JPH0554888A - Manufacture of nonaqueous electrolyte secondary electrode - Google Patents
Manufacture of nonaqueous electrolyte secondary electrodeInfo
- Publication number
- JPH0554888A JPH0554888A JP3244508A JP24450891A JPH0554888A JP H0554888 A JPH0554888 A JP H0554888A JP 3244508 A JP3244508 A JP 3244508A JP 24450891 A JP24450891 A JP 24450891A JP H0554888 A JPH0554888 A JP H0554888A
- Authority
- JP
- Japan
- Prior art keywords
- cobalt
- lithium
- battery
- positive electrode
- active material
- 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.)
- Granted
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
Description
【０００１】[0001]
【産業上の利用分野】本発明は、高エネルギー密度化を
目的とする非水電解液二次電池、とくにリチウム二次電
池の正極活物質に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positive electrode active material for a non-aqueous electrolyte secondary battery, especially a lithium secondary battery, for the purpose of increasing energy density.
【０００２】[0002]
【従来の技術】近年、民生用電子機器のポータブル化，
コードレス化が急速に進んでいる。現在、これら電子機
器の駆動用電源としての役割を、ニッケルカドミウム蓄
電池あるいは密閉型小形鉛蓄電池が担っているが、ポー
タブル化，コードレス化が進展し、定着するに従い、駆
動用電源となる二次電池の高エネルギー密度化，小形
化，軽量化の要望が強くなっている。これら要望を実現
するものとして非水電解液二次電池いわゆるリチウム二
次電池が期待されており、盛んに研究開発が行われてき
た。2. Description of the Related Art In recent years, portable electronic devices for consumer use,
Cordless is advancing rapidly. At present, nickel-cadmium storage batteries or sealed small lead-acid batteries play a role as driving power sources for these electronic devices, but as portable and cordless batteries progress and become established, secondary batteries that will become driving power sources There is a strong demand for higher energy density, smaller size, and lighter weight. Non-aqueous electrolyte secondary batteries, so-called lithium secondary batteries, are expected to fulfill these demands, and research and development have been actively conducted.
【０００３】従来、リチウム二次電池の正極活物質とし
て、リチウムに対し２ボルトから３ボルトの放電電圧を
有する二酸化マンガン，二硫化モリブデン，五酸化バナ
ジウムなどが用いられてきた。リチウム金属を負極と
し、これら活物質を用いた正極と有機電解液とで構成し
た電池系が主として開発されてきたが、リチウム金属を
負極に用いた場合、充電時に生成するデンドライト状リ
チウムによる内部短絡が起こるなど、十分な安全性を確
保することが困難であり、実用化への大きな障害となっ
ている。更には、現在の技術では高率充放電ができない
という問題がある。リチウムコバルト複合酸化物（以下
ＬｉＣｏＯ2と記す）は、１９８０年に、水島等によ
り、リチウム二次電池の正極活物質として提案された。
この活物質は、リチウムに対し４ボルト近い放電電圧を
示し容量的にも他の活物質に比べて遜色がないため、高
エネルギー密度を実現する活物質として期待される。し
かし、ＬｉＣｏＯ2は充放電に伴う容量劣化が大きく、
また充電状態で保存した場合は容量が大きく劣化すると
いう現象があり、ＬｉＣｏＯ2を正極活物質に使用した
リチウム二次電池は実用化できていない。一方、ＬｉＣ
ｏＯ2が正極活物質として使用できると、高電圧高容量
のため正極のエネルギー密度が大きくなり、負極にリチ
ウムイオンを吸蔵放出し得る有効な炭素材を選択した場
合、十分なエネルギー密度が確保できた上で、リチウム
金属を負極とした場合に生じた完全性，高率充放電特
性，充放電サイクル特性など、実用化への障害となって
いた課題が解決できる可能性がある。このような背景の
もとに、小形軽量で安全性に優れた高エネルギー密度二
次電池を実用化するため、ＬｉＣｏＯ2を始め、高電圧
高容量を有する正極活物質の研究開発が現在盛んに行わ
れている。Conventionally, manganese dioxide, molybdenum disulfide, vanadium pentoxide, etc., which have a discharge voltage of 2 to 3 V against lithium, have been used as positive electrode active materials for lithium secondary batteries. A battery system has been mainly developed which uses a lithium metal as a negative electrode and a positive electrode using these active materials and an organic electrolyte solution.However, when a lithium metal is used as a negative electrode, an internal short circuit due to dendrite-like lithium generated at the time of charging is made. It is difficult to secure sufficient safety, such as the occurrence of the above, which is a major obstacle to practical use. Further, there is a problem that high-rate charging / discharging cannot be performed with the current technology. A lithium cobalt composite oxide (hereinafter referred to as LiCoO 2 ) was proposed by Mizushima et al. In 1980 as a positive electrode active material for a lithium secondary battery.
This active material exhibits a discharge voltage of about 4 V against lithium and is comparable in capacity to other active materials, and is therefore expected as an active material that achieves high energy density. However, LiCoO 2 has a large capacity deterioration due to charge and discharge,
In addition, there is a phenomenon that the capacity is greatly deteriorated when stored in a charged state, and a lithium secondary battery using LiCoO 2 as a positive electrode active material has not been put into practical use. On the other hand, LiC
When oO 2 can be used as the positive electrode active material, the energy density of the positive electrode becomes large due to the high voltage and high capacity, and when an effective carbon material capable of inserting and extracting lithium ions is selected for the negative electrode, sufficient energy density can be secured. In addition, there is a possibility that problems such as perfection, high-rate charge / discharge characteristics, charge / discharge cycle characteristics, etc., which have been caused when lithium metal is used as the negative electrode, may be the obstacles to practical use. Against this background, research and development of positive electrode active materials with high voltage and high capacity, including LiCoO 2 , are currently being actively conducted in order to put into practical use a high energy density secondary battery that is small, lightweight and excellent in safety. Has been done.
【０００４】[0004]
【発明が解決しようとする課題】通常ＬｉＣｏＯ2は、
リチウム塩とコバルト化合物、例えば炭酸リチウムと炭
酸コバルトを所定量（コバルトに対しリチウムが原子比
で０．９から１．０５までの範囲が一般的）混合し、６
００℃ないし１１００℃までの温度で焼成することによ
って得られる（特開平１−３０４６６４号公報）。従来
ＬｉＣｏＯ2は充放電に伴い容量低下が起こることがわ
かっており、また容量低下の度合にもばらつきがあり、
安定して充放電サイクル特性の良好なものが得られてい
ない。その要因については、集電体からの脱離、活物質
自体の構造変化あるいは結晶格子破壊などが考えられて
きたが、詳しいことはわかっていなかった。Generally, LiCoO 2 is
A lithium salt and a cobalt compound, for example, lithium carbonate and cobalt carbonate, are mixed in a predetermined amount (lithium to cobalt is generally in an atomic ratio of 0.9 to 1.05), and mixed.
It is obtained by firing at a temperature of from 00 ° C to 1100 ° C (JP-A-1-304664). Conventionally, it has been known that the capacity of LiCoO 2 decreases with charge and discharge, and the degree of capacity decrease also varies.
Stable and good charge / discharge cycle characteristics have not been obtained. The cause has been considered to be desorption from the current collector, structural change of the active material itself, or crystal lattice destruction, but details have not been known.
【０００５】本発明者らが充分検討を重ねた結果、Ｌｉ
ＣｏＯ2を正極活物質に使用した電池の充放電に伴う容
量低下は、結晶格子の膨張収縮によるＬｉＣｏＯ2粒子
の割れ、および集電体からの脱離が主な原因であると結
論した。As a result of thorough investigations by the present inventors, Li
It was concluded that the decrease in capacity of the battery using CoO 2 as the positive electrode active material due to charge and discharge was mainly due to cracking of LiCoO 2 particles due to expansion and contraction of the crystal lattice and desorption from the current collector.
【０００６】すなわちＬｉＣｏＯ2の結晶格子は六方晶
であり、充電によってリチウムが結晶中から抜けていく
ため酸素層間の反撥が生じ、六方晶のＣ軸が伸び、単位
結晶体積が大きくなるため正極極板の膨張が生じる。従
って充放電に伴い活物質粒子ひいては正極極板が膨張収
縮を繰り返すため、ＬｉＣｏＯ2の合成が不完全であっ
た場合粒子が割れたり、また、粒径の不揃いの程度が大
のものや粒子形状が不定形のものを結着剤と共に、集電
体上に薄く塗着してシート状正極板とする場合は、活物
質間あるいは集電体との結着力が小さくなり、充放電に
伴い極板中の活物質が緩みついには集電体から活物質が
脱落するため容量低下が起こるものと思われる。That is, the crystal lattice of LiCoO 2 is a hexagonal crystal, and lithium is removed from the crystal by charging, so that repulsion occurs between oxygen layers, the C axis of the hexagonal crystal extends, and the unit crystal volume increases, so that the positive electrode Expansion of the plate occurs. Therefore, as the active material particles, and thus the positive electrode plate, repeatedly expand and contract with charge and discharge, the particles may crack if the synthesis of LiCoO 2 is incomplete, or the particles with a large degree of irregularity in particle size or particle shape. When a sheet-shaped positive electrode plate is formed by thinly coating an amorphous material together with a binder on the current collector, the binding force between the active materials or with the current collector becomes small, and the electrode becomes It is considered that the active material in the plate loosens and eventually the active material falls off from the current collector, resulting in a decrease in capacity.
【０００７】また炭酸リチウムと炭酸コバルトを混合し
６００℃から１１００℃程度の温度で焼成する従来の合
成法で合成したＬｉＣｏＯ2は焼結が進行しやすいた
め、強い圧縮力ないし衝撃力による粉砕が必要となる。
そのため粒径制御が困難であり、粒子形状は機械的な粉
砕工程によるため不定形となる。またいずれも炭酸塩か
らなる出発物質が共に熱分解を起こし大きな体積収縮を
伴いながら反応するため焼成むらも生じやすく合成が完
全には進行しにくいと考えられる。そのことは、生成物
がアルカリを呈することが多く、これは未反応の炭酸リ
チウムが残っていることがうかがえる。これらの要因が
相重なって上述したような過程で充電放サイクル特性に
問題が生じていると考えられる。Further, LiCoO 2 synthesized by a conventional synthesis method in which lithium carbonate and cobalt carbonate are mixed and fired at a temperature of about 600 ° C. to 1100 ° C. is liable to be crushed by a strong compressive force or impact force because the sintering is easy to proceed. Will be needed.
Therefore, it is difficult to control the particle size, and the particle shape becomes indefinite due to the mechanical grinding process. In addition, in both cases, the starting materials made of carbonate both undergo thermal decomposition and react with a large volume shrinkage, so uneven firing is likely to occur, and it is considered that the synthesis does not proceed completely. This means that the product often exhibits alkali, which indicates that unreacted lithium carbonate remains. It is considered that these factors overlap and cause a problem in the charge discharge cycle characteristics in the process as described above.
【０００８】本発明の目的は、上記した従来の正極に関
する問題点の解決を図るものであり、特定の条件で合成
されたリチウムコバルト複合酸化物を正極活物質として
用いることにより、充放電サイクルなどの電池特性の優
れた非水電解液二次電池を提供することである。An object of the present invention is to solve the above-mentioned problems relating to the conventional positive electrode, and by using a lithium cobalt composite oxide synthesized under specific conditions as a positive electrode active material, a charge / discharge cycle, etc. To provide a non-aqueous electrolyte secondary battery having excellent battery characteristics.
【０００９】[0009]
【課題を解決するための手段】この課題を解決するため
本発明は、ＬｉＣｏＯ2の出発原料として、コバルト２
価イオン水溶液とアルカリ溶液を混合して生成する、水
酸基を有するコバルト塩を分離した後、酸化雰囲気下に
おいて１００℃ないし９００℃までの温度で熱処理をし
て得たなどの、ほぼ球状もしくは長円球状で平均粒子径
が１μｍ以下の一次粒子が、複数個連接した凝集塊から
なるコバルト酸化物をコバルト源として合成された、粒
径が均一でかつ細かく粒子形状の揃ったリチウムコバル
ト複合酸化物を正極活物質に用いるものである。SUMMARY OF THE INVENTION The present invention for solving this problem, as a starting material of LiCoO 2, cobalt 2
Almost spherical or oval, such as obtained by mixing a valent ion aqueous solution and an alkaline solution, separating a cobalt salt having a hydroxyl group, and then performing a heat treatment at a temperature of 100 ° C. to 900 ° C. in an oxidizing atmosphere. A lithium-cobalt composite oxide having a uniform particle size and a uniform particle shape, which is synthesized by using a cobalt oxide composed of agglomerates in which a plurality of spherical primary particles having an average particle diameter of 1 μm or less are connected to each other. It is used as a positive electrode active material.
【００１０】すなわちＬｉＣｏＯ2の合成法について検
討した結果、前記のごとく、形状がほぼ球状あるいは長
円球状であり、粒子径が１μｍ以下で粒度がほぼ揃った
コバルト酸化物を出発物質に使用すると、出発物質の粒
径にほぼ比例して均一な粒度のＬｉＣｏＯ2が得られる
ことがわかった。さらにコバルト２価イオン水溶液にア
ルカリ溶液を混合して生成する水酸基を有するコバルト
塩を分離し、酸化雰囲気下で１００℃ないし９００℃以
下の温度で熱処理を加えたコバルト酸化物は一次粒子
が、およそ０．５μｍ以下のもので結晶状態が揃ってお
り、これを出発物質として使用すると、単位粒子径が
０．５μｍから３μｍに粒径が揃いかつ、滑らかで規則
性のある統一された粒子形状を有するＬｉＣｏＯ2が合
成できることを見出し、これを正極活物質として用いる
ことで、前記課題を解決したものである。That is, as a result of examining the synthesis method of LiCoO 2 , as described above, when a cobalt oxide having a substantially spherical or ellipsoidal shape and a particle size of 1 μm or less and a substantially uniform particle size is used as a starting material, It has been found that a uniform particle size of LiCoO 2 is obtained which is approximately proportional to the particle size of the starting material. Further, the cobalt salt having a hydroxyl group produced by mixing an alkaline solution with an aqueous solution of divalent cobalt ions is separated, and subjected to heat treatment at a temperature of 100 ° C. to 900 ° C. in an oxidizing atmosphere. The crystalline state is 0.5 μm or less, and when this is used as a starting material, the unit particle size is 0.5 μm to 3 μm, and a smooth, regular and uniform particle shape is obtained. It was found that LiCoO 2 contained therein could be synthesized, and by using this as a positive electrode active material, the above-mentioned problems were solved.
【００１１】[0011]
【作用】上記した特定の条件で合成されたＬｉＣｏＯ2
を正極活物質として用いると、粒子が細かく、均一かつ
均質であり粒子形状も整っているため、シート状の正極
板として、結着剤と共に金属箔などの集電体上に薄く塗
着，充填した場合、充放電に伴う膨張収縮を繰り返して
も極板の塗着層が綬むことがなく、サイクルに伴う容量
劣化を防ぐことができた。また粒径が均一で細かく粒子
形状も滑らかで規則性があるため、同一体積の極板に充
填できる活物質量を多くすることができ、かつ単位重量
当たりの活物質の利用率を高めることができる。Function: LiCoO 2 synthesized under the above specific conditions
When used as a positive electrode active material, the particles are fine, uniform, and uniform, and the particle shape is well-regulated.Thus, as a sheet-shaped positive electrode plate, it is thinly applied and filled on a current collector such as a metal foil together with a binder. In this case, the coating layer of the electrode plate did not warp even after repeated expansion and contraction due to charge and discharge, and it was possible to prevent capacity deterioration due to cycling. In addition, since the particle size is uniform and fine, and the particle shape is smooth and regular, it is possible to increase the amount of active material that can be packed in the same volume electrode plate and increase the utilization rate of the active material per unit weight. it can.
【００１２】従って、本発明による正極を、適当な負
極、例えば充放電効率の良いカーボンやリチウム金属な
どと組み合わせることによって高電圧，高容量を有し、
充放電サイクル特性に優れた非水電解液二次電池を実現
することができる。Therefore, by combining the positive electrode according to the present invention with a suitable negative electrode, for example, carbon or lithium metal having good charge and discharge efficiency, it has a high voltage and a high capacity.
A non-aqueous electrolyte secondary battery having excellent charge / discharge cycle characteristics can be realized.
【００１３】[0013]
【実施例】以下、実施例により本発明を詳しく述べる。
図１に本実施例で用いた円筒形電池の縦断面図を示す。
図において１は耐有機電解液性のステンレス鋼板を加工
した電池ケース、２は安全弁を設けた封口板、３は絶縁
パッキングを示す。４は極板群であり、正極および負極
がセパレータを介して複数回渦巻き状に巻回されてケー
ス内に収納されている。そして上記正極からは正極リー
ド５が引き出されて封口板２に接続され、負極からは負
極リード６が引き出されて電池ケース１の底部に接続さ
れている。７は絶縁リングで極板群４の上下部にそれぞ
れ設けられている。以下、正極板，負極板，電解液等に
ついて詳しく説明する。EXAMPLES The present invention will be described in detail below with reference to examples.
FIG. 1 shows a vertical cross-sectional view of the cylindrical battery used in this example.
In the figure, 1 is a battery case made by processing an organic electrolytic solution resistant stainless steel plate, 2 is a sealing plate provided with a safety valve, and 3 is an insulating packing. Reference numeral 4 denotes an electrode plate group, in which the positive electrode and the negative electrode are spirally wound a plurality of times with the separator interposed therebetween and are housed in the case. A positive electrode lead 5 is drawn out from the positive electrode and connected to the sealing plate 2, and a negative electrode lead 6 is drawn out from the negative electrode and connected to the bottom of the battery case 1. Insulating rings 7 are provided on the upper and lower portions of the electrode plate group 4, respectively. Hereinafter, the positive electrode plate, the negative electrode plate, the electrolytic solution and the like will be described in detail.
【００１４】負極は、コークスを焼成した炭素材１００
重量部に、フッ素樹脂系結着剤１０重量部を混合し、カ
ルボキシメチルセルロース水溶液に懸濁させてペースト
状にした。そしてこのペーストを厚さ０．０２mmの銅箔
の両面に塗着し、乾燥後圧延して厚さ０．１９mm，幅４
０mm，長さ２８０mmの極板とした。The negative electrode is a carbon material 100 obtained by baking coke.
10 parts by weight of a fluororesin-based binder was mixed with parts by weight, and the mixture was suspended in an aqueous carboxymethylcellulose solution to form a paste. Then, this paste is applied to both sides of a 0.02 mm thick copper foil, dried and rolled to a thickness of 0.19 mm and a width of 4 mm.
The electrode plate was 0 mm in length and 280 mm in length.
【００１５】正極は活物質であるＬｉＣｏＯ2（詳細後
述）の粉末１００重量部に、アセチレンブラック３重量
部、グラファイト４重量部、フッ素樹脂系結着剤７重量
部を混合し、カルボキシメチルセルロース水溶液に懸濁
させてペース状にした。このペーストを厚さ０．０３mm
のアルミ箔の両面に塗着し、乾燥後圧延して厚さ０．１
８mm，幅４０mm，長さ２６０mmの極板とした。For the positive electrode, 100 parts by weight of powder of LiCoO 2 (described later in detail) was mixed with 3 parts by weight of acetylene black, 4 parts by weight of graphite, and 7 parts by weight of fluororesin binder to prepare an aqueous carboxymethyl cellulose solution. Suspended to pace. This paste is 0.03mm thick
Applied to both sides of aluminum foil, dried and rolled to a thickness of 0.1
The electrode plate was 8 mm wide, 40 mm wide and 260 mm long.
【００１６】そして正，負極それぞれにリードを取りつ
け、厚さ０．０２５mm，幅４６mm，長さ７００mmのポリ
プロピレン製の微孔性セパレータを介して渦巻き状に巻
回し、直径１３．８mm，高さ５０mmの電池ケース内に収
納した。電解液には炭酸プロピレンと炭酸エチレンの等
容積混合溶媒に、過塩素酸リチウムを１モル／ｌの割合
で溶解したものを用いて極板群４に注入した後、電池を
密封口し、供試電池とした。そしてこれらの供試電池を
充放電電流１００mA、充電終止電圧４．１Ｖ、放電終止
電圧３．０Ｖの条件下で定電流充放電試験を行った。Leads are attached to each of the positive and negative electrodes and spirally wound through a polypropylene microporous separator having a thickness of 0.025 mm, a width of 46 mm and a length of 700 mm, and a diameter of 13.8 mm and a height of 50 mm. It was stored in the battery case. The electrolyte solution was prepared by dissolving lithium perchlorate in a mixed solvent of equal volume of propylene carbonate and ethylene carbonate at a ratio of 1 mol / l, and injecting it into the electrode plate group 4, and then sealing the battery, It was a test battery. Then, these test batteries were subjected to a constant current charge / discharge test under the conditions of a charge / discharge current of 100 mA, a charge end voltage of 4.1 V, and a discharge end voltage of 3.0 V.
【００１７】以下、正極活物質の合成について詳しく説
明する。硝酸コバルト（Ｃｏ（ＮＯ3）2・ＸＨ2Ｏ）を
溶解したコバルト２価イオン水溶液に、コバルトイオン
に対し２モル等量の水酸化ナトリウム（ＮａＯＨ）水溶
液を徐々に加えていき、コバルト２価イオンを水酸基を
有するコバルト塩として沈殿させ、これをろ過しイオン
交換水で洗浄した後、酸化雰囲気下において２００℃で
５時間熱処理を行いコバルト酸化物を得た。図２（Ａ）
に得られたコバルト酸化物のＸ線回折図および同（Ｂ）
にその走査型電子顕微鏡写真を示す。図２（Ａ）のＸ線
回折図から本発明におけるコバルト酸化物は四三酸化コ
バルトと想定されるパターンを示しているが、回折ピー
ク半価幅が広いことから水酸化物などとの混合体と考え
られる。なお、４００℃以上で熱処理をした場合はコバ
ルトと同一な図示した。また走査型電子顕微鏡写真から
このコバルト酸化物は、市販されている通常のコバルト
酸化物と異なり、ほぼ球状もしくは長円球状で平均粒子
径が１μｍ以下の一次粒子が、複数個連接した凝集塊か
らなり、配向性の整った状態にあることがわかる。上記
のコバルト酸化物を、炭酸リチウムと原子比で１対１と
なるようにＶブレンダーで混合し、酸化雰囲気下におい
て９００℃で１０時間焼成してＬｉＣｏＯ2を合成し
た。合成されたＬｉＣｏＯ2は、軟らかい凝集塊状物と
して得られ、通常の粉砕機のように強い圧縮力や衝撃力
を加えて粉砕する必要はなく、弱い加圧力で容易に粉体
状にほぐれるものであり、スクリーンメッシュにより容
易に微粉体を得ることができる。従って、実施例では磁
性乳鉢を用いて凝集をほぐし、２８０メッシュのふるい
を用いて分別して活物質とした。図３に本合成法で合成
したＬｉＣｏＯ2の走査電子顕微鏡写真を示す。後述す
る従来の合成法で合成された従来例としてのＬｉＣｏＯ
2の走査型電子顕微鏡写真（図４）と比較してわかるよ
うに、粒子形状が粉砕工程によらないため、滑らかで規
則性があることがわかる。また粒径もほぼ均一であり
０．５μｍから３μｍである。The synthesis of the positive electrode active material will be described in detail below. To a cobalt divalent ion aqueous solution in which cobalt nitrate (Co (NO 3 ) 2 · XH 2 O) is dissolved, a sodium hydroxide (NaOH) aqueous solution in an amount of 2 moles relative to the cobalt ions is gradually added to form a cobalt divalent ion. Ions were precipitated as a cobalt salt having a hydroxyl group, filtered, washed with ion-exchanged water, and then heat-treated at 200 ° C. for 5 hours in an oxidizing atmosphere to obtain a cobalt oxide. Figure 2 (A)
X-ray diffraction diagram of the cobalt oxide obtained in (b)
The scanning electron micrograph is shown in FIG. From the X-ray diffraction diagram of FIG. 2 (A), the cobalt oxide in the present invention shows a pattern assumed to be cobalt trioxide, but since the half width of the diffraction peak is wide, it is a mixture with hydroxide or the like. it is conceivable that. It should be noted that when heat treatment is performed at 400 ° C. or higher, it is shown as the same as cobalt. In addition, from the scanning electron micrograph, this cobalt oxide is different from ordinary commercially available cobalt oxide, and is composed of agglomerates in which a plurality of primary particles having a substantially spherical or ellipsoidal shape and an average particle diameter of 1 μm or less are connected. Therefore, it can be seen that the orientation is in order. The above cobalt oxide was mixed with lithium carbonate in an atomic ratio of 1: 1 with a V blender, and baked at 900 ° C. for 10 hours in an oxidizing atmosphere to synthesize LiCoO 2 . The synthesized LiCoO 2 is obtained as a soft agglomerate and does not need to be crushed by applying a strong compressive force or impact force unlike a usual crusher, and can be easily loosened into a powder with a weak pressing force. With the screen mesh, fine powder can be easily obtained. Therefore, in the examples, the magnetic mortar was used to loosen the agglomerates, and the particles were separated using a 280 mesh sieve to obtain an active material. FIG. 3 shows a scanning electron micrograph of LiCoO 2 synthesized by this synthesis method. LiCoO as a conventional example synthesized by a conventional synthesis method described later
As can be seen by comparison with the scanning electron micrograph (No. 2 ) (Fig. 4), it is found that the particle shape does not depend on the crushing process, and thus is smooth and regular. The particle size is also substantially uniform and is 0.5 μm to 3 μm.
【００１８】この合成法により得られたＬｉＣｏＯ2を
活物質に用い、上述の条件で電池１を構成し、充放電サ
イクル試験を行った。LiCoO 2 obtained by this synthesis method was used as an active material, and a battery 1 was constructed under the above-mentioned conditions and a charge / discharge cycle test was conducted.
【００１９】従来例として、炭酸コバルトと炭酸リチウ
ムを原子比で１対１の割合でＶブレンダーで混合した混
合物を、酸化雰囲気下において９００℃で１０時間焼成
して得た硬い塊状物を、振動ボールミルで粉砕して２８
０メッシュのふるいを用いて分別して得たＬｉＣｏＯ2
を正極活物質とする電池２を上述した条件と同一な条件
で構成し、充放電サイクル試験を行った。As a conventional example, a hard lump obtained by firing a mixture of cobalt carbonate and lithium carbonate in a V-blender at an atomic ratio of 1: 1 in an oxidizing atmosphere at 900 ° C. for 10 hours was vibrated. 28 by crushing with a ball mill
LiCoO 2 obtained by fractionation using a 0 mesh sieve
A battery 2 having a positive electrode active material was constructed under the same conditions as described above, and a charge / discharge cycle test was performed.
【００２０】比較例として、通常の市販されている四三
酸化コバルト（コバルト化合物を熱分解，酸化するなど
で生成させたものを粉砕して粉体としたもの）と炭酸リ
チウムとを原子比で１対１の割合でＶブレンダーで混合
した混合物を、酸化雰囲気下において９００℃で１０時
間焼成して得た硬い塊状物を、振動ボールミルで粉砕し
２８０メッシュで分別したＬｉＣｏＯ2を正極活物質と
した電池３を上述した条件と同一なメッシュで分別した
ＬｉＣｏＯ2を正極活物質とした電池３を上述した条件
と同一な条件で構成し充放電サイクル試験を行った。こ
こで得られたＬｉＣｏＯ2の粉体は前記従来例で示した
図４の写真のものと粒子形状はほぼ同様であった。As a comparative example, ordinary commercially available cobalt trioxide (a powder produced by thermally decomposing and oxidizing a cobalt compound is pulverized into powder) and lithium carbonate in an atomic ratio. A hard lump obtained by firing a mixture obtained by mixing with a V blender at a ratio of 1: 1 in an oxidizing atmosphere at 900 ° C. for 10 hours was pulverized with a vibrating ball mill and fractionated with 280 mesh to form LiCoO 2 as a positive electrode active material. A battery 3 using LiCoO 2 as a positive electrode active material, which was obtained by separating the above battery 3 with the same mesh as the above conditions, was configured under the same conditions as the above conditions, and a charge / discharge cycle test was performed. The LiCoO 2 powder obtained here had substantially the same particle shape as that of the photograph of the conventional example shown in FIG.
【００２１】（表１）に電池１，電池２，電池３の５サ
イクル目の電池容量および正極活物質の容量密度を示
し、さらに１００サイクル目，２００サイクル目，３０
０サイクル目の容量維持率を各々の５サイクル目の容量
を１００として示す。電池１，電池２，電池３は、各々
同じ電池を１０個組み立てて試験を行い、（表１）には
各１０個の電池の平均値を示した。Table 1 shows the battery capacities of the battery 1, battery 2 and battery 3 at the 5th cycle and the capacity density of the positive electrode active material. Further, the 100th cycle, the 200th cycle, the 30th cycle.
The capacity retention rate at the 0th cycle is shown by setting the capacity at the 5th cycle to 100. For battery 1, battery 2, and battery 3, 10 same batteries were assembled and tested, and (Table 1) shows the average value of each 10 batteries.
【００２２】[0022]
【表１】 [Table 1]
【００２３】この試験結果から本発明によるリチウムコ
バルト複合酸化物（ＬｉＣｏＯ2）を正極活物質に使用
した電池は充放電サイクル特性に優れていることがわか
る。また本発明によるＬｉＣｏＯ2は粒径が均一かつ細
かく、粒子形状が滑らかで規則性があるため、活物質の
充填量および容量密度が上がり電池容量が増加した。From these test results, it is understood that the battery using the lithium cobalt composite oxide (LiCoO 2 ) according to the present invention as the positive electrode active material is excellent in charge / discharge cycle characteristics. Moreover, since the particle size of LiCoO 2 according to the present invention is uniform and fine, the particle shape is smooth and regular, the filling amount and capacity density of the active material are increased and the battery capacity is increased.
【００２４】従来例としての電池２はサイクルが進むに
つれて大幅に容量低下が起こっている。充放電サイクル
後、Ｘ線回折図から判断して格子破壊は認められない
が、粒子の割れを含む粒子形状を因子とする、集電体か
らの活物質の脱離が容量低下の原因であると思われる。The capacity of the battery 2 as a conventional example is greatly reduced as the cycle progresses. After the charging / discharging cycle, no lattice breakage is recognized from the X-ray diffraction diagram, but the desorption of the active material from the current collector, which is caused by the particle shape including particle cracking, is the cause of the capacity decrease. I think that the.
【００２５】比較例としての電池３は、従来例（電池
２）と比べて充放電サイクルに伴う容量低下が少なくな
っているが本発明における電池１に見られるような充分
な特性を出すには至っていない。これは、ＬｉＣｏＯ2
の合成反応が比較例におけるＬｉＣｏＯ2の合成と比べ
て良好に進んでいるため、粒子の割れが比較的少ないこ
とにより従来例に比較して良好であるが、合成後の塊状
物は固く焼結し機械的な力で粉砕する必要があり、粒子
形状が不定形となるため、従来例と同様の課題を残して
いるので、充分な特性を出すには至っていないと考えら
れる。The battery 3 as a comparative example has less decrease in capacity with charging / discharging cycle as compared with the conventional example (battery 2), but in order to obtain sufficient characteristics as seen in the battery 1 of the present invention. I haven't arrived. This is LiCoO 2
Since the synthesis reaction of (1) is better than the synthesis of LiCoO 2 in the comparative example, it is better than the conventional example due to relatively few particle cracks, but the lumps after synthesis are hard and sintered. However, since it is necessary to pulverize by mechanical force and the particle shape becomes indefinite, the same problems as in the conventional example remain, and it is considered that sufficient characteristics have not been achieved yet.
【００２６】なお、一次粒子径を２μｍから５μｍ程度
に大きくした、水酸基を有するコバルト塩を熱処理して
得たコバルト酸化物を、コバルト源として合成したＬｉ
ＣｏＯ2は、単位粒子径が５μｍから３０μｍ程度とな
り、前記したように、シート状正極板を形成して用いる
場合は、塗着充填量が減少し、また、合成後の塊状物は
凝集力が大きくなっており、従来例あるいは比較例の場
合と同様に強い力で粉砕する必要があり、結果的に比較
例と同様の課題を残すので好ましくない。A cobalt oxide obtained by heat-treating a cobalt salt having a hydroxyl group, the primary particle diameter of which was increased from 2 μm to 5 μm, was synthesized as a cobalt source.
CoO 2 has a unit particle size of about 5 μm to 30 μm, and as described above, when the sheet-shaped positive electrode plate is formed and used, the coating filling amount is reduced, and the lumps after synthesis have a cohesive force. Since it is large, it is necessary to grind with a strong force as in the case of the conventional example or the comparative example, and as a result, the same problem as the comparative example remains, which is not preferable.
【００２７】本実施例では硝酸コバルトと水酸化ナトリ
ウムからコバルト水酸化物を調製したが、コバルト塩は
塩化コバルト，硫酸コバルト，酢酸コバルトなどでもよ
く、水に溶解しコバルト２価イオンの水溶液を生じるも
のならば同様の効果を与える。またアルカリ溶液は水酸
化ナトリウムに限らず水酸化リチウム，水酸化カリウム
でも同様に用いることができ、コバルトイオンに対し加
える量も厳密に２モル当量である必要はなく、１モル当
量以上であれば水酸基を有するコバルト塩が得られ熱分
解において同様のコバルト酸化物が得られ、本実施例と
同様のリチウムコバルト複合酸化物が合成できることを
確認した。さらに水酸基を有するコバルト塩を酸化雰囲
気下で熱処理する場合、１００℃から９００℃の温度範
囲では熱処理後のコバルト酸化物の粒子状態に変化はな
く本実施例と同様なリチウムコバルト複合酸化物が得ら
れる。In this example, cobalt hydroxide was prepared from cobalt nitrate and sodium hydroxide, but the cobalt salt may be cobalt chloride, cobalt sulfate, cobalt acetate, etc., and it is dissolved in water to form an aqueous solution of divalent cobalt ions. If it is one, it gives the same effect. Further, the alkaline solution is not limited to sodium hydroxide, and lithium hydroxide and potassium hydroxide can be similarly used, and the amount to be added to the cobalt ion does not have to be exactly 2 molar equivalents, and may be 1 molar equivalent or more. It was confirmed that a cobalt salt having a hydroxyl group was obtained, a similar cobalt oxide was obtained by thermal decomposition, and a lithium cobalt composite oxide similar to that of this example could be synthesized. Further, when the cobalt salt having a hydroxyl group is heat-treated in an oxidizing atmosphere, there is no change in the particle state of the cobalt oxide after the heat treatment in the temperature range of 100 ° C. to 900 ° C., and a lithium cobalt composite oxide similar to this example is obtained. Be done.
【００２８】もちろん純粋なリチウムコバルト複合酸化
物に限らず、少量のニッケル，鉄，マンガン，アルミニ
ウム，スズなどの他元素が固溶または不純物として存在
する系においても本実施例と同様の効果が得られる。Of course, not only the pure lithium-cobalt composite oxide, but also the system in which a small amount of other elements such as nickel, iron, manganese, aluminum and tin are present as a solid solution or as an impurity, the same effect as this embodiment can be obtained. Be done.
【００２９】[0029]
【発明の効果】以上の説明から明らかなように、本発明
は上記した特定の条件で合成されたリチウムコバルト複
合酸化物を正極活物質に用いたことにより、高電圧，高
容量を有し、充放電サイクル特性に優れた非水電解液二
次電池を提供することができる。As is apparent from the above description, the present invention has a high voltage and a high capacity by using the lithium cobalt composite oxide synthesized under the above specific conditions as a positive electrode active material. A non-aqueous electrolyte secondary battery having excellent charge / discharge cycle characteristics can be provided.
【図１】本発明の実施例における円筒形電池の縦断面図FIG. 1 is a vertical sectional view of a cylindrical battery according to an embodiment of the present invention.
【図２】（Ａ）コバルト２価イオンの水溶液にアルカリ
溶液を混合した後、分離した水酸基を有するコバルト塩
の沈殿物を２００℃で熱処理を加えて得たコバルト酸化
物のＸ線回折図 （Ｂ）その粒子構造を示す走査型電子顕微鏡写真FIG. 2 (A) An X-ray diffraction diagram of cobalt oxide obtained by mixing an alkaline solution with an aqueous solution of divalent cobalt ions and then subjecting the separated precipitate of the cobalt salt having a hydroxyl group to heat treatment at 200 ° C. B) Scanning electron micrograph showing the grain structure.
【図３】本発明により合成されたＬｉＣｏＯ2の粒子構
造を示す走査型電子顕微鏡写真FIG. 3 is a scanning electron micrograph showing the particle structure of LiCoO 2 synthesized according to the present invention.
【図４】従来の合成法で得られたＬｉＣｏＯ2の粒子構
造を示す走査型電子顕微鏡写真FIG. 4 is a scanning electron micrograph showing the particle structure of LiCoO 2 obtained by a conventional synthesis method.
１ 電池ケース ２ 封口板 ３ 絶縁パッキング ４ 極板群 ５ 正極リード ６ 負極リード ７ 絶縁リング 1 Battery case 2 Sealing plate 3 Insulation packing 4 Electrode plate group 5 Positive electrode lead 6 Negative electrode lead 7 Insulation ring
───────────────────────────────────────────────────── フロントページの続き (72)発明者 伊藤 善一郎 大阪府門真市大字門真1006番地 松下電器 産業株式会社内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Zenichiro Ito 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.
Claims (2)
ウム含有複合酸化物を活物質とする正極とを備えた非水
電解液二次電池において、コバルト源として、形成がほ
ぼ球状もしくは長円球状で平均粒子径が１μｍ以下の一
次粒子が、複数個連接した凝集塊からなるコバルト酸化
物を用い、これとリチウム塩との混合物を、酸化雰囲気
下において６００℃から１１００℃の温度範囲で焼成す
ることで合成される、式ＬｉXＣｏＯ2（０．９０≦Ｘ≦
１．０５）で表されるリチウムコバルト複合酸化物を正
極活物質として用いることを特徴とする非水電解液二次
電池の製造法。1. A non-aqueous electrolyte secondary battery comprising a rechargeable negative electrode, a non-aqueous electrolyte, and a positive electrode using a lithium-containing composite oxide as an active material. Alternatively, a cobalt oxide composed of an agglomerate in which a plurality of primary particles having an ellipsoidal shape and an average particle diameter of 1 μm or less are connected to each other is used, and a mixture of this and a lithium salt is used in an oxidizing atmosphere at a temperature of 600 ° C. to 1100 ° C. Formula Li X CoO 2 (0.90 ≦ X ≦) synthesized by firing in the range
1.05) is used as a positive electrode active material of the lithium-cobalt composite oxide, and a method for producing a non-aqueous electrolyte secondary battery.
液を混合して生成沈殿する、水酸基を有するコバルト塩
を分離した後、酸化雰囲気下において１００℃ないし９
００℃以下の範囲の温度で熱処理を行うことで得た、コ
バルト酸化物をコバルト源に用いて合成したリチウムコ
バルト複合酸化物を正極活物質とする請求項１記載の非
水電解液二次電池の製造法。2. A cobalt salt having a hydroxyl group, which is produced and precipitated by mixing an alkaline solution with an aqueous solution of divalent cobalt ions, is separated, and then the mixture is heated at 100 ° C. to 9 ° C. in an oxidizing atmosphere.
The non-aqueous electrolyte secondary battery according to claim 1, wherein the positive electrode active material is a lithium-cobalt composite oxide obtained by performing heat treatment at a temperature in the range of 00 ° C. or lower and synthesized using cobalt oxide as a cobalt source. Manufacturing method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3244508A JP2855912B2 (en) | 1991-08-28 | 1991-08-28 | Manufacturing method of non-aqueous electrolyte secondary battery |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3244508A JP2855912B2 (en) | 1991-08-28 | 1991-08-28 | Manufacturing method of non-aqueous electrolyte secondary battery |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0554888A true JPH0554888A (en) | 1993-03-05 |
| JP2855912B2 JP2855912B2 (en) | 1999-02-10 |
Family
ID=17119723
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3244508A Expired - Lifetime JP2855912B2 (en) | 1991-08-28 | 1991-08-28 | Manufacturing method of non-aqueous electrolyte secondary battery |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2855912B2 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1999049528A1 (en) * | 1998-03-23 | 1999-09-30 | Sumitomo Metal Mining Co., Ltd. | Active material of positive electrode for non-aqueous electrode secondary battery and method for preparing the same and non-aqueous electrode secondary battery using the same |
| KR100816116B1 (en) * | 2000-06-19 | 2008-03-24 | 나노그램 코포레이션 | Lithium metal oxides |
| US20150252929A1 (en) * | 2012-11-22 | 2015-09-10 | Mantaray Innovations Limited | Flexible pipe and coupling therefor |
| US20160153598A1 (en) * | 2013-07-04 | 2016-06-02 | Símeros Projetos Eletromecânicos Ltda | Connector for flexible duct |
-
1991
- 1991-08-28 JP JP3244508A patent/JP2855912B2/en not_active Expired - Lifetime
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1999049528A1 (en) * | 1998-03-23 | 1999-09-30 | Sumitomo Metal Mining Co., Ltd. | Active material of positive electrode for non-aqueous electrode secondary battery and method for preparing the same and non-aqueous electrode secondary battery using the same |
| KR100816116B1 (en) * | 2000-06-19 | 2008-03-24 | 나노그램 코포레이션 | Lithium metal oxides |
| US20150252929A1 (en) * | 2012-11-22 | 2015-09-10 | Mantaray Innovations Limited | Flexible pipe and coupling therefor |
| US20150330536A1 (en) * | 2012-11-22 | 2015-11-19 | Mantaray Innovations Limited | Flexible pipe and coupling therefor |
| US9587772B2 (en) * | 2012-11-22 | 2017-03-07 | Mantaray Innovations Limited | Flexible pipe and coupling therefor |
| US10066765B2 (en) * | 2012-11-22 | 2018-09-04 | Mantaray Innovations Limited | Flexible pipe and coupling therefor |
| US20160153598A1 (en) * | 2013-07-04 | 2016-06-02 | Símeros Projetos Eletromecânicos Ltda | Connector for flexible duct |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2855912B2 (en) | 1999-02-10 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP3232984B2 (en) | Method for producing nonaqueous electrolyte battery and positive electrode active material | |
| JP3047693B2 (en) | Non-aqueous electrolyte secondary battery and method for producing positive electrode active material thereof | |
| JP2002110162A (en) | Positive electrode active material and nonaqueous electrolytic battery | |
| JPH08124559A (en) | Manufacture of lithium secondary battery and of negative electrode active material | |
| JP2002117833A (en) | Nonaqueous electrolyte secondary battery | |
| JP2005222953A (en) | Positive electrode active material used for lithium secondary battery, method of manufacturing the same, and lithium secondary battery including the same | |
| JP4268613B2 (en) | Method for producing positive electrode active material for lithium secondary battery | |
| JP5804427B2 (en) | Method for producing positive electrode active material for secondary battery | |
| WO2012002122A1 (en) | Method for producing porous lithium titanate, porous lithium titanate and lithium battery using same | |
| JP4344359B2 (en) | Positive electrode material for lithium secondary battery and method for producing the same | |
| JP4878861B2 (en) | Non-aqueous electrolyte battery | |
| JPH07226204A (en) | Manufacture of nonaqueous electrolyte secondary battery | |
| JPH02139860A (en) | Non-aqueous electrolyte secondary battery and manufacture of positive electrode active substance therefor | |
| JPH02139861A (en) | Non-aqueous electrolyte secondary battery | |
| JP2001243949A (en) | Lithium transition metal oxide compound for lithium secondary battery positive electrode active material, its manufacturing method and secondary battery using it | |
| JPH1160243A (en) | Nickel hydroxide, lithium nickelate, their production and lithium ion secondary battery using the lithium nickelate | |
| JP3257350B2 (en) | Non-aqueous electrolyte secondary battery and method for producing its positive electrode active material | |
| JP3396076B2 (en) | Method for producing lithium cobaltate-based positive electrode active material for lithium secondary battery | |
| JP2002124258A (en) | Lithium manganate particle powder and its manufacturing method | |
| JPH10162830A (en) | Positive electrode active material for lithium secondary battery, and secondary battery using same | |
| JP2002117843A (en) | Nonaqueous electrolyte secondary battery | |
| JP2855912B2 (en) | Manufacturing method of non-aqueous electrolyte secondary battery | |
| JPH1064592A (en) | Lithium secondary battery | |
| JPH06275276A (en) | Manufacture of spinel limn2o4 with high surface area and its application to nonaqueous battery | |
| JP3751133B2 (en) | Method for producing positive electrode active material for non-aqueous electrolyte secondary battery |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20071127 Year of fee payment: 9 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20081127 Year of fee payment: 10 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20091127 Year of fee payment: 11 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20091127 Year of fee payment: 11 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20101127 Year of fee payment: 12 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20111127 Year of fee payment: 13 |
|
| EXPY | Cancellation because of completion of term | ||
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20111127 Year of fee payment: 13 |