lithium secondary battery having a positive electrode containing a conductive polymer and sulfur as main active materials.
【０００２】[0002]
【従来の技術】導電性高分子は導電性ポリアセチレンの
発見以来、軽量な電極材料として注目を集めたが、空気
中で不安定なことや体積当たりのエネルギー密度が低い
ことなどから、比較的安定なポリアセンやポリピロール
が一部の小型電池やコンデンサーの材料として使用され
るに止まっている。一方、硫黄は安価で高エネルギー密
度を有することから、リチウム二次電池の正極活物質と
して古くから注目されてきた材料の１つである（例え
ば、Proceedings of the 6th International Symposium
on Power Sources (1968), UK, Vol.2 p.289-302）。
しかし硫黄を用いた正極は、利用率が低く、金属リチウ
ムに対する電位が２．５Ｖ以下の低電位であり、その
上、自己放電が発生したり、充放電の可逆性が悪いなど
の問題があるので実用化されていない。2. Description of the Related Art Conductive polymers have attracted attention as lightweight electrode materials since the discovery of conductive polyacetylene, but are relatively stable due to instability in air and low energy density per volume. Polyacene and polypyrrole are only used as materials for some small batteries and capacitors. On the other hand, sulfur is one of the materials that has been attracting attention for a long time as a positive electrode active material of a lithium secondary battery because of its low cost and high energy density (for example, Proceedings of the 6th International Symposium).
on Power Sources (1968), UK, Vol.2 p.289-302).
However, the positive electrode using sulfur has a low utilization factor and a low potential of 2.5 V or less with respect to metallic lithium, and further has problems such as self-discharge and poor reversibility of charge and discharge. It has not been put to practical use.
【０００３】これらの問題の主原因は、正極の硫黄が放
電により低分子化して、電解質に対する溶解度が高い硫
化リチウム（Ｌｉ2Ｓ8、Ｌｉ2Ｓ6、Ｌｉ2Ｓ5、Ｌｉ
2Ｓ4、Ｌｉ2Ｓ2、Ｌｉ2Ｓなど）が生成することにあ
る。すなわち、上記の放電生成物が正極合剤内あるいは
電解質中に溶解して拡散すると、これら放電生成物が正
極内の集電ネットワークから孤立して電極反応に関与し
なくなる。そのため、正極の利用率や充放電反応の可逆
性が悪くなり、特に、放電状態で保存した後の充放電特
性（以下、保存特性という）が著しく劣化するものと考
えられる。[0003] The main cause of these problems is that sulfur in the positive electrode is reduced in molecular weight by discharge, and lithium sulfide (Li 2 S 8 , Li 2 S 6 , Li 2 S 5 , Li 2 S 5) having high solubility in the electrolyte is high.
2 S 4 , Li 2 S 2 , Li 2 S, etc.). That is, when the above-mentioned discharge products are dissolved and diffused in the positive electrode mixture or the electrolyte, these discharge products are isolated from the current collection network in the positive electrode and do not participate in the electrode reaction. Therefore, it is considered that the utilization factor of the positive electrode and the reversibility of the charge / discharge reaction are deteriorated, and in particular, the charge / discharge characteristics after storage in a discharge state (hereinafter, referred to as storage characteristics) are significantly deteriorated.
【０００４】これらの特性を改良するために、低分子有
機イオウ化合物（米国特許第４，８３３，０４８号）
や、ポリエチレンオキサイドなどの固体状またはゲル状
のイオン導電性ポリマーと電気化学的に活性な硫黄との
組合せ（米国特許第５，５２３，１７９号）、などの正
極が提案されている。しかし、いずれも作動温度が９０
℃と高温であり、室温での充放電反応の可逆性が不十分
である。In order to improve these properties, low molecular weight organic sulfur compounds (US Pat. No. 4,833,048)
Also, a positive electrode such as a combination of a solid or gel ion conductive polymer such as polyethylene oxide and electrochemically active sulfur (US Pat. No. 5,523,179) has been proposed. However, in all cases, the operating temperature is 90
° C and high temperature, and the reversibility of the charge / discharge reaction at room temperature is insufficient.
【０００５】室温での充放電反応の可逆性を改良するた
め、低分子有機イオウ化合物と導電性高分子の複合正極
（米国特許第５，３２４，５９９号）や、低分子有機イ
オウ化合物、導電性高分子、硫黄、および金属錯体から
なる複合正極（特開平１１−２１４００８号公報、特開
２０００−３４０２２５号公報）などが提案されてい
る。これらの複合正極を用いた電池では、３Ｖ級の高い
放電電圧と、大きな初期放電容量が得られる。しかし、
充放電の可逆性および保存特性が不十分であり、その改
善が今後の大きな課題となっている。In order to improve the reversibility of the charge / discharge reaction at room temperature, a composite cathode of a low molecular organic sulfur compound and a conductive polymer (US Pat. No. 5,324,599), a low molecular organic sulfur compound, Positive electrode composed of a conductive polymer, sulfur and a metal complex (JP-A-11-21408, JP-A-2000-340225) and the like have been proposed. In batteries using these composite positive electrodes, a high 3V-class discharge voltage and a large initial discharge capacity can be obtained. But,
The reversibility and storage characteristics of charge and discharge are insufficient, and improvement thereof is a major issue in the future.
【０００６】[0006]
【発明が解決しようとする課題】本発明は、上記従来の
問題を解決し、高電圧で放電容量が大きく、充放電サイ
クル特性および保存特性が優れたリチウム二次電池を提
供することを目的とする。SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems and to provide a lithium secondary battery having a large discharge capacity at a high voltage, and excellent charge-discharge cycle characteristics and storage characteristics. I do.
【０００７】[0007]
【課題を解決するための手段】本発明のリチウム二次電
池は、数平均分子量３００以上の無定形硫黄および導電
性高分子を含む正極、負極、および非水電解質を備えた
ことを特徴とするものである。導電性高分子は、鎖状構
造のものが好ましく、ポリアセチレン、ポリアセン、ポ
リアニリン、ポリピロール、ポリチオフェン、ポリ−ｐ
−フェニレンスルフィド、およびポリ−ピリジノピリジ
ンよりなる群から選ばれた少なくとも１種類であること
がより好ましい。A lithium secondary battery according to the present invention is provided with a positive electrode, a negative electrode containing amorphous sulfur having a number average molecular weight of 300 or more and a conductive polymer, a negative electrode, and a non-aqueous electrolyte. Things. The conductive polymer preferably has a chain structure, and includes polyacetylene, polyacene, polyaniline, polypyrrole, polythiophene, and poly-p.
More preferably, it is at least one selected from the group consisting of -phenylene sulfide and poly-pyridinopyridine.
【０００８】本発明のリチウム二次電池の製造方法は、
導電性高分子を有機溶媒に溶解させる工程、前記導電性
高分子の有機溶媒溶液に数平均分子量３００以上の無定
形硫黄粉末を分散させる工程、前記無定形硫黄粉末を分
散させた液に導電助剤を分散させて正極ペーストを作製
する工程、前記正極ペーストを正極集電体に塗布する工
程、および前記正極ペーストを塗布した正極集電体を乾
燥して正極板を作製する工程を有することを特徴とする
ものである。The method for manufacturing a lithium secondary battery according to the present invention comprises:
Dissolving the conductive polymer in an organic solvent, dispersing an amorphous sulfur powder having a number average molecular weight of 300 or more in an organic solvent solution of the conductive polymer, and conducting a conductive aid on the liquid in which the amorphous sulfur powder is dispersed. A step of preparing a positive electrode paste by dispersing an agent, a step of applying the positive electrode paste to a positive electrode current collector, and a step of drying the positive electrode current collector to which the positive electrode paste has been applied to prepare a positive electrode plate. It is a feature.
【０００９】[0009]
【発明の実施の形態】硫黄には結晶性のものと無定形の
ものがある。結晶性硫黄としては斜方晶系と単斜晶系の
２種類が知られており、いずれも王冠状のＳ8環状分子
を含んでおり有機溶媒に可溶である。結晶性の硫黄は高
エネルギー密度を期待できるが、充放電の可逆性および
保存性が悪く、これらの改善が困難な正極活物質であ
る。一方、無定形硫黄は、結晶性硫黄よりもエネルギー
密度が若干低いため、正極活物質としては殆ど検討され
ていない。DESCRIPTION OF THE PREFERRED EMBODIMENTS Sulfur is classified into crystalline and amorphous. As the crystalline sulfur are known two types of orthorhombic and monoclinic, both soluble in an organic solvent includes a crown-shaped S 8 cyclic molecule. Crystalline sulfur can be expected to have a high energy density, but has poor reversibility of charge and discharge and storage stability, and is a positive electrode active material which is difficult to improve. On the other hand, since amorphous sulfur has a slightly lower energy density than crystalline sulfur, it is hardly studied as a positive electrode active material.
【００１０】本発明者は、硫黄が高分子量のものほど有
機溶媒に難溶となる特質を有することに着目して、無定
形硫黄の正極活物質としての検討を進めた。その結果、
高分子量の無定形硫黄を正極活物質として用いた場合に
は、放電生成物が比較的大きな分子量を有するため、充
放電のいずれの状態においても正極活物質が非水電解質
に溶解しないことを見出した。さらに本発明者は、この
高分子量の無定形硫黄と導電性高分子を複合させた正極
を検討した結果、充放電の可逆性を改善でき、さらに高
い放電電圧が得られることを見出した。The present inventor has paid attention to the fact that the higher the molecular weight of sulfur, the more difficult it is to dissolve in organic solvents, and has studied the use of amorphous sulfur as a positive electrode active material. as a result,
When high-molecular-weight amorphous sulfur was used as the positive electrode active material, it was found that the positive electrode active material did not dissolve in the non-aqueous electrolyte in any state of charge and discharge because the discharge product had a relatively large molecular weight. Was. Further, the present inventor has studied a positive electrode in which amorphous sulfur having a high molecular weight and a conductive polymer are combined, and as a result, has found that reversibility of charge and discharge can be improved and a higher discharge voltage can be obtained.
【００１１】本発明のリチウム二次電池は、数平均分子
量３００以上の無定形硫黄（以下、高分子量無定形硫黄
という）と導電性高分子で主に構成された正極を用いる
ものである。本発明の正極においては、高分子量無定形
硫黄と導電性高分子との双方の分子が絡みあって複合化
されることにより、リチウム負極に対して３〜４Ｖの高
い放電電位を得ることができる。その理由は定かではな
いが、硫黄分子がポリチオレートアニオンとして導電性
高分子にドーピングされた状態で複合化されることに起
因するものと推測される。また、本発明において用いる
無定形硫黄は分子量が大きいものほど、導電性高分子と
絡み易く、さらに放電生成物の非水電解質に対する溶解
度を低下させる効果が高い。The lithium secondary battery of the present invention uses a positive electrode mainly composed of amorphous sulfur having a number average molecular weight of 300 or more (hereinafter referred to as high molecular weight amorphous sulfur) and a conductive polymer. In the positive electrode of the present invention, a high discharge potential of 3 to 4 V can be obtained with respect to the lithium negative electrode because both high molecular weight amorphous sulfur and the conductive polymer are entangled and complexed. . The reason for this is not clear, but it is presumed to be due to the fact that the sulfur molecule is compounded as a polythiolate anion doped in the conductive polymer. The amorphous sulfur used in the present invention has a higher molecular weight, is more likely to be entangled with the conductive polymer, and has a higher effect of lowering the solubility of the discharge product in the nonaqueous electrolyte.
【００１２】さらに、硫黄分子がドーピングされた導電
性高分子はその導電性が一層高まり、正極内での分子レ
ベルの電子伝導経路を形成するので、電荷移動すなわち
酸化還元反応を円滑に進行させる。これらの効果は、数
平均分子量が３００以上、好ましくは５００以上連なっ
た高分子量を有する無定形硫黄を用いた場合に顕著であ
る。無定形硫黄にはゴム状硫黄と鎖状硫黄があり、鎖状
硫黄は導電性高分子と特に絡み易いので、大きな複合効
果が得られ、正極の高電位化および導電性向上のために
有用である。Further, the conductivity of the conductive polymer doped with sulfur molecules is further enhanced, and a molecular level electron conduction path is formed in the positive electrode, so that the charge transfer, that is, the oxidation-reduction reaction proceeds smoothly. These effects are remarkable when amorphous sulfur having a number average molecular weight of 300 or more, preferably 500 or more and having a high molecular weight is used. Amorphous sulfur includes rubber-like sulfur and chain-like sulfur.Since chain-like sulfur is particularly easily entangled with a conductive polymer, a large composite effect is obtained, which is useful for increasing the potential of the positive electrode and improving conductivity. is there.
【００１３】以上のように、本発明により、正極の放電
生成物の非水電解質に対する溶解度を効果的に低下させ
ることができるので、放電生成物を正極の集電ネットワ
ーク内に固定することができる。さらに、無定形硫黄と
導電性高分子との複合効果により、高い放電電圧を得る
ことができる。その結果、充放電特性および保存特性が
優れ、高電圧で高エネルギー密度を有するリチウム二次
電池を提供できる。As described above, according to the present invention, the solubility of the discharge product of the positive electrode in the nonaqueous electrolyte can be effectively reduced, so that the discharge product can be fixed in the current collection network of the positive electrode. . Furthermore, a high discharge voltage can be obtained by the combined effect of amorphous sulfur and a conductive polymer. As a result, a lithium secondary battery having excellent charge / discharge characteristics and storage characteristics, and having a high voltage and a high energy density can be provided.
【００１４】本発明における正極活物質としての無定形
硫黄は、電池の充放電や保存によって様々な硫化リチウ
ムなどに変化した状態においても、非水電解質に対する
溶解度が小さいことが必要である。従って、エチレンカ
ーボネートとジエチルカーボネートの混合溶媒など電解
質の溶媒に用いられる一般的な有機溶媒への無定形硫黄
の溶解度を単に調べるのみでは、正極活物質としての適
性を適切に評価できない。The amorphous sulfur as the positive electrode active material in the present invention needs to have low solubility in the non-aqueous electrolyte even in a state changed to various lithium sulfides due to charge and discharge and storage of the battery. Therefore, the suitability as a positive electrode active material cannot be properly evaluated by merely examining the solubility of amorphous sulfur in a general organic solvent used as a solvent for an electrolyte such as a mixed solvent of ethylene carbonate and diethyl carbonate.
【００１５】本発明における高分子量無定形硫黄を適切
に評価する手段を見出すために、本発明者は分子量が異
なる種々の無定形硫黄の各種溶媒への溶解度を調べ、こ
れら無定形硫黄と導電性高分子の複合正極を用いた電池
の特性との相関性を検討した。その結果、二硫化炭素に
対する溶解度と電池特性との間に顕著な相関性があるこ
とを見出した。In order to find a means for appropriately evaluating high molecular weight amorphous sulfur in the present invention, the present inventor examined the solubility of various types of amorphous sulfur having different molecular weights in various solvents, and determined the solubility of the amorphous sulfur and the conductivity. The correlation with the characteristics of the battery using the polymer composite cathode was studied. As a result, they found that there was a remarkable correlation between the solubility in carbon disulfide and the battery characteristics.
【００１６】さらに検討を進めた結果、二硫化炭素に対
する２５℃での溶解度が２ｇ／１００ｃｃを越える無定
形硫黄を用いた電池では、自己放電が大きくなることが
明らかになった。このことから、本発明における高分子
量無定形硫黄は、二硫化炭素に対する２５℃での溶解度
が２ｇ／１００ｃｃ以下であるものが好ましいことを見
出した。As a result of further study, it has been found that self-discharge is increased in a battery using amorphous sulfur whose solubility in carbon disulfide at 25 ° C. exceeds 2 g / 100 cc. From this, it has been found that the high-molecular-weight amorphous sulfur in the present invention preferably has a solubility in carbon disulfide at 25 ° C. of 2 g / 100 cc or less.
【００１７】高分子量無定形硫黄としては、４５０〜７
００℃で気化させた硫黄を、例えば水冷ロールなどによ
り５０℃以下に急冷して作製したものを用いた場合に、
本発明の顕著な効果が得られる。この場合の原料硫黄と
しては、結晶性硫黄や低分子量の無定形硫黄を用いるこ
とができる。高分子量無定形硫黄は、正極内に均一に分
散させるために、平均粒径１０μｍ以下の微粒子状のも
のが好ましい。As the high molecular weight amorphous sulfur, 450 to 7
When using sulfur vaporized at 00 ° C., for example, quenched to 50 ° C. or less by a water-cooled roll or the like,
The remarkable effects of the present invention can be obtained. In this case, as the raw material sulfur, crystalline sulfur or low molecular weight amorphous sulfur can be used. The high molecular weight amorphous sulfur is preferably in the form of fine particles having an average particle diameter of 10 μm or less in order to uniformly disperse it in the positive electrode.
【００１８】本発明で用いる導電性高分子は、一般的に
化学重合法または電解重合法により作製される。これら
のうち、複雑に架橋した構造体である電解重合法による
導電性高分子よりも、化学重合法による鎖状構造の導電
性高分子が、高分子量無定形硫黄と絡み合って複合化し
易いので、高い放電電圧が得られる。このことから、本
発明で用いる導電性高分子は、鎖状構造を有するものが
好ましい。The conductive polymer used in the present invention is generally produced by a chemical polymerization method or an electrolytic polymerization method. Of these, a conductive polymer having a chain structure formed by a chemical polymerization method is more easily entangled with high-molecular-weight amorphous sulfur than a conductive polymer formed by an electropolymerization method, which is a complex crosslinked structure, and is thus easily complexed. A high discharge voltage is obtained. For this reason, the conductive polymer used in the present invention preferably has a chain structure.
【００１９】導電性高分子としては、ポリアセチレン、
ポリアセン、ポリアニリン、ポリピロール、ポリチオフ
ェン、ポリ−ｐ−フェニレンスルフィド、ポリピリジノ
ピリジンなどを用いることができる。なかでも、ポリア
ニリン系の鎖状導電性高分子が好ましい。特に、キノン
ジイミン構造とフェニレンジアミン構造がブロックコポ
リマー的に連結したタイプのものが好ましい。これは、
このタイプの導電性高分子のポリマー鎖間に水素結合が
形成されにくいので、無定形硫黄とさらに絡まり易くな
り、電荷移動が効率的に行われるためである。As the conductive polymer, polyacetylene,
Polyacene, polyaniline, polypyrrole, polythiophene, poly-p-phenylene sulfide, polypyridinopyridine, and the like can be used. Among them, a polyaniline-based chain conductive polymer is preferable. In particular, a type in which a quinone diimine structure and a phenylenediamine structure are linked in a block copolymer manner is preferable. this is,
This is because hydrogen bonds are not easily formed between the polymer chains of the conductive polymer of this type, so that they are more likely to be entangled with amorphous sulfur, and charge transfer is efficiently performed.
【００２０】本発明は、正極の集電ネットワークを強化
するために、高分子量無定形硫黄と導電性高分子に加え
て、導電助剤として金属あるいは炭素の粉末を添加する
ことが好ましい。これにより、充放電レート特性および
充放電サイクル特性をさらに改良することができる。金
属粉末としては、粒径１μｍ以下の銅、銀、ニッケル、
コバルト、鉄、亜鉛、および錫よりなる群から選ばれた
少なくとも１種類が好ましい。金属粉末は単なる導電助
剤としての作用以外に、導電性高分子と高分子量無定形
硫黄の分子鎖間の架橋剤として分子鎖間結合を強化する
作用を有する。また、炭素粉末は正極の電子電導性と機
械的強度を向上させる効果を有することから、安定な充
放電特性を得るために有用である。In the present invention, in order to strengthen the current collection network of the positive electrode, it is preferable to add a metal or carbon powder as a conductive aid in addition to the high molecular weight amorphous sulfur and the conductive polymer. Thereby, the charge / discharge rate characteristics and the charge / discharge cycle characteristics can be further improved. As the metal powder, copper, silver, nickel having a particle size of 1 μm or less,
At least one selected from the group consisting of cobalt, iron, zinc and tin is preferred. The metal powder has a function of strengthening the intermolecular bond as a cross-linking agent between the conductive polymer and the high molecular weight amorphous sulfur in addition to the function as a mere conductive aid. In addition, carbon powder has an effect of improving the electron conductivity and mechanical strength of the positive electrode, and thus is useful for obtaining stable charge and discharge characteristics.
【００２１】高分子量無定形硫黄と導電性高分子の正極
中の含有比率は、重量比で８０〜５０：５０〜２０が好
ましい。導電性高分子の含有比率が５０を越える場合や
高分子量無定形硫黄の含有比率が５０未満の場合には正
極の放電容量が小さくなる。また、高分子量無定形硫黄
の含有比率が８０を越える場合や導電性高分子の含有比
率が２０未満の場合には、前記の複合効果が不十分なた
め、３Ｖ級の一段の放電曲線が得られず、一段目の４〜
３Ｖから約２Ｖに急速に電圧降下する二段の放電曲線を
示す。The content ratio of the high molecular weight amorphous sulfur to the conductive polymer in the positive electrode is preferably 80 to 50:50 to 20 by weight. When the content ratio of the conductive polymer exceeds 50 or when the content ratio of the high molecular weight amorphous sulfur is less than 50, the discharge capacity of the positive electrode becomes small. When the content ratio of the high molecular weight amorphous sulfur exceeds 80 or when the content ratio of the conductive polymer is less than 20, the above-mentioned combined effect is insufficient, so that a 3V-class one-step discharge curve is obtained. Not possible, 4th of the first stage
2 shows a two-stage discharge curve in which the voltage rapidly drops from 3V to about 2V.
【００２２】正極に導電助剤を含有させる場合には、高
分子量無定形硫黄と導電性高分子と導電助剤の含有比率
は、重量比で８０〜３０：５０〜１０：２０〜１が好ま
しく、７５〜４５：４０〜２０：１０〜２とするのがさ
らに好ましい。導電助剤の含有比率が２０を越えると正
極活物質の充填容量が小さくなり、１未満では正極の導
電性を高める効果が不十分である。When the positive electrode contains a conductive auxiliary, the content ratio of high molecular weight amorphous sulfur, conductive polymer and conductive auxiliary is preferably from 80 to 30:50 to 10:20 to 1 by weight. , 75-45: 40-20: 10-2. If the content of the conductive additive exceeds 20, the filling capacity of the positive electrode active material becomes small, and if it is less than 1, the effect of increasing the conductivity of the positive electrode is insufficient.
【００２３】正極集電体の材料は、正極の充電電位が４
Ｖ前後の高い電位となることから、特に高電位が印加さ
れた状態での耐食性に優れたものが好ましい。その材料
としては、アルミニウム、チタン、フェライト系ステン
レス鋼などが好ましい。さらに正極合剤に直接に接合す
る集電体の表面には、カーボンブラックなどの炭素粉末
とバインダー樹脂などからなる表面層を設けることが好
ましい。これにより、正極合剤と集電体の接合界面の安
定した電気的導通が得られ、正極の利用率を向上させる
ことができる。The material of the positive electrode current collector is such that the charging potential of the positive electrode is 4
Since a high potential of about V is obtained, a material having excellent corrosion resistance particularly in a state where a high potential is applied is preferable. As the material, aluminum, titanium, ferritic stainless steel and the like are preferable. Further, it is preferable to provide a surface layer made of carbon powder such as carbon black and a binder resin on the surface of the current collector directly bonded to the positive electrode mixture. As a result, stable electrical conduction at the bonding interface between the positive electrode mixture and the current collector is obtained, and the utilization rate of the positive electrode can be improved.
【００２４】本発明は、ゲル状のポリマー電解質を用い
たリチウム二次電池に適用した場合に特に効果的であ
る。ゲル状のポリマー電解質とは、架橋高分子が液状の
有機電解質により膨潤した状態のものを指す。このリチ
ウム二次電池には、セパレータを介して正負極を対向さ
せて電極群を捲回または積層し、これに液状のポリマー
電解質を注液して含浸させた後に電解質をゲル化させた
電池と、セパレータを使用せずに、ゲル状のポリマー自
体にセパレータの役割をさせる電池がある。The present invention is particularly effective when applied to a lithium secondary battery using a gel polymer electrolyte. The gel polymer electrolyte refers to a state in which a crosslinked polymer is swollen by a liquid organic electrolyte. This lithium secondary battery has a battery in which a positive electrode and a negative electrode are opposed to each other with a separator interposed therebetween, and an electrode group is wound or laminated, and a liquid polymer electrolyte is injected into the lithium secondary battery to impregnate it, and then the electrolyte is gelled. There is a battery in which a gel polymer itself functions as a separator without using a separator.
【００２５】ポリマー電解質には、ポリフッ化ビニリデ
ン系、ポリアクリロニトリル系、ポリエーテル系、およ
びポリエステル系などがある。本発明において好ましい
ポリマー電解質は、主鎖としてエステル骨格、エーテル
骨格、およびアクリロニトリル骨格のいずれかを有する
ポリマーを含むものである。The polymer electrolyte includes polyvinylidene fluoride, polyacrylonitrile, polyether, and polyester. Preferred polymer electrolytes in the present invention are those containing a polymer having any of an ester skeleton, an ether skeleton, and an acrylonitrile skeleton as a main chain.
【００２６】上記の内、エステル骨格を有するポリマー
を含むポリマー電解質は、エチルアセテートあるいはエ
チレンカーボネイトを繰り返し単位とし、その末端にア
クリレートあるいはメタクリレート基を有するオリゴマ
ーを、例えばエチレンカーボネイトとプロピレンカーボ
ネイトの混合溶媒などの有機溶媒にリチウム塩を溶解し
た有機電解質中で重合させることにより得られる。エー
テル骨格を有するポリマーを含むポリマー電解質は、エ
チレンオキサイドやプロピレンオキサイドを主鎖にもつ
ものを、液状の有機電解質中で重合させることにより得
られる。アクリロニトリル骨格を有するポリマーを含む
ポリマー電解質は、アクリロニトリル・ブタジエンゴム
やアクリロニトリル・ブタジエン・スチレン樹脂などの
アクリロニトリル系共重合体を、液状の有機電解質に溶
解させ、約１４０℃に加熱した後に急冷することで得ら
れる。上記の各ポリマー電解質は液状の有機電解質中で
重合させたゲル状の電解質であるが、これに限定するこ
となく、有機電解質を含まない固体状のイオン伝導性ポ
リマーを単独で電解質として用いることもできる。Among the above, the polymer electrolyte containing a polymer having an ester skeleton is an oligomer having ethyl acetate or ethylene carbonate as a repeating unit and having an acrylate or methacrylate group at its terminal, for example, a mixed solvent of ethylene carbonate and propylene carbonate. By polymerizing in an organic electrolyte in which a lithium salt is dissolved in an organic solvent. A polymer electrolyte containing a polymer having an ether skeleton is obtained by polymerizing a polymer having ethylene oxide or propylene oxide in the main chain in a liquid organic electrolyte. A polymer electrolyte containing a polymer having an acrylonitrile skeleton is obtained by dissolving an acrylonitrile-based copolymer such as acrylonitrile-butadiene rubber or acrylonitrile-butadiene-styrene resin in a liquid organic electrolyte, heating to about 140 ° C., and then rapidly cooling. can get. Each of the above polymer electrolytes is a gel electrolyte polymerized in a liquid organic electrolyte, but is not limited thereto, and a solid ion conductive polymer containing no organic electrolyte may be used alone as the electrolyte. it can.
【００２７】本発明においては、上記のポリマー電解質
のうち、主鎖としてエステル骨格を有し、側鎖に１級ア
ルキルアミノ基を有するアクリレートポリマーまたはメ
タクリレートポリマーを含むものが特に好ましい。これ
は、１級アルキルアミノ基の側鎖を有するポリマーは導
電性高分子との相溶性が高くなり、正極とポリマー電解
質界面の良好な接合状態が得られるためである。このう
ち、ゲル状のポリマー電解質は、有機溶媒にリチウム塩
を溶解させた液状の有機電解質に、前記アクリレートポ
リマーまたはメタクリレートポリマー、および重合開始
剤を溶解させ、これを７０℃前後に加熱することで得ら
れる。In the present invention, among the above-mentioned polymer electrolytes, those containing an acrylate polymer or a methacrylate polymer having an ester skeleton as a main chain and having a primary alkylamino group in a side chain are particularly preferable. This is because the polymer having the side chain of the primary alkylamino group has high compatibility with the conductive polymer, and a good bonding state between the positive electrode and the polymer electrolyte interface can be obtained. Among them, the gel polymer electrolyte is obtained by dissolving the acrylate polymer or methacrylate polymer and the polymerization initiator in a liquid organic electrolyte obtained by dissolving a lithium salt in an organic solvent, and heating the mixture to about 70 ° C. can get.
【００２８】本発明における非水電解質としては、上記
のポリマー電解質以外に、液状の有機電解質を用いるこ
ともできる。液状の有機電解質は、例えばエチレンカー
ボネイト、プロピレンカーボネイト、ジメチルカーボネ
イト、エチルメチルカーボネイトなどの有機溶媒に、例
えば６フッ化リン酸リチウム（ＬｉＰＦ6）、４フッ化
ホウ酸リチウム（ＬｉＢＦ4）、およびリチウムビスペ
ンタフロロエチルスルホン酸イミド（Ｌｉ(Ｃ2Ｆ5Ｓ
Ｏ2)2Ｎ）などのリチウム塩を溶解させて調製すること
ができる。また、本発明の非水電解質としては、有機系
あるいは無機系の固体電解質を用いることもできる。As the non-aqueous electrolyte in the present invention, a liquid organic electrolyte may be used in addition to the above-mentioned polymer electrolyte. The liquid organic electrolyte may be, for example, an organic solvent such as ethylene carbonate, propylene carbonate, dimethyl carbonate, and ethyl methyl carbonate, for example, lithium hexafluorophosphate (LiPF 6 ), lithium tetrafluoroborate (LiBF 4 ), and lithium Bispentafluoroethylsulfonimide (Li (C 2 F 5 S
It can be prepared by dissolving a lithium salt such as O 2 ) 2 N). Further, as the non-aqueous electrolyte of the present invention, an organic or inorganic solid electrolyte can be used.
【００２９】本発明の正極活物質は重量当たりのエネル
ギー密度が高いという特徴を有するので、重量当たりの
エネルギー密度が高い負極活物質を用いることにより、
軽量でエネルギー密度が高いリチウム二次電池を構成で
きる。その負極活物質としては、一般式Ｌｉ3-xＣｏxＮ
（ここに、０＜ｘ＜１）で表されるリチウム含有複合窒
化物が好ましい。そのなかでも、Ｃｏ置換量ｘが０．２
＜ｘ＜０．６の範囲であるものが特に好ましい。上記の
コバルト添加系以外にも、ニッケル、銅、鉄、マンガン
などの遷移金属を添加したリチウム含有複合窒化物を用
いることができる。これら材料は、高エネルギー密度を
特徴とするＬｉ3Ｎを、充放電サイクルおよび過放電特
性の安定化の観点から改良したものである。Since the positive electrode active material of the present invention has a feature that the energy density per weight is high, by using the negative electrode active material having a high energy density per weight,
A light weight and high energy density lithium secondary battery can be configured. As the negative electrode active material, a general formula Li 3-x Co x N
(Here, a lithium-containing composite nitride represented by 0 <x <1) is preferable. Among them, the Co substitution amount x is 0.2
Those in the range of <x <0.6 are particularly preferred. In addition to the above-mentioned cobalt addition system, a lithium-containing composite nitride to which a transition metal such as nickel, copper, iron, and manganese is added can be used. These materials are obtained by improving Li 3 N, which is characterized by a high energy density, from the viewpoint of stabilization of charge / discharge cycles and overdischarge characteristics.
【００３０】負極活物質として金属リチウム、あるいは
リチウムとアルミニウムなどの合金を用いることによ
り、高電圧で高エネルギー密度のリチウム二次電池を構
成できる。上記以外に、充放電可能な炭素負極、ＴｉＳ
ｎ合金、ＦｅＳｎ合金などを用いた合金負極、あるい
は、Ｓｉ、Ｓｎ、Ａｌ、Ｂ、Ｇｅ、Ｐ、Ｐｂなどの酸化
物またはこれらの元素の複合酸化物などを、単独または
複数を組み合わせた負極活物質を本発明の電池に用いる
ことも可能である。これらのうちで、リチウムを含まな
い負極活物質を用いる場合には、予めリチウムをドーピ
ングしたものを用いるか、あるいは電池内に組み入れた
金属リチウムなどのリチウム供給源により電池内で負極
活物質にリチウムをドーピングする方式を採ればよい。By using metallic lithium or an alloy of lithium and aluminum as the negative electrode active material, a lithium secondary battery having a high voltage and a high energy density can be formed. In addition to the above, chargeable / dischargeable carbon anode, TiS
n-alloy, an alloy negative electrode using an FeSn alloy, or a negative electrode active material in which oxides such as Si, Sn, Al, B, Ge, P, and Pb or composite oxides of these elements are used alone or in combination. Materials can also be used in the battery of the present invention. Among these, when using a negative electrode active material that does not contain lithium, use a lithium-doped negative electrode active material in advance or use lithium as a negative electrode active material in a battery by a lithium supply source such as metallic lithium incorporated in the battery. May be adopted.
【００３１】さらに、本発明のリチウム二次電池の製造
方法は、ポリアニリンなどの導電性高分子をＮ−メチル
−２−ピロリドンなどの有機溶媒に溶解させる工程、こ
の導電性高分子の有機溶媒溶液に高分子量無定形硫黄の
粉末を分散させる工程、この高分子量無定形硫黄の粉末
を分散させた液に導電助剤を分散させて正極ペーストを
作製する工程、この正極ペーストを正極集電体に塗布す
る工程、およびこの正極集電体を乾燥して正極板を作製
する工程を含むものである。Further, in the method of manufacturing a lithium secondary battery according to the present invention, a step of dissolving a conductive polymer such as polyaniline in an organic solvent such as N-methyl-2-pyrrolidone; Dispersing a high molecular weight amorphous sulfur powder into a liquid, dispersing a conductive auxiliary in a liquid in which the high molecular weight amorphous sulfur powder is dispersed, to prepare a positive electrode paste, and applying the positive electrode paste to a positive electrode current collector. The method includes a step of coating and a step of drying the positive electrode current collector to produce a positive electrode plate.
【００３２】正極ペーストの作製に際しては、必要に応
じて、上記導電助剤を分散させる工程の前または後に、
結着剤を混合する工程を設けてもよい。正極板は、厚み
調整や高重点密度化のために、必要に応じてプレスした
り、圧延ローラーで圧延したりしてもよい。その後、必
要に応じて所定の形状に加工して、正極として用いるこ
とができる。本発明の製造方法により、微粒子状の導電
助剤と高分子量無定形硫黄粉末を分子レベルで均一に分
散させた正極が得られ、これを用いて、より優れた特性
のリチウム二次電池を作製することができる。In preparing the positive electrode paste, if necessary, before or after the step of dispersing the conductive auxiliary,
A step of mixing a binder may be provided. The positive electrode plate may be pressed or rolled with a rolling roller as needed for thickness adjustment and high-priority density. Thereafter, it can be processed into a predetermined shape as needed, and used as a positive electrode. According to the production method of the present invention, a positive electrode in which a fine particle-shaped conductive auxiliary agent and a high molecular weight amorphous sulfur powder are uniformly dispersed at a molecular level is obtained, and a lithium secondary battery having more excellent characteristics is produced using the positive electrode. can do.
【００３３】本発明により、積層形、折り畳み式、およ
び捲回式などの電極群構成を有するコイン形電池、円筒
形電池、角形電池、および扁平形電池など様々な形態の
リチウム二次電池を提供することができる。According to the present invention, there are provided various forms of lithium secondary batteries such as coin batteries, cylindrical batteries, prismatic batteries, and flat batteries having an electrode group configuration such as a stacked type, a folded type, and a wound type. can do.
【００３４】[0034]
【実施例】次に、本発明を実施例により詳細に説明す
る。各実施例では、各種正極活物質を用いてコイン形リ
チウム二次電池を作製し、それらの充放電特性、および
放電状態で高温保存した後の容量回復率を評価した。Next, the present invention will be described in detail with reference to examples. In each example, coin-type lithium secondary batteries were manufactured using various positive electrode active materials, and their charge / discharge characteristics and capacity recovery rate after high-temperature storage in a discharged state were evaluated.
【００３５】《実施例１》図１に作製したコイン形リチ
ウム二次電池の縦断面図を示す。まず、アセチレンブラ
ックと変性ポリフッ化ビニリデン（呉羽化学工業（株）
製、＃９１３０）を重量比１：３で混合し、これをＮ−
メチル−２−ピロリドン（以下、ＮＭＰで表す）に分散
させたペーストを、厚み３０μｍのアルミニウム箔に塗
布して乾燥し、厚さ約５μｍのカーボン表面層３を有す
る正極集電体２を作製した。次に、還元脱ドープ状態の
鎖状構造のポリアニリン（日東電工（株）製、アニリー
ド、平均分子量１６０，０００）のＮＭＰ溶液に平均粒
径６μｍの高分子量無定形硫黄を添加して、均一に混合
した。この混合液に、さらにアセチレンブラックを混合
して分散させた後、変性ポリフッ化ビニリデン（呉羽化
学工業（株）製、＃９１３０）のＮＭＰ溶液を混合して
正極ペーストを調製した。正極ペーストは、ポリアニリ
ン：高分子量無定形硫黄：アセチレンブラック：ポリフ
ッ化ビニリデンの重量比が３：５：１：１となるように
調製した。Example 1 FIG. 1 shows a longitudinal sectional view of a coin-type lithium secondary battery manufactured. First, acetylene black and modified polyvinylidene fluoride (Kureha Chemical Industry Co., Ltd.)
# 9130) was mixed at a weight ratio of 1: 3.
A paste dispersed in methyl-2-pyrrolidone (hereinafter referred to as NMP) was applied to an aluminum foil having a thickness of 30 μm and dried to prepare a positive electrode current collector 2 having a carbon surface layer 3 having a thickness of about 5 μm. . Next, a high molecular weight amorphous sulfur having an average particle diameter of 6 μm was added to an NMP solution of a polyaniline having a chain structure in a reduced undoped state (manufactured by Nitto Denko Corporation, Anilead, average molecular weight 160,000), and uniformly added. Mixed. After acetylene black was further mixed and dispersed in the mixed solution, an NMP solution of modified polyvinylidene fluoride (# 9130, manufactured by Kureha Chemical Industry Co., Ltd.) was mixed to prepare a positive electrode paste. The positive electrode paste was prepared such that the weight ratio of polyaniline: high molecular weight amorphous sulfur: acetylene black: polyvinylidene fluoride was 3: 5: 1: 1.
【００３６】高分子量無定形硫黄は、結晶性硫黄を４５
０℃で気化させ、これを２０℃の水冷ロール上で急冷し
て凝固させて作製した粒径６μｍの粉末を用いた。この
無定形硫黄についてＸ線回折等の分析を行った結果、数
平均分子量は８００で、２５℃での二硫化炭素に対する
溶解度は１ｇ／１００ｃｃであった。The high-molecular-weight amorphous sulfur has a crystalline sulfur content of 45%.
A powder having a particle size of 6 μm, which was vaporized at 0 ° C. and rapidly cooled and solidified on a water-cooled roll at 20 ° C., was used. The amorphous sulfur was analyzed by X-ray diffraction or the like. As a result, the number-average molecular weight was 800, and the solubility in carbon disulfide at 25 ° C. was 1 g / 100 cc.
【００３７】次に、アルミニウム箔製の正極集電体２の
カーボン表面層３上に、前記正極ペーストを塗布し、７
０℃の真空中で１２時間乾燥した。これを圧延ローラー
で圧延した後、円形に打ち抜いて直径１８ｍｍ、厚み３
００μｍの正極４を作製した。一方、厚み２００μｍの
金属リチウム板を直径１８ｍｍの円形に打ち抜いた負極
６を、ポリプロピレン製のガスケット８に装着されたス
テンレス鋼製の封口板７に圧着した。Next, the above-mentioned positive electrode paste was applied on the carbon surface layer 3 of the positive electrode current collector 2 made of aluminum foil.
Dried in vacuum at 0 ° C. for 12 hours. After being rolled by a rolling roller, it is punched into a circular shape and has a diameter of 18 mm and a thickness of 3 mm.
A positive electrode 4 of 00 μm was produced. On the other hand, a negative electrode 6 obtained by punching a 200 μm-thick metal lithium plate into a circular shape having a diameter of 18 mm was pressure-bonded to a stainless steel sealing plate 7 mounted on a polypropylene gasket 8.
【００３８】負極６を圧着したガスケット８付き封口板
７の内側に、ポリエチレン微多孔膜（セルガード＃２７
２０、厚み２０μｍ、多孔度５２％）製のセパレータ５
を設置した後、このセパレータ５に液状の有機電解質を
注液して含浸させた。このガスケット８付き封口板７
に、正極４とステンレス鋼製の電池ケース１を被せて封
口し、コイン形電池を作製した。有機電解質には、エチ
レンカーボネイトとエチルメチルカーボネイトとの体積
比１：２の混合溶媒に、ＬｉＰＦ6を１．５ｍｏｌ／ｌ
溶解した溶液を用いた。上記コイン形電池の作製作業
は、全て露点温度−６０℃の雰囲気中で行った。Inside the sealing plate 7 with the gasket 8 to which the negative electrode 6 is pressed, a microporous polyethylene membrane (Celgard # 27)
20, separator having a thickness of 20 μm and a porosity of 52%)
, A liquid organic electrolyte was injected into the separator 5 to impregnate it. Sealing plate 7 with this gasket 8
Then, the positive electrode 4 and a battery case 1 made of stainless steel were covered and sealed to produce a coin-type battery. In the organic electrolyte, 1.5 mol / l of LiPF 6 was added to a mixed solvent of ethylene carbonate and ethyl methyl carbonate in a volume ratio of 1: 2.
The dissolved solution was used. All the operations for manufacturing the coin-shaped battery were performed in an atmosphere having a dew point of -60 ° C.
【００３９】《実施例２》結晶性硫黄を７００℃で気化
させ、これを４０℃の水冷ロール上で急冷して凝固させ
て高分子量無定形硫黄を作製した。この高分子量無定形
硫黄を用いた以外は、実施例１と同様にして図１に示す
コイン形電池を作製した。この無定形硫黄の数平均分子
量は５００で、２５℃での二硫化炭素に対する溶解度は
１．５ｇ／１００ｃｃであった。Example 2 Crystalline sulfur was vaporized at 700 ° C. and rapidly cooled and solidified on a water-cooled roll at 40 ° C. to produce high molecular weight amorphous sulfur. A coin-shaped battery shown in FIG. 1 was produced in the same manner as in Example 1 except that this high-molecular-weight amorphous sulfur was used. This amorphous sulfur had a number average molecular weight of 500 and a solubility in carbon disulfide at 25 ° C. of 1.5 g / 100 cc.
【００４０】《実施例３》結晶性硫黄を８００℃で気化
させ、これを３０℃の水冷ロール上で急冷して凝固させ
て高分子量無定形硫黄を作製した。この高分子量無定形
硫黄を用いた以外は、実施例２と同様にして図１に示す
コイン形電池を作製した。この無定形硫黄の数平均分子
量は３００で、２５℃での二硫化炭素に対する溶解度は
２ｇ／１００ｃｃであった。Example 3 Crystalline sulfur was vaporized at 800.degree. C. and rapidly solidified on a water-cooled roll at 30.degree. C. to coagulate to produce high molecular weight amorphous sulfur. A coin-shaped battery shown in FIG. 1 was produced in the same manner as in Example 2 except that this high-molecular-weight amorphous sulfur was used. This amorphous sulfur had a number average molecular weight of 300 and a solubility in carbon disulfide at 25 ° C. of 2 g / 100 cc.
【００４１】《実施例４》非水電解質として、液状の有
機電解質の代わりにゲル状のポリエステル系のポリマー
電解質を用いた以外は、実施例１と同様にして図１に示
すコイン形電池を作製した。ポリマー電解質は、次のよ
うにして調製した。まず、エチレンカーボネイトとエチ
ルメチルカーボネイトの体積比１：２の混合溶媒に、Ｌ
ｉ(Ｃ2Ｆ5ＳＯ2)2ＮとＬｉＢＦ4をそれぞれ０．５ｍｏ
ｌ／ｌと１ｍｏｌ／ｌ溶解した液状の有機電解質を調製
した。次いで、エステル基を主鎖とし、側鎖にエチルア
ミノエチル基（Ｃ2Ｈ4Ｎ（Ｃ2Ｈ4）Ｈ）を有するジメタ
クリレートに、熱重合開始剤２，２'−アゾビス−２，
４−ジメチルバレロニトリル（和光純薬工業製Ｖ−６
５）を添加したものを、前記液状の有機電解質と混合し
た。前記液状の有機電解質とメタクリレートの重量比を
８５：１５とし、重合開始剤はメタクリレート１００に
対して０．５の重量比で添加した。Example 4 A coin-type battery shown in FIG. 1 was prepared in the same manner as in Example 1, except that a gel-like polyester-based polymer electrolyte was used instead of the liquid organic electrolyte as the non-aqueous electrolyte. did. The polymer electrolyte was prepared as follows. First, L was added to a mixed solvent of ethylene carbonate and ethyl methyl carbonate at a volume ratio of 1: 2.
i (C 2 F 5 SO 2 ) 2 N and LiBF 4 are each 0.5 mol
1 / l and 1 mol / l dissolved organic electrolytes were prepared. Then, an ester group as a main chain, a dimethacrylate having ethylamino ethyl group in the side chain (C 2 H 4 N (C 2 H 4) H), thermal polymerization initiator 2,2'-azobis -2,
4-dimethylvaleronitrile (V-6 manufactured by Wako Pure Chemical Industries, Ltd.)
5) was added and mixed with the liquid organic electrolyte. The weight ratio of the liquid organic electrolyte and methacrylate was 85:15, and the polymerization initiator was added at a weight ratio of 0.5 to 100 of methacrylate.
【００４２】このように調製した液状のポリマー電解質
を実施例１と同様にしてセパレータに含浸させた後、封
口してコイン形電池を作製した。封口後の電池を７０℃
で１時間熱処理し、電池内でメタクリレートを重合させ
てポリマー電解質のゲル化を行い、ポリマーリチウム二
次電池を作製した。The liquid polymer electrolyte thus prepared was impregnated into a separator in the same manner as in Example 1 and then sealed to produce a coin-type battery. 70 ° C after sealed battery
For 1 hour, and polymerized methacrylate in the battery to gel the polymer electrolyte to produce a polymer lithium secondary battery.
【００４３】《実施例５》負極として、金属リチウム箔
の代わりに、リチウム含有複合窒化物Ｌｉ2.6Ｃｏ0.4Ｎ
を主材料とする負極を用いた以外は、実施例４と同様に
してコイン形電池を作製した。Ｌｉ2.6Ｃｏ0.4Ｎは、所
定組成比のリチウム−コバルト合金を銅製容器に入れ、
窒素雰囲気中で３００℃で２４時間保持して得られた黒
灰色の化合物を粉砕して作製した。負極は、Ｌｉ2.6Ｃ
ｏ0.4Ｎ、人造黒鉛、およびポリテトラフルオロエチレ
ンを８５：３：１２の重量比で混合し、これにトルエン
を加えて負極ペーストを調製し、このペーストを銅箔製
集電体上に塗布して乾燥後、圧延し、所定の大きさに打
ち抜いて作製した。Example 5 As a negative electrode, a lithium-containing composite nitride Li 2.6 Co 0.4 N was used instead of a metal lithium foil.
A coin-shaped battery was produced in the same manner as in Example 4, except that a negative electrode mainly composed of was used. Li 2.6 Co 0.4 N, a lithium-cobalt alloy having a predetermined composition ratio is put in a copper container,
A black-gray compound obtained by holding at 300 ° C. for 24 hours in a nitrogen atmosphere was pulverized and produced. The negative electrode is Li 2.6 C
o 0.4 N, artificial graphite, and polytetrafluoroethylene were mixed at a weight ratio of 85: 3: 12, and toluene was added thereto to prepare a negative electrode paste, and this paste was applied on a copper foil current collector. After drying, rolling and punching to a predetermined size were performed.
【００４４】《実施例６》実施例２の正極ペーストに、
さらに平均粒径３０ｎｍの銅微粒子（真空冶金製、Ｃｕ
（５００）ＵＦＰ）をポリアニリンに対して１０重量％
添加して正極ペーストを調製した。この正極ペーストを
用いた以外は実施例２と同様にしてコイン形電池を作製
した。この正極ペースト中の無定形硫黄：ポリアニリ
ン：銅微粒子の配合比は、重量比で６０：３６：４とし
た。Example 6 The positive electrode paste of Example 2
Furthermore, copper fine particles having an average particle diameter of 30 nm (manufactured by vacuum metallurgy, Cu
10% by weight of (500) UFP) based on polyaniline
This was added to prepare a positive electrode paste. A coin battery was manufactured in the same manner as in Example 2 except that this positive electrode paste was used. The compounding ratio of amorphous sulfur: polyaniline: copper fine particles in this positive electrode paste was 60: 36: 4 by weight.
【００４５】《実施例７》カーボン表面層を設けない正
極集電体を用いた以外は、実施例１と同様にしてコイン
形電池を作製した。Example 7 A coin-shaped battery was manufactured in the same manner as in Example 1, except that a positive electrode current collector having no carbon surface layer was used.
【００４６】《実施例８》非水電解質として、実施例１
の液状の有機電解液の代わりにアクリロニトリル系のゲ
ル状のポリマー電解質を用い、導電性高分子として、鎖
状ポリアニリンの代わりに架橋ポリアニリンを用いた。
また、セパレータを用いずに、ゲル状のポリマー電解質
の膜を電解質兼セパレータとして用いた。上記以外は実
施例１と同様にしてコイン形電池を作製した。Example 8 Example 1 was used as a non-aqueous electrolyte.
An acrylonitrile-based gel polymer electrolyte was used in place of the liquid organic electrolyte, and crosslinked polyaniline was used as the conductive polymer instead of chain polyaniline.
Also, a gel polymer electrolyte membrane was used as an electrolyte / separator without using a separator. Except for the above, a coin-shaped battery was produced in the same manner as in Example 1.
【００４７】ポリマー電解質の膜は以下のようにして作
製した。まず、アクリロニトリル−酢酸ビニル共重合体
（重量比：９３：７）、ＬｉＰＦ6 、エチレンカーボネ
イト、およびプロピレンカーボネイトを重量比で５：１
０：５５：３０で混合し、この混合液を１４０℃で数分
間加熱しガラス板上にキャストした。これを、上からガ
ラス板で挟み、２０℃で一昼夜放置し、厚さ２５μｍの
ゲル状の膜を作製した。この膜を所定寸法の円形に打ち
抜いて電解質兼セパレータを作製し、これを正極と負極
の間に挿入した。The polymer electrolyte membrane was prepared as follows. First, an acrylonitrile-vinyl acetate copolymer (weight ratio: 93: 7), LiPF 6 , ethylene carbonate, and propylene carbonate were mixed at a weight ratio of 5: 1.
The mixture was mixed at 0:55:30, and the mixture was heated at 140 ° C. for several minutes and cast on a glass plate. This was sandwiched between glass plates from above, and allowed to stand at 20 ° C. for 24 hours to form a gel-like film having a thickness of 25 μm. This membrane was punched out into a circle having a predetermined size to produce an electrolyte / separator, which was inserted between the positive electrode and the negative electrode.
【００４８】架橋ポリアニリンは、１ｍｏｌ／ｌのアニ
リンの塩酸水溶液中で、銀／塩化銀参照極に対して１Ｖ
の定電位を白金板に印加して酸化重合を行い、白金板上
の重合物を水とアルコールで洗浄し、乾燥後に粉砕して
作製した。この電解重合法による架橋ポリアニリンをメ
タノールに溶解し、ヒドラジンを少量ずつ添加すること
で得られた還元脱ドープ状態のポリアニリンを使用し
た。The crosslinked polyaniline is prepared by adding 1 V to a silver / silver chloride reference electrode in an aqueous solution of 1 mol / l aniline in hydrochloric acid.
Was applied to a platinum plate to carry out oxidative polymerization, and the polymer on the platinum plate was washed with water and alcohol, dried, and then pulverized to produce a polymer. The crosslinked polyaniline obtained by the electrolytic polymerization method was dissolved in methanol, and hydrazine was added little by little to obtain a polyaniline in a reduced undoped state.
【００４９】《実施例９》正極ペースト中の配合比を、
重量比で高分子量無定形硫黄：ポリアニリン：銀微粒子
＝６６：３３：１とした以外は、実施例６と同様にして
コイン形電池を作製した。Example 9 The mixing ratio in the positive electrode paste was
A coin-shaped battery was produced in the same manner as in Example 6, except that the weight ratio of high molecular weight amorphous sulfur: polyaniline: silver fine particles was 66: 33: 1.
【００５０】《実施例１０》正極ペースト中の配合比
を、重量比で高分子量無定形硫黄：ポリアニリン：銅微
粒子＝４５：５０：５とした以外は、実施例６と同様に
してコイン形電池を作製した。Example 10 A coin-type battery was manufactured in the same manner as in Example 6, except that the compounding ratio in the positive electrode paste was 45: 50: 5 by weight ratio of high molecular weight amorphous sulfur: polyaniline: copper fine particles. Was prepared.
【００５１】《実施例１１》正極ペースト中の配合比
を、重量比で高分子量無定形硫黄：ポリアニリン：銅微
粒子＝５５：２５：２０とした以外は、実施例６と同様
にしてコイン形電池を作製した。Example 11 A coin-type battery was manufactured in the same manner as in Example 6, except that the compounding ratio in the positive electrode paste was changed to high molecular weight amorphous sulfur: polyaniline: copper fine particles = 55: 25: 20 by weight ratio. Was prepared.
【００５２】《実施例１２》正極ペースト中の配合比
を、重量比で高分子量無定形硫黄：ポリアニリン：銅微
粒子＝８０：１５：５とした以外は、実施例６と同様に
してコイン形電池を作製した。Example 12 A coin-type battery was prepared in the same manner as in Example 6, except that the compounding ratio in the positive electrode paste was changed to high molecular weight amorphous sulfur: polyaniline: copper fine particles = 80: 15: 5 by weight ratio. Was prepared.
【００５３】《比較例１》高分子量無定形硫黄の代わり
に、正極に結晶性硫黄（細井化学製、沈降硫黄）を含有
させた以外は、実施例１と同様にしてコイン形電池を作
製した。Comparative Example 1 A coin-type battery was produced in the same manner as in Example 1 except that the positive electrode contained crystalline sulfur (produced by Hosoi Chemical Co., Ltd., precipitated sulfur) instead of the high molecular weight amorphous sulfur. .
【００５４】《比較例２》数平均分子量８００の高分子
量無定形硫黄の代わりに、液相から急冷して得られた数
平均分子量２５０、二硫化炭素への２５℃における溶解
度２．５ｇ／１００ｃｃの無定形硫黄を用いた以外は、
実施例４と同様にしてコイン形電池を作製した。Comparative Example 2 Instead of high molecular weight amorphous sulfur having a number average molecular weight of 800, a number average molecular weight of 250 obtained by quenching from a liquid phase, solubility in carbon disulfide at 25 ° C. of 2.5 g / 100 cc Except that amorphous sulfur was used.
A coin-shaped battery was produced in the same manner as in Example 4.
【００５５】《比較例３》正極にポリアニリンを混合せ
ず、その代わりに同じ重量比でポリフッ化ビニリデンを
混合した以外は、実施例１と同様にして、コイン形電池
を作製した。Comparative Example 3 A coin-type battery was produced in the same manner as in Example 1, except that polyaniline was not mixed in the positive electrode, and instead polyvinylidene fluoride was mixed in the same weight ratio.
【００５６】実施例１〜１２と比較例１〜３のそれぞれ
の電池について、温度２０℃、充電終止電圧４．２Ｖ、
放電終止電圧２Ｖ、充放電電流密度０．３ｍＡ／ｃｍ2
の条件で充放電サイクル試験を行った。初回の放電容量
の６０％の放電容量が維持された充放電サイクル数をサ
イクル寿命とした。また、初回の放電における放電持続
時間の５０％の時点での電池電圧を平均放電電圧とし
た。For each of the batteries of Examples 1 to 12 and Comparative Examples 1 to 3, the temperature was 20 ° C., the charging end voltage was 4.2 V,
Discharge end voltage 2 V, charge / discharge current density 0.3 mA / cm 2
A charge / discharge cycle test was performed under the following conditions. The cycle life was defined as the number of charge / discharge cycles at which 60% of the initial discharge capacity was maintained. The battery voltage at the time of 50% of the discharge duration time in the first discharge was defined as the average discharge voltage.
【００５７】前記充放電サイクル試験とは別に、各実施
例および各比較例のそれぞれの電池について、前記と同
様の条件で１０サイクルの充放電試験を行った後、放電
状態で６０℃の雰囲気中に１０日間保存した。保存後の
電池について、同様の条件で充放電を続けた。６０℃保
存前（１０サイクル目）の放電容量に対する保存後の初
回充電後の放電容量の比率（％）を、保存後回復率とし
た。Separately from the charge / discharge cycle test, each of the batteries of Examples and Comparative Examples was subjected to a 10-cycle charge / discharge test under the same conditions as described above, and then discharged in a 60 ° C. atmosphere. For 10 days. The battery after storage was continuously charged and discharged under the same conditions. The ratio (%) of the discharge capacity after the initial charge after storage to the discharge capacity before storage at 60 ° C. (10th cycle) was defined as the post-storage recovery rate.
【００５８】代表的な電池の初回の放電曲線を図２に示
す。図２に見られるように、導電性高分子と高分子量無
定形硫黄を組み合わた正極活物質を用いた実施例１で
は、４〜３Ｖの高放電電圧領域で大きな放電容量が得ら
れた。一方、実施例１の高分子量無定形硫黄の代わりに
結晶性硫黄を用いた比較例１の場合は、放電当初の４〜
３Ｖから急速に２Ｖまで放電電圧が低下する二段の放電
曲線を示した。FIG. 2 shows the initial discharge curve of a typical battery. As shown in FIG. 2, in Example 1 using the positive electrode active material in which the conductive polymer and the high molecular weight amorphous sulfur were combined, a large discharge capacity was obtained in a high discharge voltage region of 4 to 3 V. On the other hand, in the case of Comparative Example 1 in which crystalline sulfur was used instead of the high molecular weight amorphous sulfur in Example 1, 4 to 4 at the beginning of discharge was used.
The graph shows a two-stage discharge curve in which the discharge voltage rapidly decreases from 3V to 2V.
【００５９】負極にＬｉ2.6Ｃｏ0.4Ｎを用いた実施例５
では、金属リチウムを用いた実施例１よりも若干低いが
３Ｖ級の安定した放電電圧を示し、大きな放電容量が得
られた。また、正極活物質として導電性高分子を用いず
に、高分子量無定形硫黄を単独で用いた比較例３では、
放電容量は大きいが、放電電圧は約２Ｖという低電圧で
あった。上記実施例１および６以外の各実施例の電池の
場合にも、実施例１とほぼ同等の４〜３Ｖの高電圧領域
での安定した放電曲線が得られた。但し、正極集電体に
カーボン表面層を施していない実施例７では、他の実施
例よりも若干小さな放電容量を示した。Example 5 using Li 2.6 Co 0.4 N for the negative electrode
Showed a stable discharge voltage of 3V class, though slightly lower than that of Example 1 using metallic lithium, and a large discharge capacity was obtained. In Comparative Example 3 in which high-molecular-weight amorphous sulfur was used alone without using a conductive polymer as the positive electrode active material,
Although the discharge capacity was large, the discharge voltage was as low as about 2V. Also in the case of the batteries of the examples other than the examples 1 and 6, a stable discharge curve in a high voltage region of 4 to 3 V almost equivalent to that of the example 1 was obtained. However, in Example 7 in which the carbon surface layer was not applied to the positive electrode current collector, the discharge capacity was slightly smaller than in the other examples.
【００６０】表１には、各実施例および各比較例の全て
の電池についての放電平均電圧、保存後回復率、および
サイクル寿命を示す。Table 1 shows the average discharge voltage, the recovery rate after storage, and the cycle life of all the batteries of each of the examples and comparative examples.
【００６１】[0061]
【表１】 [Table 1]
【００６２】実施例ではいずれも保存後回復率が約８０
％以上、サイクル寿命が２３０〜４６０サイクルである
のに対して、比較例ではいずれも保存後回復率が４０〜
６０％、サイクル寿命が８０サイクル以下であった。実
施例１、２および３の比較、ならびに実施例４と比較例
２の比較から、鎖状ポリアニリンと組み合わせて正極活
物質に用いる無定形硫黄の分子量および、二硫化炭素へ
の溶解度が電池特性に大きく影響することが確認され
た。In each of the examples, the recovery rate after storage was about 80.
% Or more, and the cycle life is 230 to 460 cycles, whereas the recovery rate after storage is 40 to 40 in all the comparative examples.
60%, and the cycle life was 80 cycles or less. From the comparison between Examples 1, 2 and 3, and from the comparison between Example 4 and Comparative Example 2, the molecular weight and the solubility of amorphous sulfur used in the positive electrode active material in combination with the linear polyaniline in the carbon disulfide to the battery characteristics are improved. It was confirmed that it had a significant effect.
【００６３】すなわち、数平均分子量が大きくなるほ
ど、あるいは二硫化炭素への溶解度が小さくなるほど、
平均放電電圧、保存後回復率、およびサイクル寿命の各
特性とも優れた値を示した。数平均分子量が３００〜８
００で、二硫化炭素への溶解度が１〜２ｇ／１００ｃｃ
の高分子量無定形硫黄を用いた実施例１〜３では、数平
均分子量が２５０で、二硫化炭素への溶解度が２．５ｇ
／１００ｃｃの無定形硫黄を用いた比較例２よりも、各
特性において著しく優れた性能値が得られた。That is, as the number average molecular weight increases or the solubility in carbon disulfide decreases,
The average discharge voltage, the recovery rate after storage, and the cycle life exhibited excellent values. Number average molecular weight of 300 to 8
00, the solubility in carbon disulfide is 1-2 g / 100 cc
In Examples 1 to 3 using high-molecular-weight amorphous sulfur, the number average molecular weight was 250 and the solubility in carbon disulfide was 2.5 g.
In comparison with Comparative Example 2 using / 100 cc of amorphous sulfur, remarkably excellent performance values were obtained in each characteristic.
【００６４】鎖状ポリアニリンと組み合わせて結晶性硫
黄を正極活物質に用いた比較例１、および数平均分子量
８００の高分子量無定形硫黄を単独で正極活物質に用い
た比較例３は、各電池特性において、比較例２よりさら
に一段と低い値を示した。ポリエステル系ポリマー電解
質を用いた実施例４および５は、液状の有機電解質を用
いた他の実施例と比較しても一段と優れた保存後回復率
およびサイクル寿命を示した。また、導電性高分子とし
て鎖状ポリアニリンを用いた実施例４および５は、架橋
ポリアニリンとポリアクリロニトリル系ポリマー電解質
を用いた実施例８よりも、保存回復率、サイクル寿命と
もに優れた特性が得られた。さらに、実施例１と実施例
７の比較から、正極集電体に設けたカーボン表面層が各
電池特性を高める効果が非常に大きいことが確認され
た。In Comparative Example 1 in which crystalline sulfur was used as the positive electrode active material in combination with chain polyaniline, and in Comparative Example 3 in which high molecular weight amorphous sulfur having a number average molecular weight of 800 was used alone as the positive electrode active material, In the characteristics, the value was much lower than that of Comparative Example 2. Examples 4 and 5 using the polyester-based polymer electrolyte exhibited even more excellent recovery rates after storage and cycle life than the other examples using the liquid organic electrolyte. Further, in Examples 4 and 5 using the chain polyaniline as the conductive polymer, characteristics excellent in both the storage recovery rate and the cycle life were obtained compared to Example 8 using the crosslinked polyaniline and the polyacrylonitrile-based polymer electrolyte. Was. Furthermore, from a comparison between Example 1 and Example 7, it was confirmed that the carbon surface layer provided on the positive electrode current collector had an extremely large effect of improving each battery characteristic.
【００６５】[0065]
【発明の効果】本発明による高分子量無定形硫黄と導電
性高分子の複合正極の作用により、正極の放電生成物の
電解質への溶解を抑制し、正極電位を高めることができ
る。この正極を用いて、高電圧で充放電サイクル特性お
よび保存特性に優れた高容量リチウム二次電池を提供す
ることができる。The effect of the composite positive electrode of high molecular weight amorphous sulfur and conductive polymer according to the present invention can suppress the dissolution of the discharge product of the positive electrode into the electrolyte and increase the positive electrode potential. By using this positive electrode, a high-capacity lithium secondary battery having excellent charge / discharge cycle characteristics and storage characteristics at a high voltage can be provided.
【図１】本発明の実施例におけるリチウム二次電池の縦
断面図である。FIG. 1 is a longitudinal sectional view of a lithium secondary battery according to an embodiment of the present invention.
【図２】本発明の実施例と比較例のリチウム二次電池の
放電特性を示す図である。FIG. 2 is a diagram showing discharge characteristics of lithium secondary batteries of an example of the present invention and a comparative example.
１ 電池ケース ２ 正極集電体 ３ カーボン表面層 ４ 正極 ５ セパレータ ６ 負極 ７ 封口板 ８ ガスケット DESCRIPTION OF SYMBOLS 1 Battery case 2 Positive electrode collector 3 Carbon surface layer 4 Positive electrode 5 Separator 6 Negative electrode 7 Sealing plate 8 Gasket
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.7 識別記号 ＦＩ テーマコート゛(参考） Ｈ０１Ｍ 4/02 Ｈ０１Ｍ 4/02 Ｄ 4/58 4/58 4/62 4/62 Ｚ 4/66 4/66 Ａ 10/40 10/40 Ｂ Ｚ (72)発明者 武澤 秀治 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 稲富 友 大阪府門真市大字門真1006番地 松下電器 産業株式会社内 Ｆターム(参考） 4J002 BM001 CE001 CM011 CN011 DA017 DA046 DA077 DA087 DA107 FD117 GQ00 5H017 AA03 AS10 BB08 CC01 DD05 EE04 EE05 EE06 EE09 EE10 HH00 HH01 HH08 5H029 AJ03 AJ04 AJ05 AK16 AK18 AL02 AL03 AL06 AL11 AL12 AL18 AM03 AM07 AM16 BJ03 BJ13 CJ02 CJ08 CJ22 CJ28 DJ07 DJ08 DJ16 DJ17 DJ18 EJ01 EJ04 HJ00 HJ01 HJ02 HJ11 HJ13 HJ14 5H050 AA07 AA08 AA09 BA15 CA20 CA26 CA29 CB02 CB03 CB07 CB11 CB12 CB29 DA02 DA04 DA06 DA08 DA10 DA13 EA02 EA03 EA04 EA08 FA17 FA18 FA19 FA20 GA02 GA10 GA22 GA27 HA00 HA01 HA02 HA11 HA13 HA14 ──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. 7 Identification symbol FI Theme coat ゛ (Reference) H01M 4/02 H01M 4/02 D 4/58 4/58 4/62 4/62 Z 4/66 4 / 66 A 10/40 10/40 BZ (72) Inventor Hideharu Takezawa 1006 Odaka, Kazuma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. In-house F-term (reference) 4J002 BM001 CE001 CM011 CN011 DA017 DA046 DA077 DA087 DA107 FD117 GQ00 5H017 AA03 AS10 BB08 CC01 DD05 EE04 EE05 EE06 EE09 EE10 HH00 HH01 HH08 5H029 AJ03 AJ04 AJ05 AL16 AM03 AL16 AM03 CJ02 CJ08 CJ22 CJ28 DJ07 DJ08 DJ16 DJ17 DJ18 EJ01 EJ04 HJ00 HJ01 HJ02 HJ11 HJ13 HJ14 5H050 AA07 AA08 AA09 BA15 CA20 CA26 CA29 CB02 CB03 CB07 CB11 CB12 CB29 DA02 DA04 DA06 DA08 DA10 DA13 EA EA03 EA04 EA08 FA17 FA18 FA19 FA20 GA02 GA10 GA22 GA27 HA00 HA01 HA02 HA11 HA13 HA14
Claims (14)
よび導電性高分子を含む正極、負極、および非水電解質
を備えたことを特徴とするリチウム二次電池。1. A lithium secondary battery comprising a positive electrode containing amorphous sulfur having a number average molecular weight of 300 or more and a conductive polymer, a negative electrode, and a non-aqueous electrolyte.
５℃での溶解度が、２ｇ／１００ｃｃ以下である請求項
１に記載のリチウム二次電池。2. The method according to claim 2, wherein said amorphous sulfur is carbon
The lithium secondary battery according to claim 1, having a solubility at 5 ° C of 2 g / 100 cc or less.
加熱して気化させた硫黄を、５０℃以下に急冷して作製
されたものである請求項１または２に記載のリチウム二
次電池。3. The lithium secondary battery according to claim 1, wherein the amorphous sulfur is produced by rapidly cooling sulfur vaporized by heating to 450 to 700 ° C. to 50 ° C. or less. .
請求項１〜３のいずれかに記載のリチウム二次電池。4. The lithium secondary battery according to claim 1, wherein the conductive polymer has a chain structure.
ポリアセン、ポリアニリン、ポリピロール、ポリチオフ
ェン、ポリ−ｐ−フェニレンスルフィド、およびポリピ
リジノピリジンよりなる群から選ばれた少なくとも１種
類である請求項１〜４のいずれかに記載のリチウム二次
電池。5. The method according to claim 1, wherein the conductive polymer is polyacetylene,
The lithium secondary battery according to any one of claims 1 to 4, wherein the lithium secondary battery is at least one selected from the group consisting of polyacene, polyaniline, polypyrrole, polythiophene, poly-p-phenylene sulfide, and polypyridinopyridine.
高分子の重量比が、８０〜５０：５０〜２０である請求
項１〜５のいずれかに記載のリチウム二次電池。6. The lithium secondary battery according to claim 1, wherein the weight ratio of amorphous sulfur to the conductive polymer contained in the positive electrode is 80 to 50:50 to 20.
項１〜６のいずれかに記載のリチウム二次電池。7. The lithium secondary battery according to claim 1, wherein the positive electrode further contains a conductive auxiliary.
ルト、鉄、亜鉛、錫、および炭素よりなる群から選ばれ
た少なくとも１種類からなる粉末である請求項７に記載
のリチウム二次電池。8. The lithium secondary battery according to claim 7, wherein the conductive assistant is a powder of at least one selected from the group consisting of copper, silver, nickel, cobalt, iron, zinc, tin, and carbon. battery.
高分子、および導電助剤の重量比が、８０〜３０：５０
〜１０：２０〜１である請求項７または８に記載のリチ
ウム二次電池。9. The weight ratio of amorphous sulfur, conductive polymer, and conductive auxiliary contained in the positive electrode is 80 to 30:50.
The lithium secondary battery according to claim 7, wherein the ratio is from 10 to 20: 1.
が、アルミニウム、チタン、およびステンレス鋼よりな
る群から選ばれた少なくとも１種類からなり、その表面
に炭素を含む層を有する請求項１〜９のいずれかに記載
のリチウム二次電池。10. The positive electrode has a current collector, and the current collector is made of at least one selected from the group consisting of aluminum, titanium, and stainless steel, and has a layer containing carbon on its surface. Item 10. The lithium secondary battery according to any one of Items 1 to 9.
ル骨格、エーテル骨格、およびアクリロニトリルのいず
れかを有するポリマーを含む固体状またはゲル状のポリ
マー電解質である請求項１〜１０のいずれかに記載のリ
チウム二次電池。11. The solid or gel-like polymer electrolyte containing a polymer having any of an ester skeleton, an ether skeleton, and acrylonitrile as a main chain of the non-aqueous electrolyte. Lithium secondary battery.
ステル骨格を有し、側鎖として１級アルキルアミノ基を
有するアクリレートポリマーまたはメタクリレートポリ
マーを含む請求項１１に記載のリチウム二次電池。12. The lithium secondary battery according to claim 11, wherein the polymer electrolyte includes an acrylate polymer or a methacrylate polymer having an ester skeleton as a main chain and a primary alkylamino group as a side chain.
ＣｏxＮ（０＜ｘ＜１）で表される化合物である請求項
１〜１２のいずれかに記載のリチウム二次電池。13. The main material of the negative electrode has a general formula Li 3-x
The lithium secondary battery according to claim 1, which is a compound represented by Co x N (0 <x <1).
工程、前記導電性高分子の有機溶媒溶液に数平均分子量
３００以上の無定形硫黄粉末を分散させる工程、前記無
定形硫黄粉末を分散させた液に導電助剤を分散させて正
極ペーストを作製する工程、前記正極ペーストを正極集
電体に塗布する工程、および前記正極ペーストを塗布し
た正極集電体を乾燥して正極板を作製する工程を有する
ことを特徴とするリチウム二次電池の製造方法。14. A step of dissolving a conductive polymer in an organic solvent, a step of dispersing amorphous sulfur powder having a number average molecular weight of 300 or more in an organic solvent solution of the conductive polymer, and dispersing the amorphous sulfur powder. Preparing a positive electrode paste by dispersing a conductive additive in the liquid, a step of applying the positive electrode paste to a positive electrode current collector, and drying the positive electrode current collector coated with the positive electrode paste to prepare a positive electrode plate A method for producing a lithium secondary battery, comprising the steps of:
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|---|---|---|---|
| JP2001134367A JP2002329495A (en) | 2001-05-01 | 2001-05-01 | Lithium secondary battery and production process thereof |
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