JP2004047445A

JP2004047445A - Positive electrode active material for battery, manufacturing method for electrolytic manganese dioxide, and battery

Info

Publication number: JP2004047445A
Application number: JP2003134880A
Authority: JP
Inventors: Munetoshi Yamaguchi; 山口　宗利; Yasuhiro Ochi; 越智　康弘; Takeshi Nagaishi; 永石　剛; Naoki Kumada; 熊田　直樹; Takesato Asanuma; 浅沼　剛吏; Shigeo Hirayama; 平山　成生
Original assignee: Mitsui Mining and Smelting Co Ltd
Current assignee: Mitsui Mining and Smelting Co Ltd
Priority date: 2002-05-15
Filing date: 2003-05-13
Publication date: 2004-02-12
Anticipated expiration: 2023-05-13
Also published as: JP3712259B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a positive electrode active material for a battery comprising electrolytic manganese dioxide having high specific surface area, high potential, and improving high rate characteristics, high rate pulse characteristics, or the like as the positive electrode active material, to provide a manufacturing method for the electrolytic manganese dioxide, and to provide a battery using the positive electrode active material. <P>SOLUTION: In the positive electrode active material for the battery comprising electrolytic manganese dioxide, the electrolytic manganese dioxide contains 1.3-1.6 wt% sulfate radical. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、電解二酸化マンガンからなる電池用正極活物質及び電解二酸化マンガンの製造方法並びにその正極活物質を用いた電池に関する。
【０００２】
【従来の技術】
従来から電池用正極活物質の代表的な物質として二酸化マンガンが知られ、マンガン電池、アルカリマンガン電池などに使用されている。
【０００３】
このような電池用正極活物質として用いる二酸化マンガンを得る方法としては、硫酸マンガン及び硫酸溶液を電解液として電解する方法が知られている。しかしながら、このような電解二酸化マンガンでは電池の正極活物質に用いた場合、充分な特性を有する電池が得られないため様々な改良がなされている。
【０００４】
例えば、硫酸マンガン及び硫酸溶液にリン酸水溶液を添加した電解液を電解して、従来の電解二酸化マンガンと比較して高比表面積を有する電解二酸化マンガンを得る方法が開発されている（特許文献１参照）。
【０００５】
また、二酸化マンガンを硫酸溶液で洗滌して、二酸化マンガンの電位を上げる試みがなされている。
【０００６】
【特許文献１】
特開平２−５７６９３号公報（第１頁等）
【０００７】
【発明が解決しようとする課題】
電池の正極活物質として用いる二酸化マンガンは反応面積が大きく電位が高い方がよいとされており、電池の高性能化に伴い従来のものよりさらに高い比表面積、電位を有することが必要とされている。また、マンガン電池、アルカリマンガン電池等にはハイレート特性、ハイレートパルス特性の改善が求められている。
【０００８】
しかしながら、上述した従来の電解二酸化マンガンでは充分に満足できないという問題がある。
【０００９】
本発明は、このような事情に鑑み、高比表面積及び高電位を有し電池の正極活物質として用いてハイレート特性、ハイレートパルス特性等を向上させることができる電解二酸化マンガンからなる電池用正極活物質及び電解二酸化マンガンの製造方法並びにその正極活物質を用いた電池を提供することを課題とする。
【００１０】
【課題を解決するための手段】
前記課題を解決する本発明の第１の態様は、電解二酸化マンガンからなる電池用正極活物質において、前記電解二酸化マンガンが硫酸根を１．３〜１．６重量％含有することを特徴とする電池用正極活物質にある。
【００１１】
かかる第１の態様では、電解二酸化マンガンが硫酸根を含有しているので、高性能の電池用正極活物質を提供することができる。
【００１２】
本発明の第２の態様は、第１の態様において、前記電解二酸化マンガンの比表面積が４０〜６５ｍ^２／ｇであることを特徴とする電池用正極活物質にある。
【００１３】
かかる第２の態様では、電池用正極活物質となる電解二酸化マンガンの比表面積が４０〜６５ｍ^２／ｇと高いので、電池に用いると電池の高性能化を図ることができる。
【００１４】
本発明の第３の態様は、第１または２の態様において、前記電解二酸化マンガンの電位が２７０〜３２０ｍＶであることを特徴とする電池用正極活物質にある。
【００１５】
かかる第３の態様では、電池用正極活物質となる電解二酸化マンガンの電位が２７０〜３２０ｍＶと高いので、電池に用いると電池の高性能化を図ることができる。
【００１６】
本発明の第４の態様は、第１〜３の何れかの態様において、前記電解二酸化マンガンは硫酸マンガン及び硫酸溶液を電解液として、８５〜９５℃の電解温度、２０〜５０Ａ／ｍ^２の電解電流密度、５０〜１００ｇ／Ｌの硫酸濃度で電解して得たものであることを特徴とする電池用正極活物質にある。
【００１７】
かかる第４の態様では、前記の電解温度、電解電流密度、硫酸濃度で電解を行うことにより、高性能の電池用正極活物質を提供することができる。
【００１８】
本発明の第５の態様は、硫酸マンガン及び硫酸溶液を電解液として電解を行い電解二酸化マンガンを製造する方法において、８５〜９５℃の電解温度、２０〜５０Ａ／ｍ^２の電解電流密度、５０〜１００ｇ／Ｌの硫酸濃度で電解することを特徴とする電解二酸化マンガンの製造方法にある。
【００１９】
かかる第５の態様では、前記の電解温度、電解電流密度、硫酸濃度で電解を行い電解二酸化マンガンを得ることにより、高性能の電池用正極活物質を提供することができる。
【００２０】
本発明の第６の態様は、第５の態様において、前記電解二酸化マンガンの硫酸根の含有量が１．３〜１．６重量％であることを特徴とする電解二酸化マンガンの製造方法にある。
【００２１】
かかる第６の態様では、電解二酸化マンガンが硫酸根を１．３〜１．６重量％含有しているので、高性能の電池用正極活物質となる。
【００２２】
本発明の第７の態様は、第５または６の態様において、前記電解二酸化マンガンの比表面積が４０〜６５ｍ^２／ｇであることを特徴とする電解二酸化マンガンの製造方法にある。
【００２３】
かかる第７の態様では、電解二酸化マンガンの比表面積が４０〜６５ｍ^２／ｇと高いので、電池に用いると電池の高性能化を図ることができる。
【００２４】
本発明の第８の態様は、第５〜７の何れかの態様において、前記電解二酸化マンガンの電位が２７０〜３２０ｍＶであることを特徴とする電解二酸化マンガンの製造方法にある。
【００２５】
かかる第８の態様では、電解二酸化マンガンの電位が２７０〜３２０ｍＶと高いので、電池に用いると電池の高性能化を図ることができる。
【００２６】
本発明の第９の態様は、第１〜４の何れかの態様の電池用正極活物質を用いたことを特徴とする電池にある。
【００２７】
かかる第９の態様では、電解二酸化マンガンが硫酸根を１．３〜１．６重量％含有した電池用正極活物質を用いるので、優れたハイレート特性やハイレートパルス特性等を有する電池を提供することができる。
【００２８】
以下、本発明の構成をさらに詳細に説明する。
【００２９】
本発明の電池用正極活物質は電解法により製造された電解二酸化マンガンであって、電解により製造された時点で硫酸根（ＳＯ_４）を含有するものである。すなわち、かかる電池用正極活物質に事後的に硫酸根を添加したものとは異なり、二酸化マンガンの内部に硫酸根が含有されたものである。ここで、硫酸根が内部に含有された状態とは、例えば、二酸化マンガンを水酸化ナトリウムなどのアルカリ性溶液で洗滌した場合、除去される硫酸根が観察されない状態であり、硫酸根が二酸化マンガンに一体的に固溶しているものと推測される。
【００３０】
本発明の電解二酸化マンガンが含有する硫酸根の割合は、１．３〜１．６重量％であることが好ましい。硫酸根の含有量が１．３重量％より低いと電解二酸化マンガンの電位を向上させる効果は顕著でなくなり、また、硫酸根の含有量の増加とともに電位は高くなるが、含有量が１．６重量％より高くなると電位はむしろ低くなるためである。このように電解二酸化マンガンが硫酸根を１．３〜１．６重量％含有すると、電位が２７０〜３２０ｍＶと高くなり、高性能な電池用正極活物質となる。ここで本発明における電解二酸化マンガンの電位は、例えば、１０規定の水酸化カリウム水溶液中にて、水銀／酸化水銀電極を参照電極として用い、２１±１℃で測定される電位差をいう。
【００３１】
また、本発明の電解二酸化マンガンの比表面積は、４０〜６５ｍ^２／ｇであることが好ましい。比表面積が４０ｍ^２／ｇより低いと、電池用正極活物質として用いた場合、ハイレート特性を向上させる効果は顕著でなくなり、６５ｍ^２／ｇより高いと充填性が悪化し、ローレート特性が悪化するためである。ここで比表面積は、例えば、ＢＥＴの一点法によって測定される。測定条件の例としては以下の通りである。
【００３２】
測定装置：カンタクロム社製モノソーブ
サンプル重量：０．１５ｇ
測定前の脱ガス条件：２５０℃にて窒素ガスを３０ｃｃ／分の流量で導入しながら２０分間加熱
吸着測定温度：２１±１℃から７７Ｋまで冷却
脱離測定温度：７７Ｋから２１±１℃まで昇温
【００３３】
電解二酸化マンガンに硫酸根を含有させるには、例えば硫酸マンガン及び硫酸溶液からなる電解液を電解する。これにより、硫酸根を一体的に含有する電解二酸化マンガンを得ることができる。
【００３４】
その際に、電解温度、電解電流密度、硫酸濃度を好ましい条件で行うことにより、所望の硫酸根含有量および比表面積の電解二酸化マンガンを得ることができる。
【００３５】
例えば、電解温度は８５〜９５℃であることが好ましい。電解温度が８５℃より低いと比表面積が高くなり、電池用正極活物質として用いた場合、ローレート特性が悪化し、９５℃より高いと比表面積が低くなりハイレート特性を向上させる効果は顕著でなくなるためである。また、電解電流密度は２０〜５０Ａ／ｍ^２であることが好ましい。電解電流密度が２０Ａ／ｍ^２より低いと比表面積が低くなり、電池用正極活物質として用いた場合、ハイレート特性を向上させる効果が顕著でなくなり、５０Ａ／ｍ^２より高いと電解二酸化マンガンに含有される硫酸根が低下し、電位が下がり電池特性が低下するためである。さらに、電解液の硫酸濃度は５０〜１００ｇ／Ｌであることが好ましい。硫酸濃度が５０ｇ／Ｌより低いと電解二酸化マンガンに含有される硫酸根が低下し、電位が下がり電池用正極活物質として用いた場合、電池特性が悪化し、１００ｇ／Ｌより高いと含有される硫酸根が上がり過ぎ、電位が下がり電池特性が低下するためである。
【００３６】
他の電解の条件については、従来から知られている硫酸マンガン及び硫酸溶液からなる電解液を電解して電解二酸化マンガンを得る方法を適用すればよい。例えば、電解液中のマンガン濃度は２０〜５０ｇ／Ｌが一般的である。また、電極として陽極にはチタン等、陰極にはカーボン等を用いることができる。
【００３７】
このようにして得た本発明の電解二酸化マンガンは１．３〜１．６重量％の硫酸根を含有するので、電位が２７０〜３２０ｍＶと高くなる。また、さらに比表面積が４０〜６５ｍ^２／ｇと高くなると、高性能な電池用正極活物質となる。
【００３８】
上述の電解二酸化マンガンからなる正極活物質は、マンガン電池、アルカリマンガン電池等の正極活物質として好適に用いることができる。
【００３９】
電池の負極活物質は従来から知られているものでよく、特に限定されないが、マンガン電池、アルカリマンガン電池の場合は亜鉛等を用いる。
【００４０】
電池を構成する電解液も従来から知られているものでよく、特に限定されないが、マンガン電池では塩化亜鉛又は塩化アンモニウム、アルカリマンガン電池では水酸化カリウム等を用いる。
【００４１】
本発明では、電解二酸化マンガンが硫酸根を１．３〜１．６重量％含有するので、電位が２７０〜３２０ｍＶと高く、また、比表面積を４０〜６５ｍ^２／ｇと高くすると、電池の正極活物質として用いた場合に電池のハイレート特性及びハイレートパルス特性を改善させることができる。
【００４２】
したがって、硫酸根を１．３〜１．６重量％含有し且つ比表面積を４０〜６５ｍ^２／ｇとするのが好ましく、この製造条件は上述した範囲から適宜選択すればよいが、特に、８５〜９５℃の電解温度、２０〜５０Ａ／ｍ^２の電解電流密度、５０〜１００ｇ／Ｌの硫酸濃度を満足すると、確実に硫酸根を１．３〜１．６重量％含有し且つ比表面積が４０〜６５ｍ^２／ｇである電解二酸化マンガンを製造することができる。
【００４３】
よって、本発明に係る製造方法は、８５〜９５℃の電解温度、２０〜５０Ａ／ｍ^２の電解電流密度、５０〜１００ｇ／Ｌの硫酸濃度の条件で電解するというものである。
【００４４】
電解二酸化マンガンの硫酸根含有量が１．３〜１．６重量％で且つ比表面積が４０〜６５ｍ^２／ｇである正極活物質をアルカリマンガン電池に用いると、特に、電池のハイレートパルス特性を１０〜２０％程度向上させることができる。このようなハイレートパルス特性に優れたアルカリマンガン電池は、例えばデジタルカメラ等に好適に使用することができる。
【００４５】
【発明の実施の形態】
次に、本発明を実施例及び比較例に基づいてさらに詳細に説明する。
【００４６】
（実施例１）
加温装置を設けた５Ｌビーカーを電解槽とし、陽極としてチタン板を、陰極として黒鉛板をそれぞれ交互に懸吊し、電解槽の底部に硫酸マンガンからなる電解補給液の導入管を設けたものを使用した。この電解補給液を前記電解槽に注入しながら、電解するに際して電解液の組成をマンガン４０ｇ／Ｌ、硫酸濃度７５ｇ／Ｌとなるように調整し、電解浴の温度を９０℃に保ち電流密度３５Ａ／ｍ^２で２０日間電解した。
【００４７】
電解終了後、電解二酸化マンガンが電着した陽極板を取り出し、常法に従って後処理を実施して、実施例１の電解二酸化マンガンを得た。
【００４８】
（実施例２）
電解浴の温度を８５℃と低くした以外は実施例１と同様に行って、実施例２の電解二酸化マンガンを得た。
【００４９】
（実施例３）
電解浴の温度を９５℃と高くした以外は実施例１と同様に行って、実施例３の電解二酸化マンガンを得た。
【００５０】
（実施例４）
電流密度を２０Ａ／ｍ^２と低くした以外は実施例１と同様に行って、実施例４の電解二酸化マンガンを得た。
【００５１】
（実施例５）
電流密度を５０Ａ／ｍ^２と高くした以外は実施例１と同様に行って、実施例５の電解二酸化マンガンを得た。
【００５２】
（実施例６）
電解液の硫酸濃度を５０ｇ／Ｌと低くした以外は実施例１と同様に行って、実施例６の電解二酸化マンガンを得た。
【００５３】
（実施例７）
電解液の硫酸濃度を１００ｇ／Ｌと高くした以外は実施例１と同様に行って、実施例７の電解二酸化マンガンを得た。
【００５４】
（実施例８）
電解浴の温度を８０℃と低くした以外は実施例１と同様に行って、実施例８の電解二酸化マンガンを得た。
【００５５】
（実施例９）
電解浴の温度を９８℃と高くした以外は実施例１と同様に行って、実施例９の電解二酸化マンガンを得た。
【００５６】
（実施例１０）
電流密度を１５Ａ／ｍ^２と低くした以外は実施例１と同様に行って、実施例１０の電解二酸化マンガンを得た。
【００５７】
（比較例１）
電流密度を５５Ａ／ｍ^２と高くした以外は実施例１と同様に行って、比較例１の電解二酸化マンガンを得た。
【００５８】
（比較例２）
電解液の硫酸濃度を４５ｇ／Ｌと低くした以外は実施例１と同様に行って、比較例２の電解二酸化マンガンを得た。
【００５９】
（比較例３）
電解液の硫酸濃度を１０５ｇ／Ｌと高くした以外は実施例１と同様に行って、比較例３の電解二酸化マンガンを得た。
【００６０】
（試験例１）
実施例１〜１０及び比較例１〜３で得られた電解二酸化マンガンの硫酸根、電位及び比表面積を測定した。測定結果を表１に示す。なお、電解二酸化マンガンの硫酸根は、通常のＩＣＰ発光分光分析法で測定した。また、電位の測定は、ニッケルからなる缶に圧着した電解二酸化マンガンを一昼夜水酸化カリウム水溶液中に浸漬した後、水銀／酸化水銀電極との電位差を測定した。比表面積の測定は、窒素通気中で２５０℃で２０分間、電解二酸化マンガンを加熱し、細孔内の水分を除去後、ＢＥＴ１点法で行った。
【００６１】
【表１】

【００６２】
表１に示すように、実施例１〜１０の電解二酸化マンガンは、硫酸根が１．３〜１．６重量％であるため、２７０〜３２０ｍＶと高電位であった。特に、実施例１〜７の電解二酸化マンガンは、さらに、比表面積は４０〜６５ｍ^２／ｇであった。
【００６３】
また、実施例１〜７の結果から、電解温度８５〜９５℃、電流密度２０〜５０Ａ／ｍ^２、硫酸濃度５０〜１００ｇ／Ｌの電解条件で製造すれば、硫酸根含有量１．３〜１．６重量％、電位２７０〜３２０ｍＶ、比表面積４０〜６５ｍ^２／ｇの電解二酸化マンガンとなることがわかった。
【００６４】
（実施例１Ａ〜１０Ａ）
実施例１〜１０の電解二酸化マンガンを正極活物質としてＬＲ６（単３）型のアルカリマンガン電池を作製した。ここで、電池の電解液としては濃度４０％の水酸化カリウム水溶液に酸化亜鉛を飽和させたものに、ゲル化剤としてカルボメトキシセルロースとポリアクリル酸ソーダを１．０％程度加えたものを用いた。また、負極活物質として亜鉛粉末３．０ｇを用い、この負極活物質と上述した電解液１．５ｇとを混合してゲル状化したものをそのまま負極材とした。このように作製したアルカリマンガン電池の縦断面図を図１に示す。
【００６５】
図１に示すように、本発明にかかるアルカリマンガン電池は、正極缶１の内側に配置された電解二酸化マンガンからなる正極活物質２と、正極活物質２の内側にセパレーター３を介して配置されたゲル状亜鉛粉末からなる負極材４とを具備する。負極材４内には負極集電体５が挿入され、この負極集電体５が正極缶１の下部を塞ぐ封口体６を貫通して当該封口体６の下方に設けられた負極底板７と接合されている。一方、正極缶１の上側には正極端子となるキャップ８が設けられている。キャップ８及び負極底板７を上下から挟む絶縁リング９、１０が設けられ、これら絶縁リング９、１０を介してキャップ８及び負極底板７を固定すると共に、正極缶１の外周を覆うように熱収縮性樹脂チューブ１１及びこれを覆う外装缶１２が設けられている。
【００６６】
（比較例１Ａ〜３Ａ）
比較例１〜３の電解二酸化マンガンを正極活物質として、実施例１Ａ〜１０Ａと同様にアルカリマンガン電池を作製した。
【００６７】
（試験例２）
実施例１Ａ〜１０Ａ及び比較例１Ａ〜３Ａのアルカリマンガン電池について、２０℃、放電電流１０ｍＡ（ローレート）で放電を行い、カット電圧（終止電圧）０．９Ｖまでの放電時間を測定した。実施例９Ａの値を１００％としてローレート特性を評価した。
【００６８】
（試験例３）
実施例１Ａ〜１０Ａ及び比較例１Ａ〜３Ａのアルカリマンガン電池について、２０℃、放電電流１０００ｍＡ（ハイレート）で放電を行い、カット電圧（終止電圧）０．９Ｖまでの放電時間を測定した。実施例９Ａの値を１００％としてハイレート特性を評価した。
【００６９】
（試験例４）
実施例１Ａ〜１０Ａ及び比較例１Ａ〜３Ａのアルカリマンガン電池について、２０℃、放電電流１０００ｍＡ（ハイレート）で１０秒ＯＮ、５０秒ＯＦＦのパルス繰り返し放電を行い、カット電圧（終止電圧）０．９Ｖまでのパルス回数を測定した。実施例９Ａの値を１００％としてハイレートパルス特性を評価した。試験例２〜４の測定結果を表２に示す。なお、表１に記載の電解二酸化マンガンの硫酸根含有量、比表面積についても併せて記載した。
【００７０】
【表２】

【００７１】
表２に示すように、硫酸根含有量が１．３〜１．６重量％である電解二酸化マンガンを正極活物質とした実施例１Ａ〜１０Ａでは、比較例１Ａ〜３Ａと比較して、概ね良好なハイレート特性及びハイレートパルス特性を示した。特に、電解二酸化マンガンの比表面積が４０〜６５ｍ^２／ｇである実施例１Ａ〜７Ａでは、優れたハイレート特性及びハイレートパルス特性を示し、比表面積が４０〜６５ｍ^２／ｇの範囲外である実施例８Ａ〜１０Ａと比較しても良好であった。
【００７２】
表１及び表２に示すように、電解温度８５〜９５℃で電解した実施例１Ａ〜３Ａは、９８℃で電解した実施例９Ａと比較して、アルカリマンガン電池のハイレート特性は５〜１０％、ハイレートパルス特性は１０〜２０％向上した。なお、８０℃で電解した実施例８Ａでは、実施例１Ａ〜３Ａ及び実施例９Ａと比較してローレート特性が著しく低下した。
【００７３】
また、電流密度２０〜５０Ａ／ｍ^２で電解した実施例１Ａ、４Ａ及び５Ａは、１５Ａ／ｍ^２で電解した実施例１０Ａと比較してハイレートパルス特性が１０〜１８％向上した。なお、５５Ａ／ｍ^２で電解した比較例１Ａは、実施例１Ａ、４Ａ、５Ａ及び１０Ａと比較して、すべての電池特性で同等以下であった。
【００７４】
さらに、硫酸濃度５０〜１００ｇ／Ｌで電解した実施例１Ａ、６Ａ及び７Ａは、４５ｇ／Ｌで電解した比較例２Ａと比較してハイレートパルス特性が１５％向上した。なお、１０５ｇ／Ｌで電解した比較例３Ａは、実施例１Ａ、６Ａ及び７Ａ、比較例２Ａと比較して、すべての電池特性が劣っていた。
【００７５】
したがって、実施例１Ａ〜７Ａのように、電解温度８５〜９５℃、電流密度２０〜５０Ａ／ｍ^２、硫酸濃度５０〜１００ｇ／Ｌの電解条件で製造して得た、硫酸根含有量１．３〜１．６重量％、電位２７０〜３２０ｍＶ、比表面積４０〜６５ｍ^２／ｇである電解二酸化マンガンを正極活物質とすると、ハイレート特性及びハイレートパルス特性に優れたアルカリマンガン電池となることが分かった。
【００７６】
【発明の効果】
以上説明したように、本発明によると、電解二酸化マンガンが硫酸根を１．３〜１．６重量％含有するため、高電位の電池用正極活物質とすることができ、さらに、比表面積を４０〜６５ｍ^２／ｇと高くすると高性能な電池用正極活物質を提供することができる。また、電解温度８５〜９５℃、電流密度２０〜５０Ａ／ｍ^２、硫酸濃度５０〜１００ｇ／Ｌの電解条件で電解を行うことにより、硫酸根１．３〜１．６重量％、電位２７０〜３２０ｍＶ、比表面積４０〜６５ｍ^２／ｇの電解二酸化マンガンを得ることができる。さらに、この電解二酸化マンガンを電池の正極活物質として用いるとハイレート特性及びハイレートパルス特性等に優れた電池を得ることができるという効果を奏する。
【図面の簡単な説明】
【図１】本発明に係るアルカリマンガン電池の断面図である。
【符号の説明】
１　正極缶
２　正極活物質
３　セパレータ
４　負極材
５　負極集電体
６　封口体
７　負極底板
８　キャップ
９、１０　絶縁リング
１１　熱収縮性樹脂チューブ
１２　外装缶[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a battery positive electrode active material comprising electrolytic manganese dioxide, a method for producing electrolytic manganese dioxide, and a battery using the positive electrode active material.
[0002]
[Prior art]
Conventionally, manganese dioxide has been known as a typical positive electrode active material for batteries, and is used for manganese batteries, alkaline manganese batteries, and the like.
[0003]
As a method of obtaining manganese dioxide used as such a positive electrode active material for a battery, there is known a method of performing electrolysis using a manganese sulfate and a sulfuric acid solution as an electrolytic solution. However, when such electrolytic manganese dioxide is used as a positive electrode active material of a battery, a battery having sufficient characteristics cannot be obtained, and thus various improvements have been made.
[0004]
For example, a method has been developed in which an electrolytic solution obtained by adding a phosphoric acid aqueous solution to manganese sulfate and a sulfuric acid solution is electrolyzed to obtain electrolytic manganese dioxide having a higher specific surface area than conventional electrolytic manganese dioxide (Patent Document 1). reference).
[0005]
Attempts have also been made to increase the potential of manganese dioxide by washing the manganese dioxide with a sulfuric acid solution.
[0006]
[Patent Document 1]
JP-A-2-57693 (page 1, etc.)
[0007]
[Problems to be solved by the invention]
It is said that manganese dioxide used as a positive electrode active material of a battery has a large reaction area and a high potential, and it is necessary to have a higher specific surface area and a higher potential than conventional ones as the performance of the battery increases. I have. In addition, manganese batteries, alkaline manganese batteries, and the like are required to have improved high-rate characteristics and high-rate pulse characteristics.
[0008]
However, there is a problem that the above-mentioned conventional electrolytic manganese dioxide cannot be sufficiently satisfied.
[0009]
In view of such circumstances, the present invention provides a positive electrode active material for a battery made of electrolytic manganese dioxide, which has a high specific surface area and a high potential, and can be used as a positive electrode active material of a battery to improve high rate characteristics, high rate pulse characteristics, and the like. It is an object to provide a method for producing a substance and electrolytic manganese dioxide, and a battery using the positive electrode active material.
[0010]
[Means for Solving the Problems]
According to a first aspect of the present invention for solving the above-mentioned problems, in the positive electrode active material for a battery comprising electrolytic manganese dioxide, the electrolytic manganese dioxide contains 1.3 to 1.6% by weight of a sulfate group. It is in the positive electrode active material for batteries.
[0011]
In the first aspect, since the electrolytic manganese dioxide contains a sulfate group, a high-performance positive electrode active material for a battery can be provided.
[0012]
A second aspect of the present invention is the positive electrode active material for a battery according to the first aspect, wherein the electrolytic manganese dioxide has a specific surface area of 40 to 65 m ² / g.
[0013]
In the second aspect, since the specific surface area of the electrolytic manganese dioxide serving as the battery positive electrode active material is as high as 40 to 65 m ² / g, the use of the battery can improve the performance of the battery.
[0014]
A third aspect of the present invention is the positive electrode active material for a battery according to the first or second aspect, wherein the potential of the electrolytic manganese dioxide is 270 to 320 mV.
[0015]
In the third aspect, the potential of the electrolytic manganese dioxide serving as the positive electrode active material for a battery is as high as 270 to 320 mV. Therefore, when used in a battery, the performance of the battery can be improved.
[0016]
According to a fourth aspect of the present invention, in any one of the first to third aspects, the electrolytic manganese dioxide has an electrolysis temperature of 85 to 95 ° C. and an electrolytic temperature of 20 to 50 A / m ^{2 using} manganese sulfate and a sulfuric acid solution as an electrolytic solution. A positive electrode active material for a battery, which is obtained by electrolysis at an electrolytic current density of 50 to 100 g / L of sulfuric acid.
[0017]
In the fourth aspect, by performing electrolysis at the above-described electrolysis temperature, electrolysis current density, and sulfuric acid concentration, a high-performance positive electrode active material for a battery can be provided.
[0018]
According to a fifth aspect of the present invention, there is provided a method for producing electrolytic manganese dioxide by performing electrolysis using manganese sulfate and a sulfuric acid solution as an electrolytic solution, comprising: an electrolytic temperature of 85 to 95 ° C., an electrolytic current density of 20 to 50 A / m ² , A method for producing electrolytic manganese dioxide, characterized in that electrolysis is performed at a sulfuric acid concentration of 100 g / L.
[0019]
In the fifth aspect, a high-performance positive electrode active material for a battery can be provided by performing electrolysis at the above-described electrolysis temperature, electrolysis current density, and sulfuric acid concentration to obtain electrolytic manganese dioxide.
[0020]
A sixth aspect of the present invention is the method for producing electrolytic manganese dioxide according to the fifth aspect, wherein the content of sulfate in the electrolytic manganese dioxide is 1.3 to 1.6% by weight. .
[0021]
In the sixth aspect, since the electrolytic manganese dioxide contains 1.3 to 1.6% by weight of sulfate, it becomes a high-performance positive electrode active material for a battery.
[0022]
A seventh aspect of the present invention is the method for producing electrolytic manganese dioxide according to the fifth or sixth aspect, wherein the specific surface area of the electrolytic manganese dioxide is 40 to 65 m ² / g.
[0023]
In the seventh aspect, the specific surface area of the electrolytic manganese dioxide is as high as 40 to 65 m ² / g, so that when used in a battery, the performance of the battery can be improved.
[0024]
An eighth aspect of the present invention is the method for producing electrolytic manganese dioxide according to any one of the fifth to seventh aspects, wherein the potential of the electrolytic manganese dioxide is 270 to 320 mV.
[0025]
In the eighth aspect, since the potential of the electrolytic manganese dioxide is as high as 270 to 320 mV, the performance of the battery can be improved when used in a battery.
[0026]
A ninth aspect of the present invention is a battery using the positive electrode active material for a battery according to any one of the first to fourth aspects.
[0027]
In the ninth aspect, since the electrolytic manganese dioxide uses the positive electrode active material for a battery containing 1.3 to 1.6% by weight of sulfate, a battery having excellent high-rate characteristics, high-rate pulse characteristics, and the like is provided. Can be.
[0028]
Hereinafter, the configuration of the present invention will be described in more detail.
[0029]
The positive electrode active material for a battery of the present invention is electrolytic manganese dioxide produced by an electrolytic method, and contains sulfate (SO ₄ ) when produced by electrolysis. That is, unlike the positive electrode active material for a battery in which a sulfate group is added afterwards, the manganese dioxide contains a sulfate group inside. Here, the state in which sulfate is contained in the interior means, for example, that when manganese dioxide is washed with an alkaline solution such as sodium hydroxide, the removed sulfate is not observed, and the sulfate is converted into manganese dioxide. It is presumed that they were integrally dissolved.
[0030]
The proportion of sulfate groups contained in the electrolytic manganese dioxide of the present invention is preferably 1.3 to 1.6% by weight. If the content of sulfate is less than 1.3% by weight, the effect of improving the potential of electrolytic manganese dioxide is not significant, and the potential increases with the content of sulfate, but the content is 1.6. This is because the electric potential becomes rather low when the amount is higher than% by weight. When the electrolytic manganese dioxide contains 1.3 to 1.6% by weight of the sulfate group, the potential is increased to 270 to 320 mV, and a high-performance positive electrode active material for a battery is obtained. Here, the potential of the electrolytic manganese dioxide in the present invention refers to, for example, a potential difference measured at 21 ± 1 ° C. in a 10 N aqueous potassium hydroxide solution using a mercury / mercury oxide electrode as a reference electrode.
[0031]
Further, the specific surface area of the electrolytic manganese dioxide of the present invention is preferably from 40 to 65 m ² / g. When the specific surface area is lower than 40 m ² / g, when used as a positive electrode active material for a battery, the effect of improving the high rate characteristics is not significant, and when the specific surface area is higher than 65 m ² / g, the filling property is deteriorated and the low rate characteristics are deteriorated. That's why. Here, the specific surface area is measured by, for example, the one-point method of BET. Examples of the measurement conditions are as follows.
[0032]
Measuring device: Monosorb sample made by Kantachrome Sample weight: 0.15 g
Degassing conditions before measurement: 250 ° C. while adsorbing nitrogen gas at a flow rate of 30 cc / min. For 20 minutes Adsorption measurement temperature: From 21 ± 1 ° C. to 77K Cooling desorption measurement temperature: From 77K to 21 ± 1 ° C. Heating [0033]
In order to make the electrolytic manganese dioxide contain a sulfate group, for example, an electrolytic solution composed of a manganese sulfate and a sulfuric acid solution is electrolyzed. As a result, electrolytic manganese dioxide containing a sulfate group integrally can be obtained.
[0034]
At this time, by performing the electrolysis temperature, electrolysis current density, and sulfuric acid concentration under preferable conditions, it is possible to obtain electrolytic manganese dioxide having a desired sulfate group content and specific surface area.
[0035]
For example, the electrolysis temperature is preferably from 85 to 95 ° C. When the electrolysis temperature is lower than 85 ° C., the specific surface area increases, and when used as a positive electrode active material for a battery, the low rate characteristics deteriorate. When the electrolysis temperature is higher than 95 ° C., the specific surface area decreases and the effect of improving the high rate characteristics is not significant. That's why. Further, the electrolysis current density is preferably ²⁰ to 50 A / m ² . When the electrolytic current density is lower than 20 A / m ² , the specific surface area is low, and when used as a positive electrode active material for a battery, the effect of improving the high rate characteristics is not significant. When the electrolytic current density is higher than 50 A / m ² , the electrolytic manganese dioxide contains This is because the sulfate group to be used decreases, the potential decreases, and the battery characteristics deteriorate. Further, the sulfuric acid concentration of the electrolytic solution is preferably 50 to 100 g / L. When the sulfuric acid concentration is lower than 50 g / L, the sulfate groups contained in the electrolytic manganese dioxide are reduced, and the potential is lowered. When used as a positive electrode active material for a battery, the battery characteristics are deteriorated. This is because the sulfate groups rise too much, the potential drops, and the battery characteristics deteriorate.
[0036]
Regarding other electrolysis conditions, a conventionally known method of electrolyzing an electrolytic solution composed of manganese sulfate and a sulfuric acid solution to obtain electrolytic manganese dioxide may be applied. For example, the manganese concentration in the electrolyte is generally 20 to 50 g / L. In addition, titanium or the like can be used for an anode and carbon or the like can be used for a cathode as an electrode.
[0037]
Since the thus obtained electrolytic manganese dioxide of the present invention contains 1.3 to 1.6% by weight of sulfate, the electric potential is as high as 270 to 320 mV. Further, when the specific surface area further increases to 40 to 65 m ² / g, it becomes a high-performance positive electrode active material for a battery.
[0038]
The above-described positive electrode active material composed of electrolytic manganese dioxide can be suitably used as a positive electrode active material for a manganese battery, an alkaline manganese battery, or the like.
[0039]
The negative electrode active material of the battery may be a conventionally known material, and is not particularly limited. In the case of a manganese battery or an alkaline manganese battery, zinc or the like is used.
[0040]
The electrolyte constituting the battery may be a conventionally known electrolyte, and is not particularly limited. For a manganese battery, zinc chloride or ammonium chloride is used, and for an alkaline manganese battery, potassium hydroxide or the like is used.
[0041]
In the present invention, since the electrolytic manganese dioxide contains 1.3 to 1.6% by weight of sulfate, the potential is as high as 270 to 320 mV and the specific surface area is as high as 40 to 65 m ² / g. When used as an active material, high-rate characteristics and high-rate pulse characteristics of a battery can be improved.
[0042]
Therefore, it is preferable to contain 1.3 to 1.6% by weight of a sulfate group and to have a specific surface area of 40 to 65 m ² / g, and the production conditions may be appropriately selected from the above-mentioned range. When an electrolysis temperature of ９５95 ° C. is satisfied, an electrolysis current density of ^{20 to} 50 A / m ² , and a sulfuric acid concentration of 50 to 100 g / L are satisfied, the sulfate group is surely contained in an amount of 1.3 to 1.6% by weight and the specific surface area is increased. Electrolytic manganese dioxide of 40 to 65 m ² / g can be produced.
[0043]
Therefore, in the production method according to the present invention, the electrolysis is performed under the conditions of an electrolysis temperature of 85 to 95 ° C., an electrolysis current density of 20 to 50 A / m ² , and a sulfuric acid concentration of 50 to 100 g / L.
[0044]
When a positive electrode active material having a sulfate content of 1.3 to 1.6% by weight and a specific surface area of 40 to 65 m ² / g of the electrolytic manganese dioxide is used for an alkaline manganese battery, particularly, the high-rate pulse characteristics of the battery are reduced. It can be improved by about 10 to 20%. Such an alkaline manganese battery having excellent high-rate pulse characteristics can be suitably used for, for example, a digital camera.
[0045]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, the present invention will be described in more detail based on examples and comparative examples.
[0046]
(Example 1)
A 5 L beaker equipped with a heating device is used as an electrolytic cell, a titanium plate is alternately suspended as a positive electrode, and a graphite plate is suspended as a negative electrode. An introduction tube for an electrolytic replenisher made of manganese sulfate is provided at the bottom of the electrolytic cell. It was used. While pouring the electrolytic replenisher into the electrolytic cell, the composition of the electrolytic solution was adjusted to 40 g / L of manganese and 75 g / L of sulfuric acid at the time of electrolysis, and the temperature of the electrolytic bath was maintained at 90 ° C. and the current density was 35 A. / M ² for 20 days.
[0047]
After the completion of the electrolysis, the anode plate on which the electrolytic manganese dioxide was electrodeposited was taken out and subjected to post-treatment according to a conventional method to obtain the electrolytic manganese dioxide of Example 1.
[0048]
(Example 2)
An electrolytic manganese dioxide of Example 2 was obtained in the same manner as in Example 1 except that the temperature of the electrolytic bath was lowered to 85 ° C.
[0049]
(Example 3)
An electrolytic manganese dioxide of Example 3 was obtained in the same manner as in Example 1 except that the temperature of the electrolytic bath was increased to 95 ° C.
[0050]
(Example 4)
An electrolytic manganese dioxide of Example 4 was obtained in the same manner as in Example 1 except that the current density was reduced to 20 A / m ² .
[0051]
(Example 5)
An electrolytic manganese dioxide of Example 5 was obtained in the same manner as in Example 1 except that the current density was increased to 50 A / m ² .
[0052]
(Example 6)
An electrolytic manganese dioxide of Example 6 was obtained in the same manner as in Example 1 except that the concentration of sulfuric acid in the electrolytic solution was reduced to 50 g / L.
[0053]
(Example 7)
An electrolytic manganese dioxide of Example 7 was obtained in the same manner as in Example 1, except that the concentration of sulfuric acid in the electrolytic solution was increased to 100 g / L.
[0054]
(Example 8)
An electrolytic manganese dioxide of Example 8 was obtained in the same manner as in Example 1 except that the temperature of the electrolytic bath was lowered to 80 ° C.
[0055]
(Example 9)
An electrolytic manganese dioxide of Example 9 was obtained in the same manner as in Example 1 except that the temperature of the electrolytic bath was increased to 98 ° C.
[0056]
(Example 10)
An electrolytic manganese dioxide of Example 10 was obtained in the same manner as in Example 1 except that the current density was reduced to 15 A / m ² .
[0057]
(Comparative Example 1)
An electrolytic manganese dioxide of Comparative Example 1 was obtained in the same manner as in Example 1 except that the current density was increased to 55 A / m ² .
[0058]
(Comparative Example 2)
An electrolytic manganese dioxide of Comparative Example 2 was obtained in the same manner as in Example 1 except that the sulfuric acid concentration of the electrolytic solution was reduced to 45 g / L.
[0059]
(Comparative Example 3)
An electrolytic manganese dioxide of Comparative Example 3 was obtained in the same manner as in Example 1 except that the sulfuric acid concentration of the electrolytic solution was increased to 105 g / L.
[0060]
(Test Example 1)
The sulfate group, the potential, and the specific surface area of the electrolytic manganese dioxide obtained in Examples 1 to 10 and Comparative Examples 1 to 3 were measured. Table 1 shows the measurement results. The sulfate groups in the electrolytic manganese dioxide were measured by a normal ICP emission spectroscopy. The potential was measured by immersing electrolytic manganese dioxide pressed into a nickel can in a potassium hydroxide aqueous solution for 24 hours, and then measuring the potential difference from the mercury / mercury oxide electrode. The measurement of the specific surface area was performed by heating the electrolytic manganese dioxide at 250 ° C. for 20 minutes in a nitrogen stream to remove water in the pores, and then performing the BET one-point method.
[0061]
[Table 1]

[0062]
As shown in Table 1, the electrolytic manganese dioxides of Examples 1 to 10 had a high potential of 270 to 320 mV because the sulfate group was 1.3 to 1.6% by weight. In particular, the electrolytic manganese dioxides of Examples 1 to 7 had a specific surface area of 40 to 65 m ² / g.
[0063]
In addition, from the results of Examples 1 to 7, it was found that if the electrolyte was manufactured under electrolysis conditions of an electrolysis temperature of 85 to 95 ° C., a current density of 20 to 50 A / m ² , and a sulfuric acid concentration of 50 to 100 g / L, the sulfate content was 1.3 to 1.3 g. It turned out to be an electrolytic manganese dioxide having 1.6% by weight, a potential of 270 to 320 mV, and a specific surface area of 40 to 65 m ² / g.
[0064]
(Examples 1A to 10A)
LR6 (AA) type alkaline manganese batteries were produced using the electrolytic manganese dioxide of Examples 1 to 10 as a positive electrode active material. Here, as the electrolytic solution of the battery, a solution obtained by adding about 1.0% of carbomethoxycellulose and sodium polyacrylate as gelling agents to a solution obtained by saturating zinc oxide with a 40% aqueous potassium hydroxide solution is used. Was. In addition, 3.0 g of zinc powder was used as the negative electrode active material, and a mixture of the negative electrode active material and 1.5 g of the above-described electrolytic solution to form a gel was directly used as a negative electrode material. FIG. 1 shows a longitudinal sectional view of the alkaline manganese battery thus manufactured.
[0065]
As shown in FIG. 1, the alkaline manganese battery according to the present invention is provided with a positive electrode active material 2 composed of electrolytic manganese dioxide disposed inside a positive electrode can 1 and a separator 3 disposed inside the positive electrode active material 2 with a separator 3 interposed therebetween. And a negative electrode material 4 made of gelled zinc powder. A negative electrode current collector 5 is inserted into the negative electrode material 4, and the negative electrode current collector 5 penetrates a sealing body 6 closing the lower part of the positive electrode can 1, and a negative electrode bottom plate 7 provided below the sealing body 6. Are joined. On the other hand, a cap 8 serving as a positive electrode terminal is provided above the positive electrode can 1. Insulating

rings

9 and 10 sandwiching the cap 8 and the negative electrode bottom plate 7 from above and below are provided. The cap 8 and the negative electrode bottom plate 7 are fixed via the insulating

rings

9 and 10 and heat shrink so as to cover the outer periphery of the positive electrode can 1. A conductive resin tube 11 and an outer can 12 covering the same are provided.
[0066]
(Comparative Examples 1A to 3A)
Alkaline manganese batteries were produced in the same manner as in Examples 1A to 10A, using the electrolytic manganese dioxides of Comparative Examples 1 to 3 as a positive electrode active material.
[0067]
(Test Example 2)
The alkaline manganese batteries of Examples 1A to 10A and Comparative Examples 1A to 3A were discharged at 20 ° C. and a discharge current of 10 mA (low rate), and the discharge time until a cut voltage (final voltage) of 0.9 V was measured. The low rate characteristic was evaluated by setting the value of Example 9A to 100%.
[0068]
(Test Example 3)
The alkaline manganese batteries of Examples 1A to 10A and Comparative Examples 1A to 3A were discharged at a discharge current of 1000 mA (high rate) at 20 ° C., and the discharge time until a cut voltage (final voltage) of 0.9 V was measured. The high-rate characteristic was evaluated by setting the value of Example 9A to 100%.
[0069]
(Test Example 4)
Regarding the alkaline manganese batteries of Examples 1A to 10A and Comparative Examples 1A to 3A, pulse repetitive discharge of ON for 10 seconds and OFF for 50 seconds was performed at 20 ° C. and a discharge current of 1000 mA (high rate), and the cut voltage (final voltage) was 0.9 V. The number of pulses up to was measured. The high-rate pulse characteristic was evaluated by setting the value of Example 9A to 100%. Table 2 shows the measurement results of Test Examples 2 to 4. In addition, the sulfate content and the specific surface area of the electrolytic manganese dioxide shown in Table 1 are also described.
[0070]
[Table 2]

[0071]
As shown in Table 2, in Examples 1A to 10A in which electrolytic manganese dioxide having a sulfate group content of 1.3 to 1.6% by weight was used as the positive electrode active material, the results were almost as compared with Comparative Examples 1A to 3A. Excellent high rate characteristics and high rate pulse characteristics were exhibited. In particular, in Examples 1A to 7A in which the specific surface area of the electrolytic manganese dioxide is 40 to 65 m ² / g, excellent high rate characteristics and high rate pulse characteristics are exhibited, and the specific surface area is out of the range of 40 to 65 m ² / g. The results were good as compared with Examples 8A to 10A.
[0072]
As shown in Tables 1 and 2, Examples 1A to 3A in which electrolysis was performed at an electrolysis temperature of 85 to 95 ° C. exhibited a high rate characteristic of an alkali manganese battery of 5 to 10% as compared with Example 9A in which electrolysis was performed at 98 ° C. The high-rate pulse characteristics were improved by 10 to 20%. In addition, in Example 8A in which electrolysis was performed at 80 ° C., the low rate characteristics were significantly reduced as compared with Examples 1A to 3A and Example 9A.
[0073]
In Example 1A, and electrolysis was performed at a current density of 20 to 50 A / ^{m 2,} 4A and 5A are high rate pulse characteristics as compared with Example 10A, and electrolysis was performed at 15A / ^{m 2} was improved from 10 to 18%. In addition, Comparative Example 1A electrolyzed at 55 A / m ² was equal to or less than all the battery characteristics as compared with Examples 1A, 4A, 5A and 10A.
[0074]
Further, in Examples 1A, 6A and 7A electrolyzed at a sulfuric acid concentration of 50 to 100 g / L, the high-rate pulse characteristics were improved by 15% as compared with Comparative Example 2A electrolyzed at 45 g / L. In Comparative Example 3A electrolyzed at 105 g / L, all battery characteristics were inferior to Examples 1A, 6A and 7A, and Comparative Example 2A.
[0075]
Therefore, as in Examples 1A to 7A, the sulfate group content of 1. obtained by manufacturing under electrolysis conditions of an electrolysis temperature of 85 to 95 ° C., a current density of 20 to 50 A / m ² , and a sulfuric acid concentration of 50 to 100 g / L. When electrolytic manganese dioxide having a density of ^{3 to} 1.6% by weight, a potential of 270 to 320 mV, and a specific surface area of 40 to 65 m ² / g is used as a positive electrode active material, an alkaline manganese battery having excellent high-rate characteristics and high-rate pulse characteristics is obtained. Was.
[0076]
【The invention's effect】
As described above, according to the present invention, since the electrolytic manganese dioxide contains 1.3 to 1.6% by weight of a sulfate group, it can be used as a positive electrode active material for a battery with a high potential, and further, the specific surface area can be reduced. When it is as high as 40 to 65 m ² / g, a high-performance positive electrode active material for a battery can be provided. Further, by performing electrolysis under the electrolysis conditions of an electrolysis temperature of 85 to 95 ° C., a current density of 20 to 50 A / m ² , and a sulfuric acid concentration of 50 to 100 g / L, 1.3 to 1.6% by weight of a sulfate group and a potential of 270 to 270. Electrolytic manganese dioxide having a specific surface area of 320 mV and a specific surface area of 40 to 65 m ² / g can be obtained. Furthermore, when this electrolytic manganese dioxide is used as a positive electrode active material of a battery, there is an effect that a battery excellent in high rate characteristics, high rate pulse characteristics, and the like can be obtained.
[Brief description of the drawings]
FIG. 1 is a sectional view of an alkaline manganese battery according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Positive electrode can 2 Positive electrode active material 3 Separator 4 Negative electrode material 5 Negative current collector 6 Sealing body 7 Negative bottom plate 8

Cap

9, 10 Insulating ring 11 Heat-shrinkable resin tube 12 Outer can

Claims

A positive electrode active material for a battery comprising electrolytic manganese dioxide, wherein the electrolytic manganese dioxide contains 1.3 to 1.6% by weight of a sulfate group.

In claim 1, the positive electrode active material for a battery having a specific surface area of the electrolytic manganese dioxide is characterized in that it is a 40~65m 2 / ^g.

The positive electrode active material for a battery according to claim 1 or 2, wherein the potential of the electrolytic manganese dioxide is 270 to 320 mV.

The electrolytic manganese dioxide according to any one of claims 1 to 3, wherein manganese sulfate and a sulfuric acid solution are used as an electrolytic solution, an electrolytic temperature of 85 to 95 ° C, an electrolytic current density of 20 to 50 A / m ^{2, and} an electrolytic current density of 50 to 100 g / L. A positive electrode active material for a battery, obtained by electrolysis at a sulfuric acid concentration.

In a method for producing electrolytic manganese dioxide by performing electrolysis using manganese sulfate and a sulfuric acid solution as an electrolytic solution, the electrolytic process is performed at an electrolytic temperature of 85 to 95 ° C., an electrolytic current density of 20 to 50 A / m ² , and a sulfuric acid concentration of 50 to 100 g / L. A method for producing electrolytic manganese dioxide.

The method for producing electrolytic manganese dioxide according to claim 5, wherein the content of sulfate in the electrolytic manganese dioxide is 1.3 to 1.6% by weight.

According to claim 5 or 6, method of manufacturing an electrolytic manganese dioxide having a specific surface area of the electrolytic manganese dioxide is characterized in that it is a 40~65m 2 / ^g.

The method for producing electrolytic manganese dioxide according to any one of claims 5 to 7, wherein the potential of the electrolytic manganese dioxide is 270 to 320 mV.

A battery comprising the positive electrode active material for a battery according to claim 1.