JPH08213014A - Nonaqueous electrolyte secondary battery - Google Patents
Nonaqueous electrolyte secondary batteryInfo
- Publication number
- JPH08213014A JPH08213014A JP7017631A JP1763195A JPH08213014A JP H08213014 A JPH08213014 A JP H08213014A JP 7017631 A JP7017631 A JP 7017631A JP 1763195 A JP1763195 A JP 1763195A JP H08213014 A JPH08213014 A JP H08213014A
- Authority
- JP
- Japan
- Prior art keywords
- lithium
- composite oxide
- transition metal
- oxide particles
- secondary battery
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
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、非水電解液二次電池に
関し、特に正極活物質の改良に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-aqueous electrolyte secondary battery, and more particularly to improvement of a positive electrode active material.
【０００２】[0002]
【従来の技術】近年、種々の電子機器の飛躍的進歩に伴
い、長時間安定且つ経済的に使用できるポータブル電源
として二次電池の研究が進められている。2. Description of the Related Art In recent years, with the rapid progress of various electronic devices, research on secondary batteries has been advanced as a portable power source that can be used stably and economically for a long time.
【０００３】代表的な二次電池としては、Ｎｉ−Ｃｄ蓄
電池、鉛蓄電池、アルカリ蓄電池、リチウム二次電池等
が挙げられるが、中でもリチウム二次電池（非水電解液
二次電池）は他の二次電池に比べて高出力、高エネルギ
ー密度を達成できることから活発に研究が行われ、材料
構成も各種提案がなされている。Typical secondary batteries include Ni-Cd storage batteries, lead storage batteries, alkaline storage batteries, lithium secondary batteries, and the like. Among them, lithium secondary batteries (non-aqueous electrolyte secondary batteries) are other types. Since it can achieve higher output and higher energy density than a secondary battery, it is actively researched and various material configurations have been proposed.
【０００４】たとえば、このようなリチウム二次電池の
負極活物質としては、一般に、金属リチウムまたはリチ
ウム合金の他、リチウムをドープ・脱ドープできる材料
が使用されている。このリチウムをドープ・脱ドープで
きる材料とは、リチウムをドープした導電性高分子もし
くは炭素材料や金属酸化物のような層状化合物である。For example, as a negative electrode active material for such a lithium secondary battery, in general, metallic lithium or a lithium alloy as well as a material capable of doping / dedoping lithium are used. The material capable of being doped with lithium and dedoped is a conductive polymer doped with lithium or a layered compound such as a carbon material or a metal oxide.
【０００５】一方、正極活物質としては、金属酸化物、
金属硫化物、特定のポリマーが使用される。具体的に
は、ＴｉＳ2、ＭｏＳ2、ＮｂＳｅ2、Ｖ2Ｏ5等のリチウ
ムを含有しない化合物やＬｉＭＯ2（但し、ＭはＣｏ、
Ｎｉ、Ｍｎ、Ｆｅ等である）で表されるリチウムと遷移
金属の複合酸化物が挙げられる。On the other hand, as the positive electrode active material, a metal oxide,
Metal sulfides, certain polymers are used. Specifically, compounds containing no lithium such as TiS 2 , MoS 2 , NbSe 2 , V 2 O 5 and LiMO 2 (where M is Co,
Ni, Mn, Fe, etc.) and a composite oxide of lithium and a transition metal.
【０００６】また、負極と正極の間に介在させるセパレ
ータには、ポリプロピレン等よりなる高分子フィルムが
用いられる。このセパレータとなる高分子フィルムは、
リチウムイオンの伝導度とエネルギー密度の点から可能
なかぎり薄くすることが求められ、通常５０μｍ以下の
厚さで用いられる。A polymer film made of polypropylene or the like is used for the separator interposed between the negative electrode and the positive electrode. The polymer film that becomes this separator is
It is required to be as thin as possible in terms of lithium ion conductivity and energy density, and it is usually used in a thickness of 50 μm or less.
【０００７】そして、電解液としては、非水溶媒にリチ
ウム塩を電解質として溶解させた非水電解液が用いられ
る。As the electrolytic solution, a nonaqueous electrolytic solution prepared by dissolving a lithium salt in a nonaqueous solvent as an electrolyte is used.
【０００８】[0008]
【発明が解決しようとする課題】しかしながら、上述の
ような材料で構成されるリチウム二次電池は、Ｎｉ−Ｃ
ｄ蓄電池等、従来の二次電池に比べれば高いエネルギー
密度を有するものの、近年のポータブル機器の性能の向
上に対応するには、さらなる容量の向上が望まれる。However, the lithium secondary battery made of the above-mentioned materials is Ni--C.
Although it has a higher energy density than conventional secondary batteries such as d storage batteries, further improvement in capacity is desired in order to cope with recent improvements in the performance of portable devices.
【０００９】ここで、電池の容量を向上させるには、ま
ず充電電圧を上げることが容易な方法である。ところ
が、上記リチウム二次電池で充電電圧を上昇させると、
電解液の酸化、分解が引き起こる。そして、そのような
高い充電電圧で充放電を繰り返し行っていると、容量が
段々に減少してくる。Here, in order to improve the capacity of the battery, it is easy to increase the charging voltage first. However, when the charging voltage is increased with the lithium secondary battery,
This causes oxidation and decomposition of the electrolyte. Then, when charging and discharging are repeatedly performed at such a high charging voltage, the capacity gradually decreases.
【００１０】この充電電圧を上昇させることで生じる電
解液の分解は、電解液の安定性及び電極表面の性質に密
接に関係しているものと考えられるが、確かな原因は判
明しておらず、防止する方法は見い出されていない。It is considered that the decomposition of the electrolytic solution caused by increasing the charging voltage is closely related to the stability of the electrolytic solution and the property of the electrode surface, but the definite cause has not been clarified. , No way to prevent has been found.
【００１１】また、上記リチウム二次電池では、夏期の
車中での使用等を考えた場合、高温保存下での自己放電
を抑制することも重要な課題である。Further, in the lithium secondary battery, in consideration of use in a vehicle in the summer, it is also an important issue to suppress self-discharge under high temperature storage.
【００１２】この自己放電の原因としては、両極の活物
質と電解液の界面で起こる電解液の分解と被膜の形成、
あるいはこれら活物質の構造変化、さらには正極活物質
に含まれている遷移金属元素の溶出等が考えられてい
る。しかし、やはりこれらを防止する適当な手法は見い
出されておらず、自己放電の問題も依然として解消され
ていない。The cause of this self-discharge is decomposition of the electrolytic solution and formation of a film at the interface between the active material of both electrodes and the electrolytic solution.
Alternatively, structural changes of these active materials and further elution of transition metal elements contained in the positive electrode active material are considered. However, no suitable method for preventing them has been found, and the problem of self-discharge has not been solved.
【００１３】そこで、本発明はこのような従来の実情に
鑑みて提案されたものであり、高い充電電圧で高温環境
下に保存した場合にも、電解液が分解し難く、電解液の
分解によって生じる容量減少及び自己放電が抑えられる
非水電解液二次電池を提供することを目的とする。Therefore, the present invention has been proposed in view of such a conventional situation, and the electrolyte is difficult to decompose even when it is stored in a high temperature environment at a high charging voltage. It is an object of the present invention to provide a non-aqueous electrolyte secondary battery in which the capacity decrease and self-discharge that occur are suppressed.
【００１４】[0014]
【課題を解決するための手段】上述の目的を達成するた
めに、本発明者等が鋭意検討を重ねた結果、正極活物質
としてフッ素化処理が施されたリチウム遷移金属複合酸
化物を用いることで、高い充電電圧で高温環境下に保存
したときに生じる電解液の分解が抑えられるとの知見を
得るに至った。In order to achieve the above object, the inventors of the present invention have made extensive studies and as a result, use of a fluorinated lithium transition metal composite oxide as a positive electrode active material. Thus, it has been found that decomposition of the electrolytic solution that occurs when stored in a high temperature environment at a high charging voltage can be suppressed.
【００１５】本発明の非水電解液二次電池はこのような
知見に基づいて完成されたものであり、リチウムと遷移
金属の複合酸化物粒子を含有する正極と、リチウムをド
ープ・脱ドープできる炭素材料、リチウム金属またはリ
チウム合金のいずれかを含有する負極と、リチウム塩を
非水溶媒に溶解してなる非水電解液を有してなる非水電
解液二次電池において、上記複合酸化物粒子は、表面が
フッ素化処理されていることを特徴とするものである。The non-aqueous electrolyte secondary battery of the present invention has been completed based on such findings, and it is possible to dope and de-dope lithium with a positive electrode containing composite oxide particles of lithium and a transition metal. In the non-aqueous electrolyte secondary battery comprising a carbon material, a negative electrode containing any one of lithium metal or a lithium alloy, and a non-aqueous electrolyte solution obtained by dissolving a lithium salt in a non-aqueous solvent, the above composite oxide. The particles are characterized in that their surfaces are fluorinated.
【００１６】すなわち、本発明では、正極活物質として
表面がフッ素化処理されたリチウム遷移金属複合酸化物
粒子を用いる。表面がフッ素化処理されたリチウム遷移
金属複合酸化物粒子を正極に用いると、当該電池を高温
環境下で保存したり、高い充電電圧で充放電を行った場
合でも、電解液が分解し難く、高容量が維持されるとと
もに自己放電が抑えられる。That is, in the present invention, lithium transition metal composite oxide particles whose surfaces are fluorinated are used as the positive electrode active material. When the surface is fluorinated lithium transition metal composite oxide particles used for the positive electrode, the battery is stored in a high temperature environment, even when charged and discharged at a high charging voltage, the electrolyte is difficult to decompose, High capacity is maintained and self-discharge is suppressed.
【００１７】このフッ素化処理が施されるリチウム遷移
金属複合酸化物粒子は、遷移金属としてニッケル、コバ
ルト、マンガンの少なくともいずれかを含有するものが
望ましく、たとえばＬｉＮｉＯ2、ＬｉＮｉxＣｏ
1-xＯ2、ＬｉＭｎＯ2、ＬｉＭｎ2Ｏ4等が挙げられる。The lithium-transition metal composite oxide particles to be fluorinated are preferably those containing at least one of nickel, cobalt and manganese as a transition metal. For example, LiNiO 2 , LiNi x Co.
1-x O 2 , LiMnO 2 , LiMn 2 O 4 and the like can be mentioned.
【００１８】これらリチウム遷移金属複合酸化物粒子を
フッ素化処理する方法としては、まず、Ｒ1Ｒ2Ｒ3Ｒ4Ｎ
Ｆ（但し、Ｒ1，Ｒ2，Ｒ3，Ｒ4はＨまたは炭素数が１〜
４のアルキル基、例えばＣＨ3，Ｃ2Ｈ5，Ｃ4Ｈ9等を表
す）で示されるフッ素化合物を用いる方法がある。この
フッ素化合物を溶解した溶液中に、処理すべき複合酸化
物粒子を浸漬し、所定時間放置する。その結果、目的と
するところの表面がフッ化された複合酸化物粒子が得ら
れる。As a method of fluorinating these lithium-transition metal composite oxide particles, first, R 1 R 2 R 3 R 4 N is used.
F (provided that R 1 , R 2 , R 3 and R 4 are H or have 1 to 1 carbon atoms)
4 alkyl group, for example, CH 3 , C 2 H 5 , C 4 H 9 and the like) is used. The composite oxide particles to be treated are immersed in the solution in which the fluorine compound is dissolved, and left for a predetermined time. As a result, the desired surface-fluorinated complex oxide particles are obtained.
【００１９】この他、フッ素化処理の方法として、Ｆ2
ガスと直接反応させる方法やＮＦ3ガスと接触させる方
法（第３４回 電池討論回予稿集ｐ６１）、ＡＨＦ（ａ
ｎｈｙｄｒｏｕｓ Ｈｙｄｒｏｇｅｎ Ｆｌｕｏｒｉｄ
ｅ）を用いる方法、さらにペルフルオロ化合物による光
化学フッ素化法等を用いるようにしても良い。In addition to this, as a method of fluorination treatment, F 2
Direct reaction with gas or contact with NF 3 gas (Proceedings of the 34th Battery Discussion Session p61), AHF (a
nhydrogen Fluorid
The method using e), or the photochemical fluorination method using a perfluoro compound may be used.
【００２０】本発明では、以上のように表面がフッ素化
処理されたリチウム遷移金属複合酸化物粒子を正極に用
いるが、負極や非水電解液には以下のような材料が用い
られる。In the present invention, the lithium-transition metal composite oxide particles whose surfaces are fluorinated as described above are used for the positive electrode, but the following materials are used for the negative electrode and the non-aqueous electrolyte.
【００２１】まず、負極の材料には、リチウムをドープ
・脱ドープできる材料や金属リチウム、リチウム合金が
使用される。このうちリチウム合金としてはリチウム−
アルミニウム合金等を使用できる。また、リチウムをド
ープ・脱ドープできる材料としては、例えば熱分解炭素
類、コークス類（ピッチコークス、ニードルコークス、
石油コークス等）、グラファイト類、ガラス状炭素類、
有機高分子化合物焼成体（フェノール樹脂、フラン樹脂
等を適当な温度で焼成し、炭素化したもの）、炭素繊
維、活性炭等の炭素質材料、あるいはポリアセチレン、
ポリピロール等のポリマー等が挙げられる。First, as the material of the negative electrode, a material capable of being doped or dedoped with lithium, metallic lithium, or a lithium alloy is used. Of these, lithium is the lithium alloy
Aluminum alloy or the like can be used. Further, as a material capable of doping / dedoping lithium, for example, pyrolytic carbons, cokes (pitch coke, needle coke,
Petroleum coke, etc.), graphites, glassy carbons,
Carbonized material such as organic polymer compound fired product (phenolic resin, furan resin, etc. fired at appropriate temperature to carbonize), carbon fiber, activated carbon, or polyacetylene,
Examples thereof include polymers such as polypyrrole.
【００２２】また、非水電解液の非水溶媒としては、プ
ロピレンカーボネート、エチレンカーボネート、ブチレ
ンカーボネート、ビニレンカーボネート、γ−ブチルラ
クトン、スルホラン、１，２−ジメトキシエタン、１，
２−ジエトキシエタン、２−メチルテトラヒドロフラ
ン、３−メチル−１，３−ジオキソラン、プロピオン酸
メチル、酪酸メチル、ジメチルカーボネート、ジエチル
カーボネート、ジプロピルカーボネート等が使用でき
る。特に、プロピレンカーボネート、ビニレンカーボネ
ート等の環状カーボネート類、ジメチルカーボネート、
ジエチルカーボネート、ジプロピルカーボネート等の鎖
状カーボネート類は優れた耐酸化還元性、広幅な電位窓
を持つことから望ましい。なお、以上に列挙した溶媒は
単独で用いても２種類以上を組み合わせて用いても良
い。As the non-aqueous solvent of the non-aqueous electrolyte, propylene carbonate, ethylene carbonate, butylene carbonate, vinylene carbonate, γ-butyl lactone, sulfolane, 1,2-dimethoxyethane, 1,
2-diethoxyethane, 2-methyltetrahydrofuran, 3-methyl-1,3-dioxolane, methyl propionate, methyl butyrate, dimethyl carbonate, diethyl carbonate, dipropyl carbonate and the like can be used. In particular, propylene carbonate, cyclic carbonates such as vinylene carbonate, dimethyl carbonate,
Chain carbonates such as diethyl carbonate and dipropyl carbonate are desirable because they have excellent redox resistance and a wide potential window. The solvents listed above may be used alone or in combination of two or more.
【００２３】非水溶媒に溶解させる電解質としては、例
えばＬｉＰＦ6、ＬｉＣｌＯ4、ＬｉＡｓＦ6、ＬｉＢ
Ｆ4、ＬｉＣＦ3ＳＯ3、ＬｉＮ（ＣＦ3ＳＯ2）2等が使用
でき、このうちＬｉＰＦ6やＬｉＢＦ4を使用するのが好
ましい。As the electrolyte to be dissolved in the non-aqueous solvent, for example, LiPF 6 , LiClO 4 , LiAsF 6 , LiB
F 4 , LiCF 3 SO 3 , LiN (CF 3 SO 2 ) 2 and the like can be used, and among these, LiPF 6 and LiBF 4 are preferably used.
【００２４】なお、電池には、このような液状の電解液
の代わりに固体電解質を用いるようにしても良い。A solid electrolyte may be used in the battery instead of such a liquid electrolyte.
【００２５】本発明の非水電解液二次電池では、具体的
には、以上のような正極材料、すなわちフッ素化処理が
施された酸化物微粒子を導電剤、結着材、有機溶剤とと
もに混練、圧縮成形することで正極電極が構成され、ま
た上記負極材料を結着材、有機溶剤とともに混練、圧縮
成形することで負極電極が構成される。たとえばコイン
型電池は、これら正極電極、負極電極がそれぞれ収容さ
れた正極缶、負極缶を、電極同士が対向するようにセパ
レータを介して積層するとともに電界液を含浸させ、缶
の外周縁部をかしめ密閉することで構成される。なお、
電池の形状は、コイン型に限定されず、円筒型、角型、
ボタン型等いずれでも良い。In the non-aqueous electrolyte secondary battery of the present invention, specifically, the above-mentioned positive electrode material, that is, fluorinated oxide fine particles are kneaded together with a conductive agent, a binder and an organic solvent. The positive electrode is formed by compression molding, and the negative electrode is formed by kneading and compression molding the negative electrode material together with a binder and an organic solvent. For example, in a coin-type battery, a positive electrode can and a negative electrode can, in which the positive electrode and the negative electrode are respectively housed, are stacked via a separator so that the electrodes face each other and impregnated with an electrolytic solution, and the outer peripheral portion of the can is Consists of caulking and sealing. In addition,
The shape of the battery is not limited to a coin type, but a cylindrical type, a square type,
Either button type or the like may be used.
【００２６】[0026]
【作用】非水電解液二次電池において、正極材料となる
リチウムと遷移金属の複合酸化物粒子として表面がフッ
素化処理されたものを用いると、電池を高温環境下で保
存したり、高い充電電圧で充放電を行った場合でも、電
解液が分解し難く、高容量が維持されるとともに自己放
電が抑えられる。これは以下のような理由によるものと
推測される。[Function] In the non-aqueous electrolyte secondary battery, when the surface of the composite oxide particles of lithium and transition metal, which is the positive electrode material, whose surface is fluorinated is used, the battery can be stored in a high temperature environment or charged with high charge. Even when the battery is charged and discharged, the electrolytic solution is difficult to decompose, a high capacity is maintained, and self-discharge is suppressed. It is assumed that this is due to the following reasons.
【００２７】まず、一般に、フッ素化処理が施されてい
ないリチウム遷移金属複合酸化物粒子には、その表面に
酸素−遷移金属結合が多数存在する。遷移金属酸化物
は、有機化合物の分解反応を促進する触媒としても利用
されており、当然、有機化合物である非水溶媒に対して
も同様な作用を有すると考えられる。First, in general, the lithium-transition metal composite oxide particles that have not been subjected to the fluorination treatment have many oxygen-transition metal bonds on the surface thereof. The transition metal oxide is also used as a catalyst for accelerating the decomposition reaction of the organic compound, and naturally, it is considered that the transition metal oxide also has a similar effect to the non-aqueous solvent which is the organic compound.
【００２８】すなわち、正極材料となるリチウム遷移金
属複合酸化物粒子が非水溶媒に作用を及ぼす様子を推測
すると、当該リチウム遷移金属複合酸化物粒子の最表面
層の酸素が溶媒に求核的に働き、非水溶媒分子の電子密
度の低い部所や水素原子と弱い結合を形成する。その結
果、溶媒の安定性が低下し、溶媒の分解が起こるものと
考えられる。That is, assuming that the lithium-transition metal composite oxide particles serving as the positive electrode material act on the non-aqueous solvent, the oxygen in the outermost surface layer of the lithium-transition metal composite oxide particles is nucleophilically determined by the solvent. It works and forms a weak bond with the hydrogen atom and the low electron density part of the non-aqueous solvent molecule. As a result, it is considered that the stability of the solvent is lowered and the solvent is decomposed.
【００２９】このように正極表面で、溶媒の分解が起き
ると、その分解生成物によって正極表面の電荷移動抵抗
が時間とともに増加する。また、溶媒の分解には、電気
量の消費が伴い、このため自己放電も誘発される。溶媒
の分解は温度の上昇に従って激しくなるので、このよう
な電荷移動抵抗の増加や自己放電も高温環境下では一層
促進されることになる。When the solvent is decomposed on the positive electrode surface as described above, the decomposition product increases the charge transfer resistance of the positive electrode surface with time. In addition, the decomposition of the solvent is accompanied by the consumption of electricity, which also induces self-discharge. Since the decomposition of the solvent becomes more severe as the temperature rises, such increase in charge transfer resistance and self-discharge are further promoted in a high temperature environment.
【００３０】一方、表面がフッ素化処理されたリチウム
遷移金属複合酸化物粒子では、表面の酸素がフッ素で置
換されている。図１に、一例としてＴｒｉ−ｎ−ｂｕｔ
ｙｌａｍｍｏｎｉｕｍ Ｂｉｆｌｕｏｒｉｄｅでフッ素
化処理されたリチウム遷移金属複合酸化物粒子１の表面
を模式的に示すが、この化合物でリチウム遷移金属複合
酸化物粒子１を処理すると、このようにＯＨ基がフッ素
で置換される。この置換されたフッ素は酸素に比べて電
気陰性度が大きく、遷移金属元素と強く結合する。した
がって、非水溶媒に対して求核的に働き難く、溶媒の分
解を生ずる可能性も極めて低い。したがって、このよう
に表面がフッ素化処理されたリチウム遷移金属複合酸化
物を正極材料として用いると、電池を高温環境下で保存
したり、高い充電電圧で充放電を行った場合でも、高容
量が維持されるとともに自己放電が抑えられることにな
る。On the other hand, in the surface-fluorinated lithium transition metal composite oxide particles, oxygen on the surface is replaced with fluorine. In FIG. 1, as an example, Tri-n-but
The surface of the lithium-transition metal composite oxide particles 1 fluorinated with ylammonium Bifluoride is schematically shown. When the lithium-transition metal composite oxide particles 1 are treated with this compound, the OH groups are substituted with fluorine in this way. It The substituted fluorine has a higher electronegativity than oxygen and strongly bonds with the transition metal element. Therefore, it is difficult for the non-aqueous solvent to work nucleophilically, and the possibility of solvent decomposition is extremely low. Therefore, when the lithium transition metal composite oxide whose surface is fluorinated is used as the positive electrode material, high capacity is obtained even when the battery is stored in a high temperature environment or charged / discharged at a high charging voltage. It is maintained and self-discharge is suppressed.
【００３１】[0031]
【実施例】以下、本発明の好適な実施例について実験結
果に基づいて説明する。EXAMPLES Preferred examples of the present invention will be described below based on experimental results.
【００３２】実施例１ まず、以下のようにして正極電極を作製した。 Example 1 First, a positive electrode was prepared as follows.
【００３３】Ｔｅｔｒａ−ｎ−ｂｕｔｙｌａｍｍｏｎｉ
ｕｍ Ｆｌｕｏｒｉｄｅ〔（Ｃ4Ｈ9）4ＮＦ〕をテトラ
ヒドロフラン（ＴＨＦ）に溶解してフッ素化合物溶液を
調製した。そして、リチウム遷移金属複合酸化物である
ＬｉＮｉＯ2粒子を、このフッ素化合物溶液に１５分間
浸漬することでフッ素化処理を施した。Tetra-n-butylammoni
um Fluoride [(C 4 H 9 ) 4 NF] was dissolved in tetrahydrofuran (THF) to prepare a fluorine compound solution. Then, the LiNiO 2 particles, which are the lithium-transition metal composite oxide, were immersed in this fluorine compound solution for 15 minutes to be fluorinated.
【００３４】次いで、このフッ素化処理が施されたＬｉ
ＮｉＯ2粒子９０重量部を、速やかにグラファイト７重
量部、フッ素系高分子バインダー３重量部と合わせ、溶
媒となるジメチルホルムアミド（ＤＭＦ）を加えて混合
した。そして、この混合物からＤＭＦを完全に揮発除去
させた後、約６０ｍｇを秤り取り、表面積約２ｃｍ2の
円盤状に加圧成形することで正極電極を作製した。Next, this fluorinated Li was treated.
90 parts by weight of NiO 2 particles were immediately combined with 7 parts by weight of graphite and 3 parts by weight of a fluoropolymer binder, and dimethylformamide (DMF) as a solvent was added and mixed. Then, after DMF was completely volatilized and removed from this mixture, about 60 mg was weighed and pressure-molded into a disk shape having a surface area of about 2 cm 2 to produce a positive electrode.
【００３５】一方、負極電極は、Ｌｉ金属板を表面積約
２ｃｍ2の円盤状に打ち抜くことで作製した。なお、こ
の負極電極は、Ｌｉ量が正極の最大充電能力の数１００
倍であり、正極の電気化学的性能を制限するものではな
い。On the other hand, the negative electrode was prepared by punching a Li metal plate into a disk shape having a surface area of about 2 cm 2 . Note that this negative electrode has a Li content of several 100 times the maximum charging capacity of the positive electrode.
And does not limit the electrochemical performance of the positive electrode.
【００３６】以上のようにして作製された正極電極、負
極電極をそれぞれ正極缶、負極缶に収容した。そして、
この電極がそれぞれ収容された正極缶、負極缶を、電極
同士が対向するようにセパレータを介して積層するとと
もにＬｉＰＦ6をＰＣ（ｐｒｏｐｙｌｅｎｅ ｃａｒｂ
ｏｎａｔｅ）に溶解した電解液を含浸させ、缶外周縁部
をかしめ密閉することで電池を作製した。The positive electrode and the negative electrode manufactured as described above were housed in a positive electrode can and a negative electrode can, respectively. And
A positive electrode can and a negative electrode can, in which the electrodes are housed, are laminated via a separator so that the electrodes face each other, and LiPF 6 is attached to the PC (propyrene carb).
Onate) was impregnated with the dissolved electrolytic solution, and the outer peripheral edge of the can was caulked and sealed to produce a battery.
【００３７】実施例２ 正極電極を作製するに際して、ＬｉＮｉＯ2粒の代わり
にＬｉＮｉ0.8Ｃｏ0.2Ｏ2粒をリチウム遷移金属複合酸
化物粒子として用いたこと以外は実施例１と同様にして
電池を作製した。 Example 2 A battery was prepared in the same manner as in Example 1 except that LiNi 0.8 Co 0.2 O 2 particles were used as lithium transition metal composite oxide particles instead of LiNiO 2 particles when preparing the positive electrode. did.
【００３８】実施例３ 正極電極を作製するに際して、ＬｉＮｉＯ2粒の代わり
にＬｉＭｎ2Ｏ4をリチウム遷移金属複合酸化物粒子とし
て用いたこと以外は実施例１と同様にして電池を作製し
た。 Example 3 A battery was manufactured in the same manner as in Example 1 except that LiMn 2 O 4 was used as the lithium transition metal composite oxide particles instead of the LiNiO 2 particles when manufacturing the positive electrode.
【００３９】実施例４ 正極電極を作製するに際して、Ｔｅｔｒａ−ｎ−ｂｕｔ
ｙｌａｍｍｏｎｉｕｍＦｌｕｏｒｉｄｅの代わりにＴｒ
ｉ−ｎ−ｂｕｔｙｌａｍｍｏｎｉｕｍ Ｂｉｆｌｕｏｒ
ｉｄｅ〔（Ｃ4Ｈ9）3ＮＨＦ〕を用いてフッ素化処理を
行ったこと以外は実施例１と同様にして電池を作製し
た。 Example 4 In producing a positive electrode, Tetra-n-but
Tr instead of ylammoniumFluoride
in-butylammonium Bifluor
A battery was produced in the same manner as in Example 1 except that the fluorination treatment was carried out using ide [(C 4 H 9 ) 3 NHF].
【００４０】実施例５ 正極電極を作製するに際して、ＬｉＮｉＯ2粒の代わり
にＬｉＮｉ0.8Ｃｏ2Ｏ2粒をリチウム遷移金属複合酸化
物粒子として用いるとともにＴｅｔｒａ−ｎ−ｂｕｔｙ
ｌａｍｍｏｎｉｕｍ Ｆｌｕｏｒｉｄｅの代わりにＴｒ
ｉ−ｎ−ｂｕｔｙｌａｍｍｏｎｉｕｍ Ｂｉｆｌｕｏｒ
ｉｄｅを用いてフッ素化処理を行ったこと以外は実施例
１と同様にして電池を作製した。 Example 5 In producing a positive electrode, LiNi 0.8 Co 2 O 2 particles were used as lithium transition metal composite oxide particles instead of LiNiO 2 particles, and Tetra-n-buty was used.
Tr instead of lammonium Fluoride
in-butylammonium Bifluor
A battery was produced in the same manner as in Example 1 except that the fluorination treatment was performed using ide.
【００４１】実施例６ 正極電極を作製するに際して、ＬｉＮｉＯ2粒の代わり
にＬｉＭｎ2Ｏ4粒をリチウム遷移金属複合酸化物粒子と
して用いるとともにＴｅｔｒａ−ｎ−ｂｕｔｙｌａｍｍ
ｏｎｉｕｍ Ｆｌｕｏｒｉｄｅの代わりにＴｒｉ−ｎ−
ｂｕｔｙｌａｍｍｏｎｉｕｍ Ｂｉｆｌｕｏｒｉｄｅを
用いてフッ素化処理を行ったこと以外は実施例１と同様
にして電池を作製した。 Example 6 In producing a positive electrode, LiMn 2 O 4 particles were used as lithium transition metal composite oxide particles instead of LiNiO 2 particles, and Tetra-n-butylamm was used.
Tri-n- instead of onium Fluoride
A battery was produced in the same manner as in Example 1 except that the fluorination treatment was performed using butylammonium Bifluoride.
【００４２】比較例１ 正極電極を作製するに際して、ＬｉＮｉＯ2粒にフッ素
化処理を行わなかったこと以外は実施例１と同様にして
電池を作製した。 Comparative Example 1 A battery was manufactured in the same manner as in Example 1 except that the LiNiO 2 particles were not fluorinated when the positive electrode was manufactured.
【００４３】比較例２ 正極電極を作製するに際して、ＬｉＮｉ0.8Ｃｏ0.2Ｏ2
粒にフッ素化処理を行わなかったこと以外は実施例２と
同様にして電池を作製した。 Comparative Example 2 In producing a positive electrode, LiNi 0.8 Co 0.2 O 2
A battery was prepared in the same manner as in Example 2 except that the particles were not fluorinated.
【００４４】比較例３ 正極電極を作製するに際して、ＬｉＭｎ2Ｏ4粒にフッ素
化処理を行わなかったこと以外は実施例３と同様にして
電池を作製した。 Comparative Example 3 A battery was manufactured in the same manner as in Example 3 except that the LiMn 2 O 4 grains were not fluorinated when the positive electrode was manufactured.
【００４５】以上のようにして作製された電池につい
て、充放電電流密度０．５ｍＡ／ｃｍ2なる条件で充放
電サイクルを２サイクル行った。そして、さらに３サイ
クル目の充電を４．２Ｖまで行い、この充電状態で、一
旦、温度６０℃下、４５時間放置し、３サイクル目の放
電を行った。そして、以下の式に基づいて自己放電率を
算出した。その結果を表１に示す。The battery manufactured as described above was subjected to two charge / discharge cycles under the condition that the charge / discharge current density was 0.5 mA / cm 2 . Then, the charging in the third cycle was further performed up to 4.2V, and in this charged state, the temperature was once kept at 60 ° C. for 45 hours, and the discharging in the third cycle was performed. Then, the self-discharge rate was calculated based on the following formula. Table 1 shows the results.
【００４６】自己放電率（％）＝｛１−（３ｒｄ−Ｃ）
×（２ｎｄ−ｅｆｆ）／（３ｒｄ−Ｄ）｝×１００ ３ｒｄ−Ｃ：放置直前の充電容量（３サイクル目の充電
容量） ２ｎｄ−ｅｆｆ：２サイクル目の充放電効率 ３ｒｄ−Ｄ：放置直後の放電容量（３サイクル目の放電
容量）Self-discharge rate (%) = {1- (3rd-C)
× (2nd-eff) / (3rd-D)} × 100 3rd-C: Charge capacity immediately before leaving (charge capacity at the third cycle) 2nd-eff: Charge / discharge efficiency at the second cycle 3rd-D: Right after leaving Discharge capacity (3rd cycle discharge capacity)
【００４７】[0047]
【表１】 [Table 1]
【００４８】表１に示すように、リチウム遷移金属複合
酸化物粒子にフッ素化処理を施した実施例１〜実施例６
の電池は、リチウム遷移金属複合酸化物粒子にフッ素化
処理を施していない比較例１〜比較例３の電池にくらべ
て自己放電率が小さい値になっている。As shown in Table 1, Examples 1 to 6 in which lithium transition metal composite oxide particles were fluorinated
The battery of (1) has a smaller self-discharge rate than the batteries of Comparative Examples 1 to 3 in which the lithium-transition metal composite oxide particles are not fluorinated.
【００４９】このことから、正極電極にフッ素化処理を
施したリチウム遷移金属複合酸化物粒子を用いること
は、高い充電電圧で高温環境下に放置したときに生じる
自己放電を防止する上で極めて有効であることがわかっ
た。From the above, it is extremely effective to use fluorinated lithium transition metal composite oxide particles for the positive electrode in order to prevent self-discharge which occurs when the battery is left in a high temperature environment at a high charging voltage. I found out.
【００５０】[0050]
【発明の効果】以上の説明からも明らかように、本発明
の非水電解液二次電池では、正極材料としてフッ素化処
理したリチウム遷移金属複合酸化物粒子を用いるので、
高い充電電圧で高温環境下に保存した場合にも、電解液
が分解し難く、電解液の分解によって誘発される容量の
減少や自己放電が抑えられる。したがって、製品として
高い信頼性が得られる。As is clear from the above description, since the non-aqueous electrolyte secondary battery of the present invention uses the fluorinated lithium transition metal composite oxide particles as the positive electrode material,
Even when stored in a high temperature environment with a high charging voltage, the electrolyte solution is difficult to decompose, and the decrease in capacity and self-discharge induced by the decomposition of the electrolyte solution can be suppressed. Therefore, high reliability can be obtained as a product.
【図１】リチウム遷移金属複合酸化物表面がフッ素化処
理された様子を示す模式図である。FIG. 1 is a schematic diagram showing a state where a surface of a lithium-transition metal composite oxide is fluorinated.
Claims (5)
含有する正極と、リチウムをドープ・脱ドープできる炭
素材料、リチウム金属またはリチウム合金のいずれかを
含有する負極と、リチウム塩を非水溶媒に溶解してなる
非水電解液を有してなる非水電解液二次電池において、 上記複合酸化物粒子は、表面がフッ素化処理されている
ことを特徴とする非水電解液二次電池。1. A positive electrode containing composite oxide particles of lithium and a transition metal, a carbon material capable of doping / dedoping lithium, a negative electrode containing either lithium metal or a lithium alloy, and a lithium salt in a non-aqueous solvent. In a non-aqueous electrolyte secondary battery having a non-aqueous electrolyte dissolved therein, the composite oxide particles are fluorinated on the surface thereof. .
を含むことを特徴とする請求項１記載の非水電解液二次
電池。2. The non-aqueous electrolyte secondary battery according to claim 1, wherein the transition metal of the composite oxide particles contains nickel.
を含むことを特徴とする請求項２記載の非水電解液二次
電池。3. The non-aqueous electrolyte secondary battery according to claim 2, wherein the transition metal of the composite oxide particles contains cobalt.
を含むことを特徴とする請求項１記載の非水電解液二次
電池。4. The non-aqueous electrolyte secondary battery according to claim 1, wherein the transition metal of the composite oxide particles contains manganese.
（但し、Ｒ1，Ｒ2，Ｒ3，Ｒ4はＨまたは炭素数が１〜４
のアルキル基である）で示されるフッ素化合物によって
表面がフッ素化処理されていることを特徴とする請求項
１記載の非水電解液二次電池。5. The composite oxide particles are R 1 R 2 R 3 R 4 NF.
(However, R 1 , R 2 , R 3 , and R 4 are H or have 1 to 4 carbon atoms.
2. The non-aqueous electrolyte secondary battery according to claim 1, wherein the surface is fluorinated by a fluorine compound represented by the formula (1).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7017631A JPH08213014A (en) | 1995-02-06 | 1995-02-06 | Nonaqueous electrolyte secondary battery |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7017631A JPH08213014A (en) | 1995-02-06 | 1995-02-06 | Nonaqueous electrolyte secondary battery |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH08213014A true JPH08213014A (en) | 1996-08-20 |
Family
ID=11949220
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7017631A Pending JPH08213014A (en) | 1995-02-06 | 1995-02-06 | Nonaqueous electrolyte secondary battery |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH08213014A (en) |
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| WO2004040676A1 (en) * | 2002-11-01 | 2004-05-13 | Sanyo Electric Co., Ltd. | Nonaqueous electrolyte secondary battery |
| JP2004192896A (en) * | 2002-12-10 | 2004-07-08 | Sony Corp | Cathode active substance, its manufacturing method and nonaqueous electrolyte secondary battery |
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1995
- 1995-02-06 JP JP7017631A patent/JPH08213014A/en active Pending
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| JP2004192896A (en) * | 2002-12-10 | 2004-07-08 | Sony Corp | Cathode active substance, its manufacturing method and nonaqueous electrolyte secondary battery |
| US8057935B2 (en) | 2005-11-02 | 2011-11-15 | Toyo Tanso Co., Ltd. | Lithium ion rechargeable battery |
| WO2007052440A1 (en) | 2005-11-02 | 2007-05-10 | Toyo Tanso Co., Ltd. | Lithium ion rechargeable battery |
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