JP3368029B2 - Rechargeable battery - Google Patents
Rechargeable batteryInfo
- Publication number
- JP3368029B2 JP3368029B2 JP34030593A JP34030593A JP3368029B2 JP 3368029 B2 JP3368029 B2 JP 3368029B2 JP 34030593 A JP34030593 A JP 34030593A JP 34030593 A JP34030593 A JP 34030593A JP 3368029 B2 JP3368029 B2 JP 3368029B2
- Authority
- JP
- Japan
- Prior art keywords
- positive electrode
- battery
- lithium
- secondary battery
- prepared
- 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.)
- Expired - Lifetime
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
Landscapes
- Secondary Cells (AREA)
- Battery Electrode And Active Subsutance (AREA)
Description
【発明の詳細な説明】
【０００１】
【産業上の利用分野】この発明は、非水電解液二次電池
の性能改善に関するものである。
【０００２】
【従来の技術】電子機器の小型化、軽量化が進められる
中、その電源として高エネルギー密度の二次電池の要望
がさらに強まっている。その要望に答えるため、非水電
解液二次電池が注目され、その実用化が試みられて来
た。特に負極にリチウム金属を使用する、いわゆるリチ
ウム二次電池は最も可能性が大きいと思われたが、金属
リチウム負極は充放電の繰り返しによりパウダー化して
著しくその性能が劣化したり、また金属リチウムがデン
ドライトに析出し内部ショートを引起したりするため、
実用的なサイクル寿命に問題があり、今だ実用化は難し
い。そこで最近ではカーボンへのリチウムイオンの出入
りを利用するカーボン電極を負極とする非水電解液二次
電池が開発中である。この電池は本発明者等によって、
リチウムイオン二次電池と名付けて１９９０年に始めて
世の中に紹介されたもので（雑誌Ｐｒｏｇｒｅｓｓ Ｉ
ｎ Ｂａｔｔｅｒｉｅｓ ＆ ＳｏｌａｒＣｅｌｌｓ，
Ｖｏｌ．９，１９９０，ｐ２０９）、現在では電池業
界、学会においても次世代の二次電池“リチウムイオン
二次電池”と呼ばれるほどに認識され、その実用化に拍
車がかかっている。代表的には正極材料にリチウム含有
複合酸化物（例えばＬｉＭｎ２Ｏ４、ＬｉＣｏＯ２、
ＬｉＮｉＯ２等）を用い、負極にはコークスやグラファ
イト等の炭素質材料が用いられる。実際、正極にＬｉＣ
ｏＯ２を使用し、負極には特殊な炭素材料（ある程度の
乱層構造を有した擬黒鉛材料）を使用して、２００Ｗｈ
／ｌ程のエネルギー密度を持つリチウムイオン二次電池
が既に少量実用されている。既存のニッケルカドミウム
電池のエネルギー密度は１００〜１５０Ｗｈ／ｌであ
り、リチウムイオン二次電池のエネルギー密度は既存の
電池のそれをはるかに上回るものである。しかし大きな
欠点としてはかなり原材料費が高いことである。安価な
リチウムイオン二次電池を考えるうえで、資源的な理由
からコバルトの価格低下は将来においても望めない。し
たがって、安価な材料という点ではリチウムマンガン複
合酸化物（ＬｉＭｎ２Ｏ４、ＬｉＭｎＯ２等）がリチウ
ムイオン二次電池の正極材料としては極めて魅力的であ
る。さらにリチウムイオン二次電池のもう一つの欠点
は、充放電サイクルに伴う容量の劣化が大きいことであ
る。しかも正極材料としてリチウムマンガン複合酸化物
を使用したものではその劣化は著しく大きい。カーボン
負極は、充電においては電極中のカーボンへリチウムイ
オンがドープされ、放電ではそのカーボンからリチウム
イオンが脱ドープされるだけで、カーボン自身は充放電
に際して大きな結晶構造の変化を伴わないので、極めて
安定した充放電特性を示し、充放電に伴う特性劣化が少
なく、具体的には１０００回以上の充放電の繰り返しも
可能である。しかし、実際のリチウムイオン二次電池の
サイクルに伴う容量の劣化は、正極の特性劣化により支
配され、充分満足なレベルとは言えない。
【０００３】
【発明が解決しようとする課題】本発明はリチウム含有
複合酸化物を主たる正極活物質材料とする非水電解液二
次電池のサイクル特性の改善に関するものである。
【０００４】
【課題を解決するための手段】課題解決の手段は、正極
中に正極活物質であるリチウム含有複合酸化物に混じて
ＢａＯ、ＭｇＯ、ＣａＯから選ばれる１種以上の酸化物
を添加してなるものである。
【０００５】
【作用】正極にリチウム含有複合酸化物（ＬｉＭｎ２Ｏ
４、ＬｉＭｎＯ２，ＬｉＣｏＯ２、ＬｉＮｉＯ２等）を
使用すると、充電状態ではいずれの複合酸化物もリチウ
ムイオンが脱ドープされた状態となり、不安定になる。
従って充放電を何回も繰り返していくうち、正極活物質
が徐々に変化し次第に充放電機能を失っていくため、充
放電サイクルに伴って容量が劣化していく。そこで本発
明者は充電状態にある正極活物質の安定化を目的に鋭意
研究した結果、ＢａＯ、ＭｇＯ、ＣａＯから選ばれる１
種以上の酸化物を正極活物質に混じて正極中に添加する
ことにより、充電状態の正極活物質の安定性が増し、充
放電サイクルに伴う容量劣化がきわめて小さい非水電解
液二次電池となることを見いだしたものである。
【０００６】
【実施例】以下、実施例により本発明をさらに詳しく説
明する。
【０００７】実施例１
図１を参照しながら本発明を具体的な円筒型電池につい
て説明する。図１は本実施例の電池の全体構造を示すも
のである。本発明を実施するための発電要素である電池
素子は次のようにして用意した。２８００℃で熱処理を
施したメソカーボンマイクロビーズ（ｄ００２＝３．３
７Å）の９０重量部に結着剤としてポリフッ化ビニリデ
ン（ＰＶＤＦ）１０重量部を加え、溶剤であるＮ−メチ
ル−２−ピロリドンと湿式混合してスラリー（ペースト
状）にした。そしてこのスラリーを集電体となる厚さ
０．０１ｍｍの銅箔の両面に均一に塗布し、乾燥後ロー
ラープレス機で加圧成型して帯状の負極（１）を作成し
た。続いて正極は次のようにして用意した。市販の二酸
化マンガン（ＭｎＯ２）と炭酸リチウム（Ｌｉ２Ｃ
Ｏ３）をＬｉとＭｎの原子比が１：２の組成比になるよ
うに混合し、これを空気中８００℃で２０時間焼成して
ＬｉＭｎ２Ｏ４を調整した。このＬｉＭｎ２Ｏ４の８７
重量部にＢａＯ２重量部、グラファイトを８重量部を加
えてよく混合し、さらに結合剤としてポリフッ化ビニリ
デン３重量部と溶剤であるＮ−メチル−２−ピロリドン
を加えて湿式混合してスラリー（ペースト状）にする。
このスラリーを正極集電体となる厚さ０．０２ｍｍのア
ルミニウム箔の両面に均一に塗布し、乾燥後ローラープ
レス機で加圧成型して帯状の正極（２）を作成した。こ
うして作成した負極（１）と正極（２）はその間に多孔
質ポリプロピレン製セパレータ（３）を挟んでロール状
に巻き上げて、平均外径１５．７ｍｍの巻回体として電
池素子を作成した。次にニッケルメッキを施した鉄製の
電池缶（４）の底部に絶縁板（５）を設置し、上記電池
素子を収納する。電池素子より取り出した負極リード
（６）を上記電池缶の底に溶接し、電池缶の中に１モル
／リットルのＬｉＰＦ６を溶解したエチレンカーボネイ
ト（ＥＣ）とジエチルカーボネート（ＤＥＣ）の混合溶
液を電解液として注入する。その後、電池素子の上部に
も絶縁板（５）を設置し、ガスケット（７）を嵌め、防
爆弁（８）を図１に示すように電池内部に設置する。電
池素子より取り出した正極リード（９）はこの防爆弁に
電解液を注入する前に溶接しておく。防爆弁の上には正
極外部端子となる閉塞蓋体（１０）をドーナツ型ＰＴＣ
スイッチ（１１）を挟んで重ね、電池缶の縁をかしめ
て、図１に示す電池構造で外径１６．５ｍｍ、高さ６５
ｍｍの電池（Ａ）を完成した。
【０００８】比較例
使用する正極を従来法により作成し、他は全て実施例１
と同じにして従来法による電池（Ｘ）を作成した。従来
法による正極は次のようにして用意される。実施例１で
調整した紛末状ＬｉＭｎ２Ｏ４を８９重量部にグラファ
イトを８重量部混合し、さらに結合剤としてポリフッ化
ビニリデン３重量部と溶剤であるＮ−メチル−２−ピロ
リドンを加えて湿式混合してスラリー（ペースト状）に
する。次に、このスラリーを正極集電体となる厚さ０．
０２ｍｍのアルミニウム箔の両面に均一に塗布し、乾燥
後ローラープレス機で加圧成型して帯状の正極（２ｃ）
を作成した。後は、この正極（２ｃ）と実施例１で作成
したものと同じ負極（１）をその間に多孔質ポリプロピ
レン製セパレータ（３）を挟んでロール状に巻き上げ
て、平均外径１５．７ｍｍの電池素子を作成し、全くそ
の後は実施例１と同じにして電池（Ｘ）を作成した。
【０００９】実施例２
実施例１で調整したのＬｉＭｎ２Ｏ４の８７重量部にＭ
ｇＯの２重量部、グラファイト８重量部を混合し、さら
に結合剤としてポリフッ化ビニリデン３重量部と溶剤で
あるＮ−メチル−２−ピロリドンを加えて湿式混合して
スラリー（ペースト状）にする。続いてこのスラリーを
正極集電体となる厚さ０．０２ｍｍのアルミニウム箔の
両面に均一に塗布し、乾燥後ローラープレス機で加圧成
型して帯状の正極（２ｂ）を作成した。後は、この正極
（２ｂ）と実施例１で作成したものと同じ負極（１）を
その間に多孔質ポリプロピレン製セパレータ（３）を挟
んでロール状に巻き上げて、平均外径１５．７ｍｍの電
池素子を作成し、全くその後も実施例１と同じにして電
池（Ｂ）を作成した。
【００１０】テスト結果
こうして実施例１、２及び比較例で作成した電池は、い
ずれも電池内部の安定化を目的に常温で１２時間のエー
ジング期間を経過させた後、充電上限電圧を４．２Ｖに
設定し、常温で８時間の充電を行い、放電は同じく常温
で全ての電池について８００ｍＡの定電流放電にて終止
電圧３．０Ｖまで行い、それぞれの電池の初期放電容量
を求めた。その後各電池は４０℃の高温槽中で充放電サ
イクル試験を行った。充電電流は４００ｍＡで、充電上
限電圧は４．２Ｖに設定して４時間の充電を行い、放電
は８００ｍＡの定電流放電にて終止電圧３．０Ｖまで行
って充放電を繰り返し、４０サイクルおよび１００サイ
クル時点での各電池の８００ｍＡ放電での放電容量を求
めた。その結果は表１にまとめた通りである。表１に示
すとおり、本発明による電池（Ａ）および（Ｂ）は充放
電を繰り返しても、その容量低下が少なく、４０サイク
ル、１００サイクルの各時点では比較例による従来法の
電池（Ｘ）との容量差はかなり大きくなる。本実施例で
作成したリチウムイオン二次電池のように、正極活物質
にリチウムマンガン複合酸化物（ＬｉＭｎ２Ｏ４）を使
用する場合には、従来法で作成した電池（Ｘ）に見られ
るように、特に高温における充放電サイクルでは容量が
かなり急激に減っていく。１００サイクル時点ではすで
に初期容量の半分程の容量となってしまう。
しかし表１に示すように、正極にＢａＯおよびＭｇＯを
添加混合した本発明による電池（Ａ）および（Ｂ）で
は、正極活物質としてリチウムマンガン複合酸化物（Ｌ
ｉＭｎ２Ｏ４）を使用した電池においても、極めて劣化
度合いは少なくなり、１００サイクル時点でも８８０〜
８８５ｍＡｈの放電容量が得られる。これはエネルギー
密度にすれば約２３０Ｗｈ／ｌであり、現在商品化され
ているコバルトを使用したリチウムイオン二次電池の初
期エネルギー密度をも上回るものである。また内部抵抗
変化においては、１００サイクル終了時点で、従来法に
よる電池は（Ｘ）数十ミリオームの変化が見られるのに
対し、本発明による電池の内部抵抗変化は（Ａ）、
（Ｂ）共に数ミリオームで非常に少ないことが確認され
た。以上のように本発明はリチウムイオン二次電池の最
も大きな欠点であったサイクルに伴う容量劣化を大幅に
改善することが出来る。なお上述の実施例では本発明の
効果がもっとも顕著に表れる例として、正極活物質とし
てＬｉＭｎ２Ｏ４を使用した場合について説明したが、
ＬｉＣｏＯ２やＬｉＮｉＯ２等他のリチウム含有複合酸
化物を正極活物質として使用する非水電解液二次電池に
おいても本発明は改善効果を現すものである。また上述
の実施例では正極活物質にＢａＯおよびＭｇＯを添加し
て正極を作成した場合について説明したが、その他にも
ＣａＯが同様な添加効果を示す。
【００１１】
【発明の効果】以上述べたように本発明にあっては、リ
チウム含有複合酸化物（例えばＬｉＭｎ２Ｏ４、ＬｉＣ
ｏＯ２、ＬｉＮｉＯ２等）に混合してＢａＯ、ＭｇＯ、
ＣａＯから選ばれる１種以上の酸化物を添加してリチウ
ムイオン二次電池の正極を作成することにより、リチウ
ムイオン二次電池のこれまでの大きな欠点である充放電
サイクルに伴う容量劣化を大幅に改善できる。特に、リ
チウムマンガン複合酸化物を正極活物質として用いるリ
チウムイオン二次電池においては、改善効果が著しく、
既存の二次電池に充分に代わりうる、高容量、長寿命で
且つ安価なリチウムイオン二次電池を提供できるように
なり、その工業的価値は大である。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improving the performance of a non-aqueous electrolyte secondary battery. 2. Description of the Related Art As electronic devices have been reduced in size and weight, there has been a growing demand for high energy density secondary batteries as power sources. In order to respond to such demands, attention has been paid to non-aqueous electrolyte secondary batteries, and their practical use has been attempted. In particular, the so-called lithium secondary battery, which uses lithium metal for the negative electrode, seems to have the highest potential.However, the performance of the lithium metal negative electrode is remarkably deteriorated due to powdering due to repeated charging and discharging, To precipitate on dendrite and cause internal short circuit,
There is a problem in the practical cycle life, and practical use is still difficult. Therefore, recently, a non-aqueous electrolyte secondary battery using a carbon electrode, which utilizes the inflow and outflow of lithium ions to and from carbon, as a negative electrode is being developed. This battery is provided by the present inventors.
It was first introduced in the world in 1990 under the name of lithium-ion secondary battery (Progress I Magazine)
n Batteries & SolarCells,
Vol. 9, 1990, p. 209), which is now recognized by the battery industry and academic societies as being called the next-generation secondary battery “lithium ion secondary battery”, and its practical use is being spurred. Typically, a lithium-containing composite oxide (eg, LiMn 2 O 4 , LiCoO 2 ,
LiNiO 2 or the like, and a carbonaceous material such as coke or graphite is used for the negative electrode. In fact, LiC
using oO 2, with a special carbon material for the negative electrode (擬黒lead material having a certain degree of turbostratic), 200Wh
Lithium ion secondary batteries having an energy density of about / l have already been put into practical use. The energy density of the existing nickel cadmium battery is 100 to 150 Wh / l, and the energy density of the lithium ion secondary battery is far higher than that of the existing battery. However, a major disadvantage is that the cost of raw materials is quite high. In considering an inexpensive lithium-ion secondary battery, a price reduction of cobalt cannot be expected in the future due to resource reasons. Therefore, in terms of inexpensive materials, lithium manganese composite oxides (LiMn 2 O 4 , LiMnO 2, etc.) are extremely attractive as positive electrode materials for lithium ion secondary batteries. Further, another disadvantage of the lithium ion secondary battery is that the capacity is greatly deteriorated due to charge / discharge cycles. Moreover, the deterioration using lithium manganese composite oxide as the positive electrode material is remarkably large. The carbon negative electrode is extremely charged because lithium ions are doped into the carbon in the electrode during charging and lithium ions are undoped from the carbon during discharging, and the carbon itself does not involve a large change in crystal structure during charging and discharging. Stable charge-discharge characteristics are exhibited, and characteristic deterioration due to charge-discharge is small. Specifically, charge and discharge can be repeated 1000 times or more. However, the deterioration of the capacity due to the actual cycle of the lithium ion secondary battery is dominated by the deterioration of the characteristics of the positive electrode, and cannot be said to be a sufficiently satisfactory level. [0003] The present invention relates to an improvement in cycle characteristics of a non-aqueous electrolyte secondary battery using a lithium-containing composite oxide as a main positive electrode active material. Means for solving the problem is to add one or more oxides selected from BaO, MgO and CaO into the positive electrode in addition to the lithium-containing composite oxide as the positive electrode active material. It is made. The lithium-containing composite oxide (LiMn 2 O) is used for the positive electrode.
4 , LiMnO 2 , LiCoO 2 , LiNiO 2, etc.), any composite oxide becomes undoped with lithium ions in a charged state and becomes unstable.
Accordingly, as the charge / discharge is repeated many times, the positive electrode active material gradually changes and gradually loses the charge / discharge function, so that the capacity deteriorates with the charge / discharge cycle. Thus, the present inventors have conducted intensive studies with the aim of stabilizing the positive electrode active material in a charged state, and as a result, have found that 1
By adding more than one kind of oxide to the positive electrode active material and adding it to the positive electrode, the stability of the positive electrode active material in the charged state is increased, and the capacity deterioration due to charge / discharge cycles is extremely small. It has been found to be. Hereinafter, the present invention will be described in more detail by way of examples. EXAMPLE 1 The present invention will be described with reference to FIG. 1 for a specific cylindrical battery. FIG. 1 shows the overall structure of the battery of this embodiment. A battery element as a power generating element for carrying out the present invention was prepared as follows. Mesocarbon microbeads heat treated at 2800 ° C. (d002 = 3.3
To 90 parts by weight of 7)), 10 parts by weight of polyvinylidene fluoride (PVDF) was added as a binder, and the mixture was wet-mixed with N-methyl-2-pyrrolidone as a solvent to form a slurry (paste). Then, this slurry was uniformly applied to both sides of a copper foil having a thickness of 0.01 mm as a current collector, dried, and then pressure-molded with a roller press to form a strip-shaped negative electrode (1). Subsequently, the positive electrode was prepared as follows. Commercially available manganese dioxide (MnO 2 ) and lithium carbonate (Li 2 C)
O 3 ) was mixed so that the atomic ratio of Li and Mn was 1: 2, and the mixture was fired in air at 800 ° C. for 20 hours to prepare LiMn 2 O 4 . 87 of this LiMn 2 O 4
2 parts by weight of BaO and 8 parts by weight of graphite are added to parts by weight, and 3 parts by weight of polyvinylidene fluoride as a binder and N-methyl-2-pyrrolidone as a solvent are added and wet-mixed to obtain a slurry (paste). Shape).
This slurry was uniformly applied to both surfaces of a 0.02 mm-thick aluminum foil serving as a positive electrode current collector, dried, and pressure-formed with a roller press to form a belt-shaped positive electrode (2). The negative electrode (1) and the positive electrode (2) thus prepared were wound up in a roll shape with a porous polypropylene separator (3) interposed therebetween to prepare a battery element as a wound body having an average outer diameter of 15.7 mm. Next, an insulating plate (5) is placed on the bottom of the nickel-plated iron battery can (4) to house the battery element. The negative electrode lead (6) taken out from the battery element was welded to the bottom of the battery can, and a mixed solution of ethylene carbonate (EC) and diethyl carbonate (DEC) in which 1 mol / liter of LiPF 6 was dissolved in the battery can. Inject as electrolyte. Thereafter, an insulating plate (5) is also placed on the upper part of the battery element, a gasket (7) is fitted, and an explosion-proof valve (8) is placed inside the battery as shown in FIG. The positive electrode lead (9) taken out from the battery element is welded before injecting the electrolytic solution into the explosion-proof valve. On top of the explosion-proof valve, a donut-shaped PTC is used to close the closing lid (10), which is the positive electrode external terminal.
The switch (11) is sandwiched between them, and the edge of the battery can is swaged to form the battery structure shown in FIG.
mm battery (A) was completed. Comparative Example A positive electrode to be used was prepared by a conventional method, and all others were the same as in Example 1.
A battery (X) according to a conventional method was prepared in the same manner as described above. A positive electrode according to a conventional method is prepared as follows. 89 parts by weight of the powdery LiMn 2 O 4 prepared in Example 1 was mixed with 8 parts by weight of graphite, and 3 parts by weight of polyvinylidene fluoride as a binder and N-methyl-2-pyrrolidone as a solvent were added. Wet-mix to form slurry (paste). Next, this slurry was used to form a positive electrode current collector having a thickness of 0.1 mm.
Uniformly coated on both sides of an aluminum foil of 02 mm, dried and pressure-formed with a roller press to form a belt-shaped positive electrode (2c)
It was created. Thereafter, the positive electrode (2c) and the same negative electrode (1) as that prepared in Example 1 were wound into a roll with a porous polypropylene separator (3) interposed therebetween, and a battery having an average outer diameter of 15.7 mm was obtained. An element was prepared, and thereafter, a battery (X) was prepared in the same manner as in Example 1. Example 2 Mn was added to 87 parts by weight of LiMn 2 O 4 prepared in Example 1.
2 parts by weight of gO and 8 parts by weight of graphite are mixed, and 3 parts by weight of polyvinylidene fluoride as a binder and N-methyl-2-pyrrolidone as a solvent are added and wet-mixed to form a slurry (paste). Subsequently, this slurry was uniformly applied to both surfaces of a 0.02 mm-thick aluminum foil serving as a positive electrode current collector, dried, and pressure-formed with a roller press to form a belt-shaped positive electrode (2b). Thereafter, the positive electrode (2b) and the same negative electrode (1) as that prepared in Example 1 were wound up in a roll with a porous polypropylene separator (3) interposed therebetween, and a battery having an average outer diameter of 15.7 mm was obtained. A device was prepared, and a battery (B) was prepared exactly as in Example 1 thereafter. Test Results In the batteries prepared in Examples 1 and 2 and Comparative Example, an aging period of 12 hours was passed at room temperature for the purpose of stabilizing the inside of the batteries. The battery was charged at room temperature for 8 hours, and the discharge was performed at the same temperature at a constant current of 800 mA to a final voltage of 3.0 V for all the batteries. The initial discharge capacity of each battery was determined. Thereafter, each battery was subjected to a charge / discharge cycle test in a high-temperature bath at 40 ° C. The charging current was 400 mA, the charging upper limit voltage was set to 4.2 V, and charging was performed for 4 hours. The discharging was performed at a constant current discharge of 800 mA to a final voltage of 3.0 V, and charging and discharging were repeated. The discharge capacity at 800 mA discharge of each battery at the time of the cycle was determined. The results are as summarized in Table 1. As shown in Table 1, the batteries (A) and (B) according to the present invention showed a small decrease in capacity even after repeated charge and discharge, and at each time point of 40 cycles and 100 cycles, the batteries (X) of the conventional method according to the comparative example. And the capacity difference becomes considerably large. When a lithium manganese composite oxide (LiMn 2 O 4 ) is used as the positive electrode active material as in the lithium ion secondary battery prepared in this example, it can be seen in the battery (X) prepared by the conventional method. In particular, in a charge / discharge cycle at a high temperature, the capacity decreases considerably sharply. At the time of 100 cycles, the capacity is already about half of the initial capacity. However, as shown in Table 1, in the batteries (A) and (B) according to the present invention in which BaO and MgO were added and mixed to the positive electrode, a lithium manganese composite oxide (L
Also in the battery using iMn 2 O 4 ), the degree of deterioration is extremely small, and even at the time of 100 cycles, it is 880-800.
A discharge capacity of 885 mAh is obtained. This is approximately 230 Wh / l in terms of energy density, which is even higher than the initial energy density of currently commercialized lithium ion secondary batteries using cobalt. Regarding the internal resistance change, at the end of 100 cycles, the battery according to the conventional method shows a change of (X) several tens of milliohms, while the internal resistance change of the battery according to the present invention is (A)
(B) It was confirmed that both were very small at several milliohms. As described above, the present invention can significantly improve the capacity deterioration due to the cycle, which is the biggest drawback of the lithium ion secondary battery. In the above-described embodiment, the case where LiMn 2 O 4 is used as the positive electrode active material has been described as an example in which the effect of the present invention is most remarkably exhibited.
The present invention also shows an improvement effect in a non-aqueous electrolyte secondary battery using a lithium-containing composite oxide such as LiCoO 2 or LiNiO 2 as a positive electrode active material. Further, in the above-described embodiment, the case where BaO and MgO are added to the positive electrode active material to form the positive electrode has been described. However, CaO exhibits the same addition effect. As described above, in the present invention, a lithium-containing composite oxide (eg, LiMn 2 O 4 , LiC
oO 2 , LiNiO 2 etc.) and mixed with BaO, MgO,
By adding one or more oxides selected from CaO to form a positive electrode of a lithium ion secondary battery, capacity deterioration accompanying a charge / discharge cycle, which has been a major drawback of a lithium ion secondary battery, is greatly reduced. Can be improved. Particularly, in a lithium ion secondary battery using a lithium manganese composite oxide as a positive electrode active material, the improvement effect is remarkable,
A high-capacity, long-life, and inexpensive lithium ion secondary battery that can sufficiently replace an existing secondary battery can be provided, and its industrial value is great.
【図面の簡単な説明】
【図１】実施例および比較例における電池の構造を示し
た模式的断面図
【符号の説明】
１は負極、２は正極、３はセパレータ、４は電池缶、５
は絶縁板、６は負極リード、７はガスケット、８は防爆
弁、９は負極リード、１０は閉塞蓋体である。BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic cross-sectional view showing the structure of a battery in Examples and Comparative Examples [Description of symbols] 1 is a negative electrode, 2 is a positive electrode, 3 is a separator, 4 is a battery can, 5
Denotes an insulating plate, 6 denotes a negative electrode lead, 7 denotes a gasket, 8 denotes an explosion-proof valve, 9 denotes a negative electrode lead, and 10 denotes a closing lid.
Claims (1)
液を有する電池であって、前記正極にはリチウムマンガ
ン複合酸化物ＬｉＭｎ2Ｏ4が活物質として使用される非
水電解液二次電池において、正極中に前記活物質に混じ
てＢａＯ、ＭｇＯ、ＣａＯから選ばれる少なくとも一種
の酸化物を添加してなることを特徴とする非水電解液二
次電池。(57) Claims 1. A battery having a positive electrode, a negative electrode, a separator, and a non-aqueous electrolyte, wherein a lithium manganese composite oxide LiMn 2 O 4 is used as an active material for the positive electrode. A non-aqueous electrolyte secondary battery characterized in that at least one oxide selected from BaO, MgO, and CaO is added to the positive electrode in the positive electrode.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP34030593A JP3368029B2 (en) | 1993-11-26 | 1993-11-26 | Rechargeable battery |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP34030593A JP3368029B2 (en) | 1993-11-26 | 1993-11-26 | Rechargeable battery |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH07153496A JPH07153496A (en) | 1995-06-16 |
| JP3368029B2 true JP3368029B2 (en) | 2003-01-20 |
Family
ID=18335676
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP34030593A Expired - Lifetime JP3368029B2 (en) | 1993-11-26 | 1993-11-26 | Rechargeable battery |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3368029B2 (en) |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| ID20037A (en) * | 1997-03-13 | 1998-09-17 | Matsushita Electric Ind Co Ltd | SECONDARY LITIUM BATTERY |
| JPH11204145A (en) * | 1998-01-20 | 1999-07-30 | Yuasa Corp | Lithium secondary battery |
| JP3244227B2 (en) | 1999-04-26 | 2002-01-07 | 日本電気株式会社 | Non-aqueous electrolyte secondary battery |
| JP4101435B2 (en) | 1999-05-25 | 2008-06-18 | 三星エスディアイ株式会社 | Positive electrode active material composition for lithium secondary battery and method for producing positive electrode using the same |
| KR100371404B1 (en) * | 1999-09-28 | 2003-02-07 | 주식회사 엘지화학 | Non-aqueous electrolyte battery |
| EP1139460B1 (en) | 2000-03-31 | 2012-08-01 | Sony Corporation | Separator, gelated electrolyte, non-aqueous electrolyte, electrode and non-aqueous electrolyte cell employing the same |
| WO2003090295A1 (en) | 2002-04-19 | 2003-10-30 | Bridgestone Corporation | Positive electrode for nonaqueous electrolyte battery, process for producing the same and nonaqueous electrolyte battery |
| KR100893227B1 (en) | 2006-07-28 | 2009-04-16 | 주식회사 엘지화학 | Anode for improving storage performance at a high temperature and lithium secondary battery comprising the same |
| KR101470336B1 (en) * | 2012-04-17 | 2014-12-08 | 주식회사 엘지화학 | Additive for Secondary Battery |
| JP6129993B2 (en) | 2013-02-14 | 2017-05-17 | エルジー・ケム・リミテッド | Positive electrode active material for lithium secondary battery and lithium secondary battery including the same |
-
1993
- 1993-11-26 JP JP34030593A patent/JP3368029B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH07153496A (en) | 1995-06-16 |
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