JPH09129237A - Electrode for battery and manufacture thereof - Google Patents

Electrode for battery and manufacture thereof

Info

Publication number
JPH09129237A
JPH09129237A JP7285924A JP28592495A JPH09129237A JP H09129237 A JPH09129237 A JP H09129237A JP 7285924 A JP7285924 A JP 7285924A JP 28592495 A JP28592495 A JP 28592495A JP H09129237 A JPH09129237 A JP H09129237A
Authority
JP
Japan
Prior art keywords
binder
carboxylic acid
electrode
group
peroxide
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
Application number
JP7285924A
Other languages
Japanese (ja)
Inventor
Yoshiyuki Miyaki
義行 宮木
Kazuyoshi Ohashi
和義 大橋
Akisue Yonekura
明季 米倉
Kuniyuki Goto
邦之 後藤
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Arkema KK
Original Assignee
Elf Atochem Japan KK
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Elf Atochem Japan KK filed Critical Elf Atochem Japan KK
Priority to JP7285924A priority Critical patent/JPH09129237A/en
Publication of JPH09129237A publication Critical patent/JPH09129237A/en
Pending legal-status Critical Current

Links

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

PROBLEM TO BE SOLVED: To provide an electrode for a battery in which the adhesion of an electrode active material with a current collector is increased and cycle characteristics are improved by using a binder into which a carboxylic acid group or a carboxylic anhydride group is introduced by heat treating the binder under the existence of a peroxide having at least one of these groups. SOLUTION: A carboxylic acid group or a carboxylic anhydride group is introduced into a binder by heat treating the binder under the existence of an organic peroxide having at least one functional group selected from the carboxylic acid group and the carboxylic anhydride group, or under the existence of an unsaturated organic compound and a peroxide having at least one functional group selected from the carboxylic acid group and the carboxylic anhydride group. The binder obtained is used in an electrode for a battery.

Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【産業上の利用分野】本発明は、改良された電池用電極
およびその作製方法に関する。FIELD OF THE INVENTION The present invention relates to an improved battery electrode and a method for producing the same.

【０００２】[0002]

【従来の技術】近年、携帯電話、ビデオカメラ、ノート
型パソコン等のポータブル機器の普及に伴い、小型で高
容量、長寿命の二次電池に対する需要が高まっている。
特に、現在、注目されている二次電池として、リチウム
二次電池がある。2. Description of the Related Art In recent years, with the widespread use of portable devices such as mobile phones, video cameras, and notebook computers, there has been an increasing demand for compact, high-capacity, long-life secondary batteries.
In particular, a lithium secondary battery is currently receiving attention as a secondary battery.

【０００３】リチウム二次電池の負極活性物質として
は、リチウムイオンをドーピング、脱ドーピングするコ
ークスやグラファイト等の炭素質材料を用いることが提
案されているが（特開昭６２−９０８６３号公報）、こ
の場合、通常、粉体状の炭素材料に結着剤を適当量添加
した混合物に溶媒を混ぜてペースト状にしたものを集電
体に塗布、乾燥後圧着させて電極が得られる。As a negative electrode active material for a lithium secondary battery, it has been proposed to use a carbonaceous material such as coke or graphite for doping and dedoping lithium ions (Japanese Patent Laid-Open No. 62-90863). In this case, usually, a mixture of a powdery carbon material and an appropriate amount of a binder is mixed with a solvent to form a paste, which is applied to a current collector, dried and then pressure-bonded to obtain an electrode.

【０００４】また、リチウム二次電池の正極活性物質と
しては、マンガン酸化物、五酸化バナジウムのような遷
移金属酸化物、硫化鉄、硫化チタンのような遷移金属酸
化物、さらにこれらとリチウムとの複合化合物（例え
ば、リチウムコバルト複合酸化物、リチウムコバルトニ
ッケル複合酸化物、リチウムマンガン酸化物）などが提
案されている。これらの材料を正極に組み込む場合も、
粉体状の正極活性物質に導電体（カーボンを用いること
が多い）と結着剤を適量添加した混合物に溶媒を混ぜて
ペースト状にしたものを集電体に塗布、乾燥後圧着させ
て電極が得られる。Further, as a positive electrode active material of a lithium secondary battery, manganese oxide, transition metal oxides such as vanadium pentoxide, transition metal oxides such as iron sulfide and titanium sulfide, and further, these and lithium are used. Composite compounds (for example, lithium cobalt composite oxide, lithium cobalt nickel composite oxide, lithium manganese oxide) and the like have been proposed. When incorporating these materials into the positive electrode,
A mixture of a powdered positive electrode active material with an appropriate amount of a conductor (carbon is often used) and a binder is mixed with a solvent to form a paste, which is applied to a current collector, dried, and then pressure-bonded to form an electrode. Is obtained.

【０００５】このような二次電池の電極に用いる結着剤
には、強い耐溶剤性と耐薬品性が要求されるため、多く
の場合、フッ素系の樹脂が用いられる。しかしながら、
フッ素系の樹脂は元来金属との接着性が悪く、負極と正
極いずれの場合も、活性物質を集電体に圧着させた後、
集電体と活性物質との接着力が十分でないために、活性
物質が集電体から剥離し易く、電池のサイクル特性が悪
くなるという問題があった。これを改善する方法とし
て、集電体表面を粗面化することが提案されたが（特開
平５−６７６６）、これにおいても接着性は十分とは言
えず、さらなる改良が求められている。Since a strong solvent resistance and chemical resistance are required for the binder used for the electrode of such a secondary battery, a fluorine resin is often used. However,
Fluorine-based resin originally has poor adhesion to metal, and in both cases of negative electrode and positive electrode, after pressing the active substance onto the current collector,
Since the adhesive force between the current collector and the active substance is not sufficient, there is a problem that the active substance is easily peeled from the current collector and the cycle characteristics of the battery are deteriorated. As a method of improving this, it has been proposed to roughen the surface of the current collector (JP-A-5-6766), but even in this case, the adhesiveness is not sufficient and further improvement is required.

【０００６】また、フッ化ビニリデンとカルボン酸基を
有するモノマーとの共重合体（特開平６−１７２４５
２）が提案されたが、通常、フッ素系モノマーとカルボ
ン酸基を有する他のモノマーとの共重合は容易でなく、
量産化が困難で実用的とは言えない．Further, a copolymer of vinylidene fluoride and a monomer having a carboxylic acid group (JP-A-6-17245).
2) has been proposed, but usually, it is not easy to copolymerize a fluorine-based monomer with another monomer having a carboxylic acid group,
Mass production is difficult and not practical.

【０００７】[0007]

【発明が解決しようとする課題】本発明は、簡便な方法
で電極活性物質と集電体との接着性を向上させ、サイク
ル特性が改善された電池用電極を得ることを目的とす
る。SUMMARY OF THE INVENTION It is an object of the present invention to obtain a battery electrode having improved cycle characteristics by improving the adhesion between the electrode active substance and the current collector by a simple method.

【０００８】[0008]

【課題を解決するための手段】本発明者らは、集電体の
表面に少なくとも電極活性物質と結着剤からなる電極構
成物質層が形成されている電池用電極において、過酸化
物を利用することにより結着剤にカルボン酸基あるいは
カルボン酸無水物基が容易に導入され、これにより電極
活性物質と集電体との接着強度を改善させ得ることを見
いだし本発明に到達した。DISCLOSURE OF THE INVENTION The present inventors have utilized a peroxide in a battery electrode in which an electrode-constituting substance layer composed of at least an electrode active substance and a binder is formed on the surface of a current collector. By doing so, it was found that a carboxylic acid group or a carboxylic acid anhydride group was easily introduced into the binder, and thereby the adhesive strength between the electrode active substance and the current collector could be improved, and the present invention was reached.

【０００９】すなわち、本発明は、集電体の表面に少な
くとも電極活性物質と結着剤からなる電極構成物質層が
形成されている電池用電極において、結着剤にカルボン
酸基あるいはカルボン酸無水物基が、（ａ）カルボン酸
基とカルボン酸無水物基から選ばれる少なくとも１つの
官能基を有する有機過酸化物の存在下で結着剤を加熱処
理する方法、あるいは（ｂ）カルボン酸基とカルボン酸
無水物基から選ばれる少なくとも１つの官能基を有する
不飽和有機化合物と過酸化物の存在下で結着剤を加熱処
理する方法のいずれかの方法により導入されていること
を特徴とする電池用電極に関する。That is, according to the present invention, in a battery electrode in which an electrode constituent substance layer comprising at least an electrode active substance and a binder is formed on the surface of a current collector, a carboxylic acid group or a carboxylic anhydride is added to the binder. Physical group is (a) a method of heat treating a binder in the presence of an organic peroxide having at least one functional group selected from a carboxylic acid group and a carboxylic acid anhydride group, or (b) a carboxylic acid group And an unsaturated organic compound having at least one functional group selected from a carboxylic acid anhydride group and a method of heat treating the binder in the presence of a peroxide. The present invention relates to a battery electrode.

【００１０】電極の集電体としては、金属箔、金属メッ
シュ、三次元多孔体等があるが、この集電体に用いる金
属としては、リチウムと合金ができ難い金属が望まし
く、特に、鉄、ニッケル、コバルト、銅、アルミニウ
ム、チタン、バナジウム、クロム、マンガンが単独、あ
るいはこれらの合金で用いられる。The electrode current collector may be a metal foil, a metal mesh, a three-dimensional porous body, or the like. The metal used for this current collector is preferably a metal that is difficult to alloy with lithium, and particularly iron, Nickel, cobalt, copper, aluminum, titanium, vanadium, chromium and manganese are used alone or in alloys thereof.

【００１１】電極活性物質のうち負極活性物質として
は、リチウムイオンをドーピング、脱ドーピングし得る
材料であればよい。このような材料として、石油系コー
クスや炭素系コークスなどのコークス材料、アセチレン
ブラックなどのカーボンブラック類、グラファイト、ガ
ラス状炭素、活性炭、炭素繊維、有機高分子を非酸化性
雰囲気中で焼成して得られる有機高分子焼成体等の炭素
質材料がある。また、酸化銅を添加する場合もある。The negative electrode active material among the electrode active materials may be any material capable of doping and dedoping lithium ions. As such materials, coke materials such as petroleum coke and carbon coke, carbon blacks such as acetylene black, graphite, glassy carbon, activated carbon, carbon fiber, and organic polymers are fired in a non-oxidizing atmosphere. There is a carbonaceous material such as a fired organic polymer obtained. In some cases, copper oxide is added.

【００１２】また、正極活性物質としては、上述の一般
に使用されるものであり、特に限定されない。さらに、
これに導電体を添加してもよい。Further, the positive electrode active material is one that is generally used and is not particularly limited. further,
A conductor may be added to this.

【００１３】通常、結着剤として用いられる樹脂には、
フッ素系樹脂、ポリオレフィン系樹脂、合成ゴム等があ
る。これらのうちフッ素系樹脂が好ましく用いられる
が、このようなフッ素系樹脂の例としては、四フッ化エ
チレン、三フッ化エチレン、三フッ化塩化エチレン、フ
ッ化ビニリデン、フッ化ビニル、六フッ化プロピレン、
パ−フルオロアルキルビニルエ−テル類から選ばれた少
なくとも一種のモノマーを構成単位として含み、樹脂全
体に対するこれらモノマーの比率の和が５０重量％以
上、さらに好ましくは７０重量％以上である熱可塑性フ
ッ素樹脂が挙げられる。これらのフッ素系樹脂は、結着
剤に９０重量％以上含まれることが望ましい。このよう
な結着剤は、を耐溶剤性と耐薬品性に優れているため、
電極活性物質の結着剤として用いれば、高性能で安定な
電極が得られる。Usually, the resin used as the binder is
Fluorine-based resin, polyolefin-based resin, synthetic rubber and the like are available. Of these, fluororesins are preferably used, and examples of such fluororesins include tetrafluoroethylene, trifluoroethylene, trifluoroethylene chloride, vinylidene fluoride, vinyl fluoride, and hexafluoride. propylene,
Thermoplastic fluorine containing at least one monomer selected from perfluoroalkyl vinyl ethers as a constitutional unit, and the sum of the ratio of these monomers to the whole resin is 50% by weight or more, more preferably 70% by weight or more. Resins may be mentioned. It is desirable that the binder contains 90% by weight or more of these fluororesins. Since such a binder has excellent solvent resistance and chemical resistance,
When used as a binder for an electrode active substance, a high-performance and stable electrode can be obtained.

【００１４】フッ素系樹脂の具体例として、ポリテトラ
フルオロエチレン、ポリフッ化ビニル、ポリ三フッ化エ
チレン、ポリ三フッ化塩化エチレン、フッ化ビニリデン
・三フッ化塩化エチレン共重合体、エチレン・四フッ化
エチレン共重合体、四フッ化エチレン・六フッ化プロピ
レン共重合体、ＰＶＤＦ系樹脂等がある。これらのう
ち、ＰＶＤＦ系樹脂は、電池に用いられる溶剤や発生す
る活性種に対する耐久性を有し、且つ電極の作製時に用
いられるＮ−メチルピロリドン等への溶解性が良好であ
るため、特に好んで用いられる。Specific examples of the fluorine resin include polytetrafluoroethylene, polyvinyl fluoride, polytrifluoroethylene, polytrifluoroethylene chloride, vinylidene fluoride / trifluoroethylene chloride copolymer, and ethylene / tetrafluoroethylene. Ethylene copolymer, tetrafluoroethylene / hexafluoropropylene copolymer, PVDF resin and the like. Of these, PVDF-based resins are particularly preferable because they have durability against solvents used in batteries and active species generated, and have good solubility in N-methylpyrrolidone and the like used during the production of electrodes. Used in

【００１５】ここでいうＰＶＤＦ系樹脂とは、ポリフツ
化ビニリデンホモポリマーに限定されずフツ化ビニリデ
ンと共重合可能な他のモノマーとの共重合体も含み、共
重合体中のフッ化ビニリデン成分が５０重量％以上であ
ればよく、望ましくは８０重量％以上、さらに望ましく
は９０重量％以上である。共重合可能な他のモノマーと
しては、四フッ化エチレン、六フッ化プロピレン、三フ
ッ化エチレン、三フッ化塩化エチレン、フッ化ビニル等
のフッ素系モノマーが挙げられ、これらの１種又は２種
以上を用いることが出来る。The PVDF-based resin as used herein is not limited to polyvinylidene fluoride homopolymer, but includes a copolymer of vinylidene fluoride and another monomer copolymerizable with the vinylidene fluoride component. It may be 50% by weight or more, preferably 80% by weight or more, and more preferably 90% by weight or more. Other copolymerizable monomers include fluorine-based monomers such as ethylene tetrafluoride, propylene hexafluoride, ethylene trifluoride, ethylene trifluoride chloride, and vinyl fluoride, and one or two of these monomers may be used. The above can be used.

【００１６】本発明で用いる（ａ）の方法においては、
結着剤として用いる樹脂を、カルボン酸基とカルボン酸
無水物基から選ばれる少なくとも１つの官能基を有する
有機過酸化物の存在下で加熱処理することにより当該樹
脂にカルボン酸基あるいはカルボン酸無水物基が導入さ
れる。In the method (a) used in the present invention,
The resin used as the binder is heat-treated in the presence of an organic peroxide having at least one functional group selected from a carboxylic acid group and a carboxylic acid anhydride group to give the resin a carboxylic acid group or a carboxylic acid anhydride. A physical group is introduced.

【００１７】また、ここで用いられるカルボン酸基とカ
ルボン酸無水物基から選ばれる少なくとも１つの官能基
を有する過酸化物過酸化物の例として、ジコハク酸パー
オキサイド、ｔ−ブチルパーオキシマレイン酸等があ
る。過酸化物存在下での結着剤樹脂の加熱処理は、溶液
中あるいは溶媒への分散液中で、過酸化物の１０時間半
減期温度以上の温度で、１分間〜１０時間行うことが望
ましく、さらに望ましくは１０分間〜５時間である。Further, examples of the peroxide peroxide having at least one functional group selected from the carboxylic acid group and the carboxylic acid anhydride group used here include disuccinic acid peroxide and t-butylperoxymaleic acid. Etc. The heat treatment of the binder resin in the presence of peroxide is preferably carried out in a solution or a dispersion liquid in a solvent at a temperature not lower than the 10-hour half-life temperature of peroxide for 1 minute to 10 hours. , And more preferably 10 minutes to 5 hours.

【００１８】上記（ｂ）の方法では、結着剤として用い
る樹脂を、過酸化物とカルボン酸基とカルボン酸無水物
基から選ばれる少なくとも１つの官能基を有する不飽和
有機化合物の存在下加熱処理することにより、結着剤に
カルボン酸基あるいはカルボン酸無水物基がグラフト的
に導入される。In the method (b), the resin used as the binder is heated in the presence of an unsaturated organic compound having at least one functional group selected from a peroxide, a carboxylic acid group and a carboxylic acid anhydride group. By the treatment, a carboxylic acid group or a carboxylic acid anhydride group is graft-introduced into the binder.

【００１９】この場合、用いられるカルボン酸基あるい
はカルボン酸無水物基を有する不飽和有機化合物の例と
しては、アクリル酸、メタクリル酸、クロトン酸、マレ
イン酸、フマル酸、アルケニルコハク酸、アクリルアミ
ドグリコール酸、１，２−シクロヘキサンジカルボン酸
モノアリル等の不飽和カルボン酸、および無水マレイン
酸、無水アルケニルコハク酸などの不飽和カルボン酸無
水物、さらにこれらの誘導体がある。In this case, examples of the unsaturated organic compound having a carboxylic acid group or a carboxylic acid anhydride group used include acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, alkenylsuccinic acid, acrylamidoglycolic acid. , Unsaturated carboxylic acids such as monoallyl 1,2-cyclohexanedicarboxylic acid, and unsaturated carboxylic acid anhydrides such as maleic anhydride and alkenylsuccinic anhydride, and derivatives thereof.

【００２０】また、（ｂ）の方法で用いられる過酸化物
は特に限定されない。例として、パーオキシケタール
類、アルキルハイドロパーオキサイド類、ジアルキルパ
ーオキサイド類、アルキルパーオキシエステル類、ジア
シルパーオキサイド類、パーオキシジカーボネート類、
パーオキシエステル類等があるThe peroxide used in the method (b) is not particularly limited. Examples include peroxy ketals, alkyl hydroperoxides, dialkyl peroxides, alkyl peroxy esters, diacyl peroxides, peroxy dicarbonates,
Peroxyesters, etc.

【００２１】過酸化物存在下での結着剤樹脂の加熱処理
は、（ａ）の場合と同様に、溶液中あるいは溶媒への分
散液中で、過酸化物の１０時間半減期温度以上の温度
で、１分間〜１０時間行うことが望ましく、さらに望ま
しくは１０分間〜５時間である。The heat treatment of the binder resin in the presence of a peroxide is carried out in a solution or a dispersion liquid in a solvent at a temperature not lower than the 10-hour half-life temperature of the peroxide, as in the case of (a). The temperature is preferably 1 minute to 10 hours, more preferably 10 minutes to 5 hours.

【００２２】（ａ）および（ｂ）の方法において使用さ
れる溶剤は、水あるいはパーオキサイドに対して安定な
有機溶剤から選ばれ、特に限定されない。ただし、反応
を均一に且つ効率よく行うためには、結着剤樹脂が溶解
した状態でパーオキサイドとの反応を行うことが望まし
い。反応後、必要に応じて、沈澱としてポリマーを回収
し、アルコール等の溶剤で洗浄を行い、最後に乾燥して
目的のカルボン酸基を有する結着剤樹脂が得られる。The solvent used in the methods (a) and (b) is selected from organic solvents stable to water or peroxide and is not particularly limited. However, in order to carry out the reaction uniformly and efficiently, it is desirable to carry out the reaction with peroxide in a state where the binder resin is dissolved. After the reaction, if necessary, the polymer is recovered as a precipitate, washed with a solvent such as alcohol, and finally dried to obtain a desired binder resin having a carboxylic acid group.

【００２３】本発明において、結着剤に導入されるカル
ボン酸基あるいはカルボン酸無水物基の量は、固形酸価
で０．１〜３０ｍｇＫＯＨ／ｇ、さらに望ましくは０．
３〜１５ｍｇＫＯＨ／ｇである。カルボン酸基あるいは
カルボン酸無水物基の量がこれよりも少ない場合は、電
極活性物質と集電体との接着強度を改善させる効果が乏
しく、多すぎる場合は、電池の性能に悪影響を与える。In the present invention, the amount of the carboxylic acid group or carboxylic acid anhydride group introduced into the binder is 0.1 to 30 mgKOH / g in solid acid value, more preferably 0.
It is 3 to 15 mg KOH / g. When the amount of the carboxylic acid group or the carboxylic acid anhydride group is smaller than this, the effect of improving the adhesive strength between the electrode active substance and the current collector is poor, and when it is too large, the battery performance is adversely affected.

【００２４】本発明において、カルボン酸基あるいはカ
ルボン酸無水物基を有する上記のポリマーとこれらの官
能基を持たないポリマーとを混合して結着剤として用い
てもよい。この場合、前者の含有率は当該結着剤の５重
量％以上であることが望ましく、さらに望ましくは１０
重量％以上である。In the present invention, the above-mentioned polymer having a carboxylic acid group or a carboxylic acid anhydride group may be mixed with a polymer having no such functional group and used as a binder. In this case, the former content is preferably 5% by weight or more of the binder, and more preferably 10% by weight.
% By weight or more.

【００２５】本発明においては、所定量の電極活性物
質、および結着剤を溶媒の存在下で混練して得られたス
ラリーを電極集電体に塗布した後、乾燥後、必要に応じ
てプレスして電極が得られる。この場合、スラリーを塗
布後、必要に応じて、６０〜２５０℃、さらに望ましく
は８０〜２００℃で、１分間〜１０時間、加熱処理する
ことが望ましい。こうして得られる帯状電極を、帯状セ
パレータとともにロール状（渦巻状）に巻回し、巻回電
極体としてもよい。In the present invention, a slurry obtained by kneading a predetermined amount of an electrode active substance and a binder in the presence of a solvent is applied to an electrode current collector, dried, and then pressed if necessary. Then, an electrode is obtained. In this case, after applying the slurry, it is desirable to perform heat treatment at 60 to 250 ° C., and more desirably 80 to 200 ° C. for 1 minute to 10 hours, if necessary. The strip-shaped electrode obtained in this way may be wound in a roll (or spiral) together with the strip-shaped separator to form a wound electrode body.

【００２６】特に、結着剤がＰＶＤＦ系樹脂である場
合、電極集電体に塗布するスラリーを得るために用いら
れる溶媒は、Ｎ−メチルピロリドン、Ｎ，Ｎ−ジメチル
ホルムアミド、テトラヒドロフラン、ジメチルアセトア
ミド、ジメチルスルホキシド、ヘキサメチルスルホルア
ミド、テトラメチル尿素、アセトン、メチルエチルケト
ン等の有機溶媒や水であればよく、これらを単独で用い
ても、混合して用いてもよい。これらのうち、Ｎ−メチ
ルピロリドンが特に好んで用いられる。また、必要に応
じて分散剤を添加してもよい。この場合、ノニオン系の
分散剤が好んで用いられる。In particular, when the binder is a PVDF resin, the solvent used to obtain the slurry applied to the electrode current collector is N-methylpyrrolidone, N, N-dimethylformamide, tetrahydrofuran, dimethylacetamide, Any organic solvent such as dimethyl sulfoxide, hexamethyl sulfolamide, tetramethyl urea, acetone, methyl ethyl ketone and water may be used, and these may be used alone or in combination. Of these, N-methylpyrrolidone is particularly preferably used. Moreover, you may add a dispersing agent as needed. In this case, a nonionic dispersant is preferably used.

【００２７】またここで、電極活性物質に添加する結着
剤の量は、電極活性物質１００重量部に対して、１〜３
０重量部であることが望ましく、さらに望ましくは３〜
１５重量部である。この添加量が多すぎても少なすぎて
も高性能な電池を得ることができない。さらに、電極構
成物質層には、必要に応じて、導電性付与剤やその他添
加剤（酸化銅等）等を添加してもよい。Here, the amount of the binder added to the electrode active substance is 1 to 3 parts by weight with respect to 100 parts by weight of the electrode active substance.
It is preferably 0 parts by weight, more preferably 3 to
15 parts by weight. If the added amount is too large or too small, a high performance battery cannot be obtained. Further, a conductivity-imparting agent or other additives (such as copper oxide) may be added to the electrode constituent material layer as needed.

【００２８】本発明においては、結着剤へのカルボン酸
基あるいはカルボン酸無水物基の導入を電極作製時に同
時に行うことが可能である。この場合、電極活性物質、
結着剤、過酸化物、必要に応じてカルボン酸基あるいは
カルボン酸無水物基を有する不飽和有機化合物を溶媒の
存在下で混練して得られるスラリーを電極集電体に塗布
した後、過酸化物の１０時間半減期温度以上の温度で１
分間〜１０時間、さらに望ましくは１０分間〜５時間加
熱した後、乾燥すればよい。In the present invention, it is possible to introduce the carboxylic acid group or the carboxylic acid anhydride group into the binder at the same time when the electrode is produced. In this case, the electrode active substance,
A binder, a peroxide, and optionally an unsaturated organic compound having a carboxylic acid group or a carboxylic acid anhydride group are kneaded in the presence of a solvent, and the resulting slurry is applied to an electrode current collector, and then 1 above the 10 hour half-life temperature of the oxide
After heating for 10 minutes to 10 hours, more preferably 10 minutes to 5 hours, it may be dried.

【００２９】この場合、添加する過酸化物およびカルボ
ン酸基あるいはカルボン酸無水物基を有する不飽和有機
化合物の量は、いずれも、結着剤に対して０．１〜１０
重量％、望ましくは０．２〜５重量％、さらに望ましく
は０．３〜２重量％である。In this case, the amounts of the peroxide and the unsaturated organic compound having a carboxylic acid group or a carboxylic acid anhydride group to be added are both 0.1 to 10 relative to the binder.
%, Preferably 0.2 to 5% by weight, more preferably 0.3 to 2% by weight.

【００３０】以下、実施例により本発明を説明するが、
本発明は実施例により何ら限定されるものではない。The present invention will be described below with reference to examples.
The present invention is not limited at all by the examples.

【００３１】[0031]

【実施例】【Example】

【００３２】[0032]

【実施例１】ポリフッ化ビニリデン（エルフ・アトケム
社製、カイナー５００）１００重量部、無水マレイン酸
１０重量部、およびラウロイルパーオキサイド１０重量
部をＮ−メチルピロリドンに溶解してなる溶液を９０℃
で６時間加熱処理を行った後、反応液をメタノール中に
注ぎ、ポリマーを沈澱させた。このポリマーをメタノー
ルにて還流下２４時間ソックスレー抽出を行い、ポリマ
ー中に残留している未反応無水マレイン酸やパーオキサ
イドの分解物を除去した。このポリマーから作製したフ
ィルムについて、ＩＲスペクトルの１７００〜１８００
ｃｍ-1付近のカルボニル基による吸収の大きさから、別
途メタクリル酸メチルと無水マレイン酸との共重合体を
用いて作製した検量線をもとに算出したカルボニル基含
有量は３ｍｇＫＯＨ／ｇであった。Example 1 100 parts by weight of polyvinylidene fluoride (Kiner 500 manufactured by Elf Atchem), 10 parts by weight of maleic anhydride, and 10 parts by weight of lauroyl peroxide were dissolved in N-methylpyrrolidone to prepare a solution at 90 ° C.
After heating for 6 hours, the reaction solution was poured into methanol to precipitate the polymer. The polymer was subjected to Soxhlet extraction with methanol under reflux for 24 hours to remove unreacted maleic anhydride and peroxide decomposition products remaining in the polymer. A film made from this polymer has an IR spectrum of 1700 to 1800.
The carbonyl group content calculated from the magnitude of absorption by the carbonyl group near cm -1 based on a calibration curve separately prepared using a copolymer of methyl methacrylate and maleic anhydride was 3 mgKOH / g. It was

【００３３】負極活性物質担持体として石炭ピッチコー
クスをボールミルで粉砕したもの９０重量部および結着
剤として本実施例で得られたカルボン酸基を有するポリ
フッ化ビニリデン１０重量部を混合し、これをＮ−メチ
ルピロリドン中に分散させてスラリー（ペースト）状に
した。このスラリーを、厚さ２０μｍの銅箔の両面に塗
布し、１２０℃で３０分間放置した後、減圧乾燥、プレ
スを行い、厚さ１８０μｍ、幅２０ｍｍの負極を得た。90 parts by weight of coal pitch coke crushed by a ball mill as a negative electrode active material carrier and 10 parts by weight of polyvinylidene fluoride having a carboxylic acid group obtained in this example as a binder were mixed and mixed. It was dispersed in N-methylpyrrolidone to form a slurry (paste). This slurry was applied to both sides of a copper foil having a thickness of 20 μm, left at 120 ° C. for 30 minutes, dried under reduced pressure and pressed to obtain a negative electrode having a thickness of 180 μm and a width of 20 mm.

【００３４】この電極表面の電極活性物質をカッターナ
イフにて剥がしたところ、集電体上にかなりの電極活性
物質の付着残留物が認められ、電極活性物質と集電体と
の接着性が良好であることが確認された。When the electrode active substance on the surface of the electrode was peeled off with a cutter knife, a considerable amount of the electrode active substance adhesion residue was found on the current collector, and the adhesiveness between the electrode active substance and the current collector was good. Was confirmed.

【００３５】続いて、この負極と実施例１において作製
された正極を用い、実施例１と同様にして電池を作製し
た。実施例１と同様の条件で充放電試験を行ったとこ
ろ、１００サイクル目の放電容量は、１０サイクル目の
それの９０％であった。Then, using this negative electrode and the positive electrode produced in Example 1, a battery was produced in the same manner as in Example 1. When a charge / discharge test was conducted under the same conditions as in Example 1, the discharge capacity at the 100th cycle was 90% of that at the 10th cycle.

【００３６】[0036]

【実施例２】負極活性物質担持体として石炭ピッチコー
クスをボールミルで粉砕したもの９０重量部を、ポリフ
ッ化ビニリデン（エルフ・アトケム社製、カイナー７４
１）１０重量部、およびジコハク酸パーオキサイド０．
１重量部とをＮ−メチルピロリドンに溶解してなる溶液
に添加してスラリー（ペースト）状にした。このスラリ
ーを、厚さ２０μｍの銅箔の両面に塗布し、１２０℃で
１時間放置した後、減圧乾燥、プレスを行い厚さ１４０
μｍ、幅２０ｍｍの負極を得た。この電極層からテトラ
ヒドロフランを用いてＰＶＤＦを抽出し、実施例１と同
様の方法でカルボニル含有量を測定したところ、約２ｍ
ｇＫＯＨ／ｇであった。[Example 2] 90 parts by weight of coal pitch coke crushed by a ball mill as a negative electrode active material-supporting material was mixed with polyvinylidene fluoride (Kelfer 74 manufactured by Elf Atchem Co., Ltd.).
1) 10 parts by weight, and disuccinic acid peroxide 0.
1 part by weight was added to a solution prepared by dissolving N-methylpyrrolidone into a slurry (paste). This slurry is applied to both sides of a copper foil having a thickness of 20 μm, left at 120 ° C. for 1 hour, dried under reduced pressure and pressed to a thickness of 140.
A negative electrode having a thickness of 20 μm and a width of 20 mm was obtained. PVDF was extracted from this electrode layer using tetrahydrofuran, and the carbonyl content was measured by the same method as in Example 1 to find that it was about 2 m.
gKOH / g.

【００３７】次に、正極を次のようにして得た。正極活
性物質としてのＬｉＣｏＯ2９０重量部、導電剤として
のグラファイト６重量部、結着剤としてのポリフッ化ビ
ニリデン１０重量部、およびジコハク酸パーオキシド
０．１重量部を混合し、これをＮ−メチルピロリドン中
に分散させてスラリー（ペースト）状にした。このスラ
リーを、あらかじめ＃１０００のエメリー紙で磨き表面
を粗面化しておいた厚さ２０μｍのアルミニウム箔の両
面に塗布し、１２０℃で１時間放置した後、減圧乾燥、
プレスを行い、厚さ１７０μｍ、幅２０ｍｍの正極を得
た。Next, a positive electrode was obtained as follows. 90 parts by weight of LiCoO 2 as a positive electrode active material, 6 parts by weight of graphite as a conductive agent, 10 parts by weight of polyvinylidene fluoride as a binder, and 0.1 part by weight of disuccinic acid peroxide were mixed, and this was mixed with N-methyl. It was dispersed in pyrrolidone to form a slurry (paste). This slurry was applied to both sides of an aluminum foil having a thickness of 20 μm, which was previously polished with # 1000 emery paper to roughen the surface, left at 120 ° C. for 1 hour, and then dried under reduced pressure.
A positive electrode having a thickness of 170 μm and a width of 20 mm was obtained by pressing.

【００３８】これらの電極表面の電極活性物質をカッタ
ーナイフにて剥がしたところ、集電体上にかなりの電極
活性物質の付着残留物が認められ、電極活性物質と集電
体との接着性が良好であることが確認された。When the electrode active substance on the surface of these electrodes was peeled off with a cutter knife, a considerable amount of the electrode active substance adhering residue was observed on the current collector, and the adhesiveness between the electrode active substance and the current collector was confirmed. It was confirmed to be good.

【００３９】また、得られた負極、正極、およびセパレ
ータとしての厚さ２５μｍの多孔性ポリプロピレンフィ
ルムを用い、セパレータ、負極、セパレータ、正極、セ
パレータの順に積層した後、この積層体を渦巻状に巻回
することにより渦巻式の電極体を作製した。ついでこの
電極体のそれぞれの極にリード線を付けた後、ステンレ
スの缶に収容し、これに電解液としてプロピレンカーボ
ネートと１，２−ジメトキシエタンとの等容量混合溶媒
中にＬｉＰＦ6を１Ｍ溶解した溶液を注入した。Using the obtained negative electrode, positive electrode, and porous polypropylene film having a thickness of 25 μm as a separator, a separator, a negative electrode, a separator, a positive electrode, and a separator were laminated in this order, and then this laminated body was wound in a spiral shape. A spiral electrode body was produced by turning. Then, after attaching a lead wire to each electrode of the electrode body, the electrode body was housed in a stainless steel can, and 1 M of LiPF 6 was dissolved in an equal volume mixed solvent of propylene carbonate and 1,2-dimethoxyethane as an electrolytic solution. The injected solution was injected.

【００４０】充放電試験は、炭素１ｇあたり３０ｍＡの
電流密度で、初めに４．１Ｖまで充電を行い、続いて同
じ電流で２．５Ｖまで放電を行った。２回目以降もこれ
と同じ条件で充放電を繰り返し、放電容量にて電池の評
価を行った。その結果、１００サイクル目の放電容量
は、１０サイクル目のそれの９２％であった。In the charge / discharge test, a current density of 30 mA per 1 g of carbon was first charged to 4.1 V, and subsequently, the same current was discharged to 2.5 V. After the second time, charging and discharging were repeated under the same conditions, and the battery was evaluated by the discharge capacity. As a result, the discharge capacity at the 100th cycle was 92% of that at the 10th cycle.

【００４１】[0041]

【比較例１】実施例１において、負極と正極を作製する
際、ジコハク酸パーオキサイドを使用しなかった他は実
施例１と同様にして電極を作製した。これらの電極表面
の炭素ピッチコークスをカッターナイフにて剥がしたと
ころ、集電体表面には電極活性物質はほとんど残らなか
った。得られた電極を用い、実施例１に記載された方法
で電池を作製し、充放電試験を行ったところ、１００サ
イクル目の放電容量は１０サイクル目のそれの５０％で
あった。Comparative Example 1 An electrode was prepared in the same manner as in Example 1 except that the disuccinic acid peroxide was not used when preparing the negative electrode and the positive electrode. When the carbon pitch coke on the surface of these electrodes was peeled off with a cutter knife, almost no electrode active substance remained on the surface of the current collector. Using the obtained electrode, a battery was prepared by the method described in Example 1 and a charge / discharge test was conducted. The discharge capacity at 100th cycle was 50% of that at 10th cycle.

【００４２】[0042]

【発明の効果】本発明により、電極活性物質と集電体と
の接着強度が強い電極の作製が可能となる。これを二次
電池に適用すれば、充放電の繰り返しにより放電容量が
劣化しない二次電池が得られ、特に、リチウム二次電池
に有用である。EFFECTS OF THE INVENTION According to the present invention, it is possible to manufacture an electrode in which the adhesive strength between the electrode active substance and the current collector is high. When this is applied to a secondary battery, a secondary battery whose discharge capacity does not deteriorate due to repeated charging and discharging can be obtained, and it is particularly useful for a lithium secondary battery.

───────────────────────────────────────────────────── フロントページの続き (72)発明者 米倉 明季 京都府京都市下京区中堂寺粟田町１番地 エルフ・アトケム・ジャパン株式会社京都 テクニカルセンター内 (72)発明者 後藤 邦之 埼玉県浦和市曲本３丁目12番２号 コスモ 武蔵浦和306 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Aki Yonekura 1 Awata-cho, Nakado-ji, Shimogyo-ku, Kyoto, Japan Elf Atchem Japan Co., Ltd. Kyoto Technical Center (72) Inventor Kuniyuki Goto Urawa City, Saitama Prefecture 3-12-12 Cosmo Musashi Urawa 306

Claims (4)

【特許請求の範囲】[Claims] 【請求項１】集電体の表面に少なくとも電極活性物質と
結着剤からなる電極構成物質層が形成されている電池用
電極において、結着剤にカルボン酸基あるいはカルボン
酸無水物基が、（ａ）カルボン酸基とカルボン酸無水物
基から選ばれる少なくとも１つの官能基を有する有機過
酸化物の存在下で結着剤を加熱処理する方法、あるいは
（ｂ）カルボン酸基とカルボン酸無水物基から選ばれる
少なくとも１つの官能基を有する不飽和有機化合物と過
酸化物の存在下で結着剤を加熱処理する方法のいずれか
により導入されていることを特徴とする電池用電極。1. A battery electrode in which an electrode constituent substance layer comprising at least an electrode active substance and a binder is formed on the surface of a current collector, wherein the binder contains a carboxylic acid group or a carboxylic anhydride group. (A) a method of heat-treating the binder in the presence of an organic peroxide having at least one functional group selected from a carboxylic acid group and a carboxylic acid anhydride group; or (b) a carboxylic acid group and a carboxylic acid anhydride An electrode for a battery, which is introduced by any one of a method of heat-treating a binder in the presence of an unsaturated organic compound having at least one functional group selected from the physical groups and a peroxide. 【請求項２】結着剤の９０重量％以上がフッ素系樹脂で
ある請求項１記載の電池用電極。2. The battery electrode according to claim 1, wherein 90% by weight or more of the binder is a fluororesin. 【請求項３】電極活性物質、結着剤、および下記の
（ｃ）あるいは（ｄ）の添加物を溶媒の存在下で混練し
てスラリーを作製し、（ｃ）カルボン酸基とカルボン酸
無水物基から選ばれる少なくとも１つの官能基を有する
有機過酸化物を結着剤に対して０．１〜５重量％、
（ｄ）カルボン酸基とカルボン酸無水物基から選ばれる
少なくとも１つの官能基を有する不飽和有機化合物およ
び過酸化物を、それぞれ、結着剤に対し０．１〜１０重
量％および０．１〜５重量％、該スラリーを電極集電体
に塗布する前あるいは後に加熱処理することを特徴とす
る電池用電極の作製方法。3. An electrode active substance, a binder, and the following additives (c) or (d) are kneaded in the presence of a solvent to prepare a slurry, and (c) a carboxylic acid group and a carboxylic acid anhydride. 0.1 to 5 wt% of an organic peroxide having at least one functional group selected from the physical groups with respect to the binder,
(D) An unsaturated organic compound having at least one functional group selected from a carboxylic acid group and a carboxylic acid anhydride group, and a peroxide, respectively, in an amount of 0.1 to 10% by weight and 0.1 to the binder. A method for producing a battery electrode, characterized in that ˜5% by weight of the slurry is heat-treated before or after being applied to the electrode current collector. 【請求項４】結着剤の９０重量％以上がフッ素系樹脂で
ある請求項３記載の電池用電極の作製方法。4. The method for producing a battery electrode according to claim 3, wherein 90% by weight or more of the binder is a fluororesin.
JP7285924A 1995-11-02 1995-11-02 Electrode for battery and manufacture thereof Pending JPH09129237A (en)

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1998050479A1 (en) * 1997-05-02 1998-11-12 Elf Atochem S.A. A polyvinylidene fluoride metal-adhesive composition and an electrode for a battery
WO1999050919A1 (en) * 1998-03-26 1999-10-07 Tdk Corporation Method of manufacturing electrode for non-aqueous electrolytic cell
WO2013187522A1 (en) * 2012-06-15 2013-12-19 Jsr株式会社 Binder composition for electrodes
US9287563B2 (en) 2011-01-20 2016-03-15 Samsung Sdi Co., Ltd. Electrode for lithium secondary battery and lithium secondary battery including the same
JP2020087643A (en) * 2018-11-22 2020-06-04 カーリットホールディングス株式会社 Electrode for nonaqueous electrolyte secondary battery

Cited By (7)

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