JPH0521065A - Lithium secondary battery - Google Patents
Lithium secondary batteryInfo
- Publication number
- JPH0521065A JPH0521065A JP3171393A JP17139391A JPH0521065A JP H0521065 A JPH0521065 A JP H0521065A JP 3171393 A JP3171393 A JP 3171393A JP 17139391 A JP17139391 A JP 17139391A JP H0521065 A JPH0521065 A JP H0521065A
- Authority
- JP
- Japan
- Prior art keywords
- lithium
- negative electrode
- secondary battery
- lithium secondary
- carbonaceous 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.)
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Classifications
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- 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
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- Carbon And Carbon Compounds (AREA)
- Secondary Cells (AREA)
- Battery Electrode And Active Subsutance (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、リチウム二次電池に関
し、特に負極を改良したリチウム二次電池に係わる。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lithium secondary battery, and more particularly to a lithium secondary battery having an improved negative electrode.
【０００２】[0002]
【従来の技術】近年、負極活物質としてリチウムを用い
た非水電解液電池は高エネルギ―密度電池として注目さ
れており、正極活物質に二酸化マンガン（ＭｎＯ2 ）、
フッ化炭素［（ＣＦn ）］、塩化チオニル（ＳＯＣ
ｌ2 ）等を用いた一次電池は既に電卓、時計の電源やメ
モリのバックアップ電池として多用されている。更に、
近年、ＶＴＲ、通信機器等の各種の電子機器の小形、軽
量化に伴い、それらの電源として高エネルギ―密度の二
次電池の要求が高まり、リチウムを負極活物質とするリ
チウム二次電池の研究が活発に行われている。2. Description of the Related Art In recent years, non-aqueous electrolyte batteries using lithium as a negative electrode active material have been attracting attention as high energy density batteries, and manganese dioxide (MnO 2 ) has been used as a positive electrode active material.
Fluorocarbon [(CF n )], thionyl chloride (SOC
The primary battery using l 2 ) or the like is already widely used as a power source for calculators, watches, and backup batteries for memories. Furthermore,
With the recent miniaturization and weight reduction of various electronic devices such as VTRs and communication devices, the demand for high energy density secondary batteries as their power sources has increased, and research on lithium secondary batteries using lithium as a negative electrode active material. Is actively carried out.
【０００３】リチウム二次電池は、負極にリチウムを用
い、リチウムイオン伝導性電解質として炭酸プロピレン
（ＰＣ）、1,2-ジメトキシエタン（ＤＭＥ）、γ−ブチ
ロラクトン（γ−ＢＬ）、テトラヒドロフラン（ＴＨ
Ｆ）などの非水溶媒中にＬｉＣｌＯ4 、ＬｉＢＦ4 、Ｌ
ｉＡｓＦ6 、ＬｉＰＦ6 等のリチウム塩を溶解した非水
電解液やリチウムイオン伝導性固体電解質から構成さ
れ、正極活物質としては主にＴｉＳ2 、ＭｏＳ2 、Ｖ2
Ｏ5 、Ｖ6 Ｏ13等のリチウムとの間でトポケミカル反応
する化合物が研究されている。Lithium secondary batteries use lithium as a negative electrode, and as a lithium ion conductive electrolyte, propylene carbonate (PC), 1,2-dimethoxyethane (DME), γ-butyrolactone (γ-BL), tetrahydrofuran (TH).
F) in a non-aqueous solvent such as LiClO 4 , LiBF 4 , L
It is composed of a non-aqueous electrolytic solution in which a lithium salt such as iAsF 6 , LiPF 6 or the like is dissolved or a lithium ion conductive solid electrolyte, and the positive electrode active material is mainly TiS 2 , MoS 2 , V 2
Compounds that undergo a topochemical reaction with lithium such as O 5 and V 6 O 13 have been studied.
【０００４】しかしながら、上述した二次電池は現在、
未だ実用化されていない。この主な理由は、充放電効率
が低く、しかも充放電回数（サイクル）寿命が短いため
である。この原因は、負極リチウムと非水電解液との反
応によるリチウムの劣化によるところが大きいと考えら
れている。即ち、放電時にリチウムイオンとして非水電
解液中に溶解したリチウムは充電時に析出する際に溶媒
と反応し、その表面が一部不活性化される。このため、
充放電を繰返していくと、デンドライト状（樹枝状）の
リチウムが発生したり、小球状に析出したりリチウムが
集電体より脱離するなどの現象が生じる。However, the secondary battery described above is currently
It has not been put to practical use yet. The main reason for this is that the charge / discharge efficiency is low and the charge / discharge cycle (cycle) life is short. It is considered that this is largely due to the deterioration of lithium due to the reaction between the negative electrode lithium and the non-aqueous electrolyte. That is, the lithium dissolved in the non-aqueous electrolyte solution as lithium ions at the time of discharging reacts with the solvent at the time of depositing at the time of charging, and the surface thereof is partially inactivated. For this reason,
When charging and discharging are repeated, dendrite-like (dendritic) lithium is generated, small spheres are deposited, and lithium is desorbed from the current collector.
【０００５】このようなことから、リチウム二次電池に
組込まれる負極としてリチウムを吸蔵・放出する炭素質
物やカルコゲン化合物が検討されている。前記炭素質物
としては、例えばコークス、樹脂焼成体、炭素繊維、熱
分解気相炭素体等を用いることによって、リチウムと非
水電解液との反応やデンドライト析出による負極劣化を
改善することが提案されている。しかしながら、かかる
負極はリチウムイオンの吸蔵・放出量が小さいため、負
極比容量（ｍＡｈ／ｃｍ3 ）が小さく、しかもリチウム
イオンの吸蔵量を大きくする（充電容量を大きくする）
と、例えば炭素質物の構造が劣化したり非水電解液中の
溶媒を分解する。更に、充電電流密度を高くすると、リ
チウムイオンの吸蔵量が低下し、リチウム金属が析出す
る問題がある。これは、リチウムイオンを吸蔵する電位
が０Ｖ（ＶＳ、Ｌｉ／Ｌｉ+ ）以下になるためである。
その結果、前記負極を組み込んだリチウム二次電池はサ
イクル寿命を向上させることが困難となる問題があっ
た。Under these circumstances, carbonaceous materials and chalcogen compounds which occlude and release lithium have been investigated as negative electrodes incorporated in lithium secondary batteries. As the carbonaceous material, for example, by using coke, a resin fired body, carbon fiber, a pyrolysis vapor-phase carbon body, or the like, it is proposed to improve the reaction between lithium and the non-aqueous electrolyte and the deterioration of the negative electrode due to dendrite precipitation. ing. However, since such a negative electrode has a small amount of lithium ion absorption / desorption, it has a negative electrode specific capacity (mAh / cm 3 ) Is small, and the lithium ion storage amount is large (the charging capacity is large).
Then, for example, the structure of the carbonaceous material is deteriorated or the solvent in the non-aqueous electrolyte is decomposed. Furthermore, when the charging current density is increased, the amount of lithium ions stored decreases, and there is a problem that lithium metal is deposited. This is because the potential for occluding lithium ions is 0 V (VS, Li / Li + This is because it becomes the following.
As a result, the lithium secondary battery incorporating the negative electrode has a problem that it is difficult to improve the cycle life.
【０００６】一方、リチウムイオンが挿入・脱離される
カルコゲン化合物の中で、起電力の低いＷＯ2 、ＭｏＯ
2 、ＦｅＯＣｌ、ＮｂＳｅ3 等を負極として用いること
が提案され、特にＷＯ2 ／ＬｉＣｏＯ2 の負極を備えた
電池は平均電圧が３．２ＶとなることがＪ．Ｅｌｅｃｔ
ｒｏｃｈｅｍ．Ｓｏｃ．，１３４、６３８（１９８７）
において発表されている。On the other hand, among chalcogen compounds in which lithium ions are inserted / desorbed, WO 2 and MoO having low electromotive force are used.
It has been proposed to use 2 , 2 , FeOCl, NbSe 3 or the like as a negative electrode. Particularly, a battery provided with a WO 2 / LiCoO 2 negative electrode has an average voltage of 3.2V. Elect
rochem. Soc. , 134, 638 (1987)
Has been announced in.
【０００７】しかしながら、前記カルコゲン化合物から
なる負極はリチウムイオンの挿入時（充電時）に電解液
の分解が起き易い、充放電効率が低い、導電性が低い等
の問題がある。このため、前記負極を組み込んだリチウ
ム二次電池は容量および寿命の点で十分満足するもので
はなかった。なお、前記カルコゲン化合物からなる負極
の導電性を改善するためにグラファイト、アセチレンブ
ラックなどのカーボンを導電剤として配合することが試
みられているが、前記カルコゲン化合物は前記カーボン
上で電解液を還元分解するという問題があった。However, the negative electrode made of the above chalcogen compound has problems that the electrolytic solution is easily decomposed when lithium ions are inserted (at the time of charging), charge / discharge efficiency is low, and conductivity is low. For this reason, the lithium secondary battery incorporating the negative electrode was not sufficiently satisfactory in terms of capacity and life. In order to improve the conductivity of the negative electrode made of the chalcogen compound, it has been attempted to blend carbon such as graphite or acetylene black as a conductive agent, but the chalcogen compound is reductively decomposed on the carbon by electrolytic solution. There was a problem of doing.
【０００８】[0008]
【発明が解決しようとする課題】本発明は、上記従来の
問題点を解決するためになされたもので、高容量でサイ
クル寿命の優れたリチウム二次電池を提供しようとする
ものである。SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide a lithium secondary battery having a high capacity and an excellent cycle life.
【０００９】[0009]
【課題を解決するための手段】本発明に係わるリチウム
二次電池は、容器内に正極、負極およびリチウムイオン
伝導性電解質を収納したリチウム二次電池において、A lithium secondary battery according to the present invention is a lithium secondary battery in which a positive electrode, a negative electrode and a lithium ion conductive electrolyte are housed in a container,
【００１０】前記負極は（ａ）リチウムイオンを挿入・
脱離する反応が平均電位２Ｖ（ＶＳ、Ｌｉ／Ｌｉ+ ）以
下であるカルコゲン化合物または同性質を有するリチウ
ムイオン含有カルコゲン化合物と（ｂ）リチウムイオン
を吸蔵・放出することが可能な炭素質物との混合物から
なることを特徴とするものである。The negative electrode has (a) lithium ions inserted therein.
The desorption reaction has an average potential of 2 V (VS, Li / Li + ) The following chalcogen compound or a mixture of a chalcogen compound containing lithium ions having the same properties and (b) a carbonaceous material capable of inserting and extracting lithium ions.
【００１１】前記正極は、種々の酸化物、例えば二酸化
マンガン、リチウムマンガン複合酸化物、リチウム含有
ニッケル酸化物、リチウム含有コバルト酸化物、リチウ
ム含有ニッケルコバルト酸化物、リチウムを含む非晶質
五酸化バナジウムや、二硫化チタン、二硫化モリブデン
などの２Ｖ（ＶＳ、Ｌｉ／Ｌｉ+ ）以上の起電力を有す
るカルコゲン化合物等を挙げることができる。中でも、
起電力の高いリチウムコバルト酸化物（ＬｉＣｏＯ2 ）
を用いることが好ましい。The positive electrode is made of various oxides such as manganese dioxide, lithium manganese composite oxide, lithium-containing nickel oxide, lithium-containing cobalt oxide, lithium-containing nickel cobalt oxide, and lithium-containing amorphous vanadium pentoxide. Or 2V (VS, Li / Li + such as titanium disulfide and molybdenum disulfide) ) The chalcogen compound etc. which have the above electromotive force can be mentioned. Above all,
High electromotive force lithium cobalt oxide (LiCoO 2 )
Is preferably used.
【００１２】前記負極を構成する（ａ）成分である前記
カルコゲン化合物またはリチウム含有カルコゲン化合物
としてはリチウムイオンを平均電位２Ｖ（ＶＳ、Ｌｉ／
Ｌｉ+ ）以下で挿入・脱離反応を起こすＷＯ2 、ＭｏＳ
2 、ＶＳｅ2 、ＶＳ2 、ＬｉＶＳｅ2 、ＬｉＴｉＳ2 、
Ｆｅ2 Ｏ3 等を挙げることができる。中でもＷＯ2 は電
池電圧をより高めることができるために有用である。As the chalcogen compound or the lithium-containing chalcogen compound, which is the component (a) constituting the negative electrode, lithium ions are charged at an average potential of 2 V (VS, Li /
Li + ) WO 2 , MoS that causes insertion / desorption reactions below
2 , VSe 2 , VS 2 , LiVSe 2 , LiTiS 2 ,
Fe 2 O 3 and the like can be mentioned. Among them, WO 2 is useful because it can further increase the battery voltage.
【００１３】前記負極を構成する（ｂ）成分である前記
炭素質物は、黒鉛構造と乱層構造からなり、前記黒鉛構
造を規定するＸ線回折により得られる（００２）面の面
間隔（ｄ002 ）が０．３４０ｎｍ以上、Ｃ軸方向の結晶
子の大きさ（Ｌc ）が２０ｎｍ以下であることが望まし
い。このようなｄ002 及びＬc の値が、前記範囲を逸脱
すると前記炭素質物を（ｂ）成分として含む負極の０．
５Ｖ（ＶＳ、Ｌｉ／Ｌｉ+ ）以上の電位におけるリチウ
ムイオン吸蔵・放出量の減少、黒鉛構造の劣化、非水電
解液中の溶媒の還元分解によるガス発生等を招き、二次
電池の容量減少とサイクル寿命の低下を生じる恐れがあ
る。より好ましい前記ｄ002 及びＬc は、それぞれ０．
３４５〜０．３７０ｎｍ、１〜１０ｎｍの範囲である。The carbonaceous material, which is the component (b) constituting the negative electrode, has a graphite structure and a turbostratic structure, and the interplanar spacing (d 002 ) of the (002) plane obtained by X-ray diffraction that defines the graphite structure. ) Is 0.340 nm or more and the crystallite size (Lc) in the C-axis direction is 20 nm or less. If the values of d 002 and Lc deviate from the above ranges, the negative electrode of the negative electrode containing the carbonaceous material as the component (b) may be 0.
5V (VS, Li / Li + ) At the above potentials, the amount of lithium ion absorption / desorption may decrease, the graphite structure may deteriorate, gas may be generated due to the reductive decomposition of the solvent in the non-aqueous electrolyte, and the capacity and cycle life of the secondary battery may decrease. There is. More preferable d 002 and L c are each 0.
The range is 345 to 0.370 nm and 1 to 10 nm.
【００１４】前記炭素質物を構成する黒鉛構造と乱層構
造の比率の尺度としては、アルゴンレーザ（波長；５１
４．５ｎｍ）を光源として測定された炭素質物のラマン
スペクトルがある。測定されるラマンスペクトルは、１
３６０cm-1付近に現れる乱層構造に由来するピークと、
１５８０cm-1付近に現れる黒鉛構造に由来するピークと
が存在し、そのピーク強度比（例えば乱層構造に由来す
るラマン強度をＲ1 、黒鉛構造に由来するラマン強度を
Ｒ2 とした場合の強度比Ｒ1 ／Ｒ2 ）又は面積比を用い
ることが有効である。前記負極を構成する（ｂ）成分に
適する炭素質物における黒鉛構造と乱層構造の比率は、
前記Ｒ1 ／Ｒ2 が０．８より大きくなるように設定する
ことが望ましい。かかる強度比を０．８以下にすると、
負極の０．５Ｖ（ＶＳ、Ｌｉ／Ｌｉ+ ）以上の電位にお
けるリチウムイオン吸蔵・放出量の減少を伴う。より好
ましい強度比（Ｒ1 ／Ｒ2 ）は、１．０〜１．７の範囲
である。As a measure of the ratio of the graphite structure and the turbostratic structure constituting the carbonaceous material, an argon laser (wavelength: 51) is used.
There is a Raman spectrum of the carbonaceous material measured by using (4.5 nm) as a light source. Raman spectrum measured is 1
A peak derived from a turbostratic structure that appears near 360 cm -1 ,
There is a peak derived from a graphite structure appearing around 1580 cm −1 , and the peak intensity ratio (for example, intensity when Raman intensity derived from turbostratic structure is R 1 and Raman intensity derived from graphite structure is R 2) It is effective to use the ratio R 1 / R 2 ) or the area ratio. The ratio of the graphite structure to the turbostratic structure in the carbonaceous material suitable for the component (b) constituting the negative electrode is
It is desirable to set R 1 / R 2 to be larger than 0.8. If the intensity ratio is 0.8 or less,
0.5V of negative electrode (VS, Li / Li + ) With decrease in the amount of lithium ion storage / release at the above potential. A more preferable strength ratio (R 1 / R 2 ) is in the range of 1.0 to 1.7.
【００１５】前記炭素質物中の未黒鉛化による残留水素
の比率は、水素／炭素の原子比（Ｈ／Ｃ）で規定され
る。前記負極材として適する炭素質物は、前記Ｈ／Ｃが
０．１５以下であることが望ましい。かかるＨ／Ｃが
０．１５を越えると、負極のリチウムイオン吸蔵・放出
量を増大させることが困難となるばかりか、充放電効率
も低下する恐れがある。より好ましいＨ／Ｃは、０．０
４以下である。前記炭素質物としては、上述した性質を
有するものであれば、コークス、ピッチ系炭素繊維、球
状炭素質物、熱分解気相炭素体などを用いることができ
る。The ratio of residual hydrogen due to non-graphitization in the carbonaceous material is defined by the hydrogen / carbon atomic ratio (H / C). The H / C of the carbonaceous material suitable as the negative electrode material is preferably 0.15 or less. When the H / C exceeds 0.15, it becomes difficult not only to increase the amount of lithium ion stored / released in the negative electrode, but also the charge / discharge efficiency may decrease. More preferable H / C is 0.0
It is 4 or less. As the carbonaceous material, coke, pitch-based carbon fiber, spherical carbonaceous material, pyrolytic vapor-phase carbonaceous material and the like can be used as long as they have the above-mentioned properties.
【００１６】前記負極を構成する（ａ）前記カルコゲン
化合物またはリチウムイオン含有カルコゲン化合物と
（ｂ）前記炭素質物の混合比（ｂ／ａ）は、前記負極の
導電率、比容量（ｍＡｈ／ｃｍ3 ）の関係から設定する
ことが望ましく、具体的には重量比率にて０．０４〜
０．５の範囲とすることが好ましい。これは、前記混合
比を０．０４未満にすると負極の抵抗増大と利用率の低
下により容量の低下を招く恐れがあり、一方前記混合比
が０．５を越えると負極充填密度の低下により比容量が
低下する恐れがあるからである。より好ましい前記混合
比（ｂ／ａ）は、０．０７〜０．３５の範囲である。The mixing ratio (b / a) of (a) the chalcogen compound or the lithium ion-containing chalcogen compound and (b) the carbonaceous material constituting the negative electrode is determined by the conductivity and the specific capacity (mAh / cm 3 ) of the negative electrode. It is desirable to set it from the relationship of), and specifically, the weight ratio is 0.04 to
The range of 0.5 is preferable. This is because if the mixing ratio is less than 0.04, the capacity of the negative electrode may increase due to an increase in the resistance of the negative electrode and the utilization ratio may decrease. On the other hand, if the mixing ratio exceeds 0.5, the negative electrode packing density may decrease. This is because the capacity may decrease. The more preferable mixing ratio (b / a) is in the range of 0.07 to 0.35.
【００１７】前記リチウムイオン伝導性電解質として
は、例えばエチレンカーボネート、プロピレンカーボネ
ート、ブチレンカーボネート、γ−ブチロラクトン、ス
ルホラン、アセトニトリル、1,2-ジメトキシエタン、1,
3-ジメトキシプロパン、ジメチルエーテル、テトラヒド
ロフラン、2-メチルテトラヒドロフランから選ばれる少
なくと１種以上からなる非水溶媒に過塩素酸リチウム
（ＬｉＣｌＯ4 ）、六フッ化リン酸リチウム（ＬｉＰＦ
6 ）、ホウフッ化リチウム（ＬｉＢＦ4 ）、六フッ化砒
素リチウム（ＬｉＡｓＦ6 ）、トリフルオロメタンスル
ホン酸リチウム（ＬｉＣＦ3 ＳＯ3 ）などのリチウム塩
（電解質）を溶解した非水電解液を挙げることができ
る。前記電解質の非水溶媒に対する溶解量は、0.5〜 1.
5モル／ｌとすることが望ましい。また、リチウムイオ
ン伝導性の固体電解質を用いることができる。例えば、
高分子化合物にリチウム塩を複合した高分子固体電解質
を挙げることができる。Examples of the lithium ion conductive electrolyte include ethylene carbonate, propylene carbonate, butylene carbonate, γ-butyrolactone, sulfolane, acetonitrile, 1,2-dimethoxyethane, 1,
Lithium perchlorate (LiClO 4 ), lithium hexafluorophosphate (LiPF 4 ) in a non-aqueous solvent consisting of at least one selected from 3-dimethoxypropane, dimethyl ether, tetrahydrofuran and 2-methyltetrahydrofuran.
6 ), lithium borofluoride (LiBF 4 ), lithium hexafluoroarsenide (LiAsF 6 ), lithium trifluoromethanesulfonate (LiCF 3 SO 3 ), and other nonaqueous electrolyte solutions in which a lithium salt (electrolyte) is dissolved. it can. The amount of the electrolyte dissolved in the non-aqueous solvent is 0.5 to 1.
5 mol / l is desirable. Further, a lithium ion conductive solid electrolyte can be used. For example,
A polymer solid electrolyte in which a lithium salt is compounded with a polymer compound can be mentioned.
【００１８】[0018]
【作用】本発明によれば、（ａ）リチウムイオンを挿入
・脱離する反応が平均電位２Ｖ（ＶＳ、Ｌｉ／Ｌｉ+ ）
以下であるカルコゲン化合物または同性質を有するリチ
ウムイオン含有カルコゲン化合物と（ｂ）リチウムイオ
ンを吸蔵・放出することが可能な炭素質物との混合物か
ら負極を構成することによって、前記（ａ）成分のみか
らなる負極に比べて負極の導電性と、充放電容量および
サイクル寿命を増大できる。これは、前記（ｂ）成分で
あるリチウムイオンを吸蔵・放出することが可能な炭素
質物が前記負極と共に容器に収納されるリチウムムイオ
ン伝導性非水電解質の分解を起こさずに負極活物質およ
び導電材として作用するためである。特に、前記炭素質
物として黒鉛構造と乱層構造からなり、黒鉛構造におけ
る（００２）面の面間隔（ｄ002 ）が０．３４０ｎｍ以
上、Ｃ軸方向の結晶子の大きさ（Ｌc ）が２０ｎｍ以下
であり、アルゴンレーザラマンスペクトルにおける１５
８０ｃｍ-1のピーク強度に対する１３６０ｃｍ-1のピー
ク強度比が０．８より大きいものを用いると、リチウム
イオンを吸蔵する容量が０．５Ｖ（ＶＳ、Ｌｉ／Ｌ
ｉ+ ）以上の電位域で増大するため負極容量の増大に寄
与できる。According to the present invention, (a) the reaction of inserting / desorbing lithium ions has an average potential of 2 V (VS, Li / Li + )
By forming the negative electrode from a mixture of the following chalcogen compound or a lithium ion-containing chalcogen compound having the same properties and (b) a carbonaceous material capable of absorbing and releasing lithium ions, the above-mentioned component (a) alone is used. The conductivity, charge / discharge capacity and cycle life of the negative electrode can be increased as compared with the negative electrode. This is because the carbonaceous material capable of inserting and extracting the lithium ions as the component (b) does not cause decomposition of the lithium ion conductive non-aqueous electrolyte housed in the container together with the negative electrode, and the negative electrode active material and the conductive material. This is because it acts as a material. In particular, the carbonaceous material has a graphite structure and a turbostratic structure, the (002) plane spacing (d 002 ) in the graphite structure is 0.340 nm or more, and the crystallite size (Lc) in the C-axis direction is 20 nm or less. And 15 in the argon laser Raman spectrum
When the peak intensity ratio of 1360 cm -1 to the peak intensity of 80 cm -1 is used greater than 0.8, the capacity of occluding lithium ions 0.5V (VS, Li / L
i + ) Since it increases in the above potential range, it can contribute to the increase of the negative electrode capacity.
【００１９】さらに、前記負極を構成する（ａ）前記カ
ルコゲン化合物またはリチウムイオン含有カルコゲン化
合物と（ｂ）前記炭素質物の混合比（ｂ／ａ）を重量比
率にて０．０４〜０．５の範囲とすると、負極の比容量
（ｍＡｈ／ｃｍ3 ）と導電率を最適値に設定でき、充放
電容量を増大できる。Furthermore, the mixing ratio (b / a) of (a) the chalcogen compound or the lithium ion-containing chalcogen compound and (b) the carbonaceous material constituting the negative electrode is 0.04 to 0.5 by weight. When the range is set, the specific capacity of the negative electrode (mAh / cm 3 ) And conductivity can be set to an optimum value, and the charge / discharge capacity can be increased.
【００２０】[0020]
【実施例】以下、本発明を円筒形リチウム二次電池に適
用した例を図１を参照して詳細に説明する。
実施例１EXAMPLE An example in which the present invention is applied to a cylindrical lithium secondary battery will be described in detail below with reference to FIG. Example 1
【００２１】図中の１は、底部に絶縁体２が配置された
有底円筒状のステンレス容器である。この容器１内に
は、電極群３が収納されている。この電極群３は、正極
４、セパレ―タ５及び負極６をこの順序で積層した帯状
物を該負極６が外側に位置するように渦巻き状に巻回し
た構造になっている。Reference numeral 1 in the drawing denotes a cylindrical stainless steel container having a bottom and an insulator 2 arranged on the bottom. The electrode group 3 is housed in the container 1. The electrode group 3 has a structure in which a band-shaped material in which a positive electrode 4, a separator 5 and a negative electrode 6 are laminated in this order is spirally wound so that the negative electrode 6 is located outside.
【００２２】前記正極４は、リチウムコバルト酸化物
（Ｌｉx ＣｏＯ2 ）粉末８０重量％をアセチレンブラッ
ク１５重量％およびポリテトラフルオロエチレン粉末５
重量％と共に混合し、シート化し、エキスパンドメタル
集電体に圧着した形状になっている。前記セパレ―タ５
は、ポリプロピレン性多孔質フィルムから形成されてい
る。The positive electrode 4 comprises 80 wt% lithium cobalt oxide (Li x CoO 2 ) powder, 15 wt% acetylene black and 5 polytetrafluoroethylene powder 5.
It is mixed with wt%, made into a sheet, and pressed into an expanded metal current collector. The separator 5
Is formed of a polypropylene porous film.
【００２３】前記負極６は、ピッチから熱処理、分離さ
れたメソフェーズ小球体を炭素化して得られた平均粒径
が１０μｍの球状炭素質物粒子［（ｂ）成分］１７重量
％とＷＯ2 ［（ａ）成分］８０重量％とエチレンプロピ
レン共重合体３重量％とを混合し、これを集電体として
のニッケル箔に６０ｍｇ／ｃｍ2 の量で塗布したもので
ある。なお、前記炭素質物粒子はＸ線回折による各種の
パラメータがｄ002 ＝０．３５０８ｎｍ、Ｌc＝２．５
０ｎｍで、アルゴンレーザを光源として測定された１３
６０cm-1のラマン強度Ｒ1 と１５８０cm-1のラマン強度
Ｒ2 の比（Ｒ1／Ｒ2 ）が１．１である。また、前記炭
素質物粒子は水素／炭素の原子比が０．００３である。
前記ＷＯ2 と炭素質物の重量比（ａ／ｂ）は、０．２１
２５である。The negative electrode 6 was obtained by carbonizing the mesophase spherules separated by heat treatment from the pitch and carbonizing the spherical carbonaceous material particles [component (b) component] having an average particle size of 10 μm and WO 2 [(a ) Component] 80% by weight and 3% by weight of ethylene-propylene copolymer are mixed, and this is added to a nickel foil as a current collector at 60 mg / cm 2. It was applied in the amount of. The carbonaceous material particles have various parameters by X-ray diffraction of d 002 = 0.3508 nm and Lc = 2.5.
13 measured at 0 nm with an Argon laser as the light source
60cm ratio of the Raman intensity R 2 of the Raman intensity R 1 and 1580 cm -1 of -1 (R 1 / R 2) is 1.1. The carbonaceous material particles have a hydrogen / carbon atomic ratio of 0.003.
The weight ratio (a / b) of WO 2 and the carbonaceous material is 0.21.
25.
【００２４】前記容器１内には、六フッ化リン酸リチウ
ム（ＬｉＰＦ6 ）をエチレンカーボネートとプロピレン
カーボネートと１，２−ジメトキシエタンの混合溶媒
（混合体積比率２５：２５：５０）に１．０モル／ｌ溶
解した組成の電解液が収容されている。前記電極群３上
には、中央部が開口された絶縁紙７が載置されている。
更に、前記容器 1の上部開口部には、絶縁封口板８が該
容器１へのかしめ加工等により液密に設けられており、
かつ該絶縁封口板８の中央には正極端子９が嵌合されて
いる。この正極端子９は、前記電極群３の正極４に正極
リ―ド１０を介して接続されている。なお、電極群３の
負極６は図示しない負極リ―ドを介して負極端子である
前記容器１に接続されている。
実施例２Lithium hexafluorophosphate (LiPF 6 ) was added to the container 1 in a mixed solvent of ethylene carbonate, propylene carbonate and 1,2-dimethoxyethane (mixing volume ratio 25:25:50) at 1.0. An electrolytic solution having a dissolved mol / l composition is contained. On the electrode group 3, an insulating paper 7 having a central opening is placed.
Further, an insulating sealing plate 8 is provided in the upper opening of the container 1 in a liquid-tight manner by caulking the container 1 or the like,
A positive electrode terminal 9 is fitted in the center of the insulating sealing plate 8. The positive electrode terminal 9 is connected to the positive electrode 4 of the electrode group 3 via a positive electrode lead 10. The negative electrode 6 of the electrode group 3 is connected to the container 1, which is a negative electrode terminal, via a negative electrode lead (not shown). Example 2
【００２５】負極を構成する（ｂ）成分である球状炭素
質物粒子としてＸ線回折による各種のパラメータとして
のｄ002 ＝０．３４５２ｎｍ、Ｌc ＝２．５０ｎｍ、前
記Ｒ1 ／Ｒ2 が１．０のものを用いた以外、実施例１と
同構成のリチウム二次電池を組み立てた。
実施例３As spherical carbonaceous material particles which are the component (b) constituting the negative electrode, d 002 = 0.3452 nm, Lc = 2.50 nm as various parameters by X-ray diffraction, and R 1 / R 2 is 1.0. A lithium secondary battery having the same structure as in Example 1 was assembled except that the above-mentioned one was used. Example 3
【００２６】負極を構成する（ｂ）成分である球状炭素
質物粒子としてＸ線回折による各種のパラメータとして
のｄ002 ＝０．３４１０ｎｍ、Ｌc ＝５．００ｎｍ、前
記Ｒ1 ／Ｒ2 が０．７５、水素／炭素の原子比が０．０
０１である平均粒径が２０μｍのものを用いた以外、実
施例１と同構成のリチウム二次電池を組み立てた。
実施例４As spherical carbonaceous material particles which are the component (b) constituting the negative electrode, d 002 = 0.3410 nm, Lc = 5.00 nm as various parameters by X-ray diffraction, and R 1 / R 2 is 0.75. , The hydrogen / carbon atomic ratio is 0.0
A lithium secondary battery having the same structure as in Example 1 was assembled except that the average particle size of No. 01 was 20 μm. Example 4
【００２７】ピッチから熱処理、分離されたメソフェー
ズ小球体を炭素化して得られた平均粒径が１０μｍの球
状炭素質物粒子［（ｂ）成分］２７重量％とＷＯ
2 ［（ａ）成分］７０重量％とエチレンプロピレン共重
合体３重量％とを混合し、これを集電体としてのニッケ
ル箔に４０ｍｇ／ｃｍ2 の量で塗布した負極を用いた以
外、実施例１と同構成のリチウム二次電池を組み立て
た。
実施例５27% by weight of spherical carbonaceous material particles (component (b)) having an average particle diameter of 10 μm obtained by carbonizing mesophase small spheres separated by heat treatment from the pitch and WO
2 [Component (a)] 70% by weight and 3% by weight of ethylene-propylene copolymer were mixed, and 40 mg / cm 2 was added to a nickel foil as a current collector. A lithium secondary battery having the same configuration as in Example 1 was assembled except that the negative electrode coated in the amount of was used. Example 5
【００２８】ピッチから熱処理、分離されたメソフェー
ズ小球体を炭素化して得られた平均粒径が１０μｍの球
状炭素質物粒子［（ｂ）成分］７重量％とＷＯ
2 ［（ａ）成分］９０重量％とエチレンプロピレン共重
合体３重量％とを混合し、これを集電体としてのニッケ
ル箔に７０ｍｇ／ｃｍ2 の量で塗布した負極を用いた以
外、実施例１と同構成のリチウム二次電池を組み立て
た。
比較例１7% by weight of spherical carbonaceous material particles (component (b)) having an average particle size of 10 μm obtained by carbonizing the mesophase spheres separated by heat treatment from the pitch and WO
2 [Component (a)] 90% by weight and 3% by weight of ethylene propylene copolymer were mixed, and this was added to a nickel foil as a current collector at 70 mg / cm 2. A lithium secondary battery having the same configuration as in Example 1 was assembled except that the negative electrode coated in the amount of was used. Comparative Example 1
【００２９】ＷＯ2 ９７重量％とエチレンプロピレン共
重合体３重量％とを混合し、これを集電体としてのニッ
ケル箔に８５ｍｇ／ｃｍ2 の量で塗布した負極を用いた
以外、実施例１と同構成のリチウム二次電池を組み立て
た。
比較例２WO297 wt% and ethylene propylene
3% by weight of the polymer was mixed, and this was used as a current collector.
85 mg / cm on Kell foil2 With the negative electrode applied in the amount of
Other than that, the lithium secondary battery having the same configuration as in Example 1 was assembled.
It was
Comparative example 2
【００３０】メソフェーズ小球体を炭素化した球状炭素
質物粒子９８重量％とエチレンプロピレン共重合体２重
量％とを混合し、これを集電体としてのニッケル箔に１
０ｍｇ／ｃｍ2 の量で塗布した負極を用いた以外、実施
例１と同構成のリチウム二次電池を組み立てた。
比較例３98% by weight of spherical carbonaceous material particles obtained by carbonizing mesophase spherules and 2% by weight of ethylene-propylene copolymer were mixed, and the mixture was used as a nickel foil as a current collector.
0 mg / cm 2 A lithium secondary battery having the same configuration as in Example 1 was assembled except that the negative electrode coated in the amount of was used. Comparative Example 3
【００３１】グラファイト１７重量％とＷＯ2 ８０重量
％とエチレンプロピレン共重合体３重量％とを混合し、
これを集電体としてのニッケル箔に６０ｍｇ／ｃｍ2 の
量で塗布した負極を用いた以外、実施例１と同構成のリ
チウム二次電池を組み立てた。なお、前記グラファイト
はＸ線回折による各種パラメータはｄ002 ＝０．３３８
ｎｍ、Ｌc ＝５０ｎｍ、前記Ｒ1 ／Ｒ2 が０．１であ
る。17% by weight of graphite, 80% by weight of WO 2 and 3% by weight of ethylene-propylene copolymer were mixed,
60 mg / cm 2 of this on a nickel foil as a current collector A lithium secondary battery having the same configuration as in Example 1 was assembled except that the negative electrode coated in the amount of was used. The various parameters of X-ray diffraction of the graphite are d 002 = 0.338.
nm, Lc = 50 nm, and R 1 / R 2 is 0.1.
【００３２】しかして、本実施例１〜５及び比較例１〜
３のリチウム二次電池について充電電流５０ｍＡで３．
４Ｖまで充電し、５０ｍＡの電流で２．０Ｖまで放電す
る充放電（ただし、比較例２の電池では充電電流５０ｍ
Ａで４．２Ｖまで充電し、５０ｍＡの電流で３．０Ｖま
で放電する充放電）を繰り返し行い、各電池の放電容量
とサイクル寿命をそれぞれ測定した。その結果を図２に
示す。Thus, Examples 1 to 5 and Comparative Examples 1 to 1
2. Regarding the lithium secondary battery of No. 3, with a charging current of 50 mA.
Charge and discharge that charges up to 4V and discharges up to 2.0V at a current of 50mA (however, in the battery of Comparative Example 2, charging current 50m
The battery was repeatedly charged with A to 4.2 V and discharged with a current of 50 mA to 3.0 V), and the discharge capacity and cycle life of each battery were measured. The result is shown in FIG.
【００３３】図２から明らかなように本実施例１〜５の
リチウム二次電池では、比較例１〜３の電池に比べて容
量が増大し、かつサイクル寿命が格段に向上することが
わかる。As is apparent from FIG. 2, the lithium secondary batteries of Examples 1 to 5 have a larger capacity and a significantly longer cycle life than the batteries of Comparative Examples 1 to 3.
【００３４】[0034]
【発明の効果】以上詳述した如く、本発明によれば高容
量でサイクル寿命の優れたリチウム二次電池を提供でき
る。As described in detail above, according to the present invention, a lithium secondary battery having a high capacity and an excellent cycle life can be provided.
【図１】本発明の実施例１における円筒形リチウム二次
電池を示す部分断面図。FIG. 1 is a partial cross-sectional view showing a cylindrical lithium secondary battery in Example 1 of the present invention.
【図２】実施例１〜５及び比較例１〜３のリチウム二次
電池における充放電サイクルと放電容量との関係を示す
特性図。FIG. 2 is a characteristic diagram showing the relationship between the charge / discharge cycle and the discharge capacity in the lithium secondary batteries of Examples 1-5 and Comparative Examples 1-3.
１…ステンレス容器、３…電極群、４…正極、５…セパ
レ―タ、６…負極、８…封口板、９…正極端子。DESCRIPTION OF SYMBOLS 1 ... Stainless steel container, 3 ... Electrode group, 4 ... Positive electrode, 5 ... Separator, 6 ... Negative electrode, 8 ... Sealing plate, 9 ... Positive electrode terminal.
Claims (2)
ン伝導性電解質を収納したリチウム二次電池において、 前記負極は（ａ）リチウムイオンを挿入・脱離する反応
が平均電位２Ｖ（ＶＳ、Ｌｉ／Ｌｉ+ ）以下であるカル
コゲン化合物または同性質を有するリチウムイオン含有
カルコゲン化合物と（ｂ）リチウムイオンを吸蔵・放出
することが可能な炭素質物との混合物からなることを特
徴とするリチウム二次電池。1. A lithium secondary battery in which a positive electrode, a negative electrode and a lithium ion conductive electrolyte are housed in a container, wherein the negative electrode has a mean potential of 2 V (VS, Li / Li + ) A lithium secondary battery comprising the following chalcogen compound or a mixture of a lithium ion-containing chalcogen compound having the same properties and (b) a carbonaceous material capable of inserting and extracting lithium ions.
らなり、黒鉛構造における（００２）面の面間隔（ｄ
002 ）が０．３４０ｎｍ以上、Ｃ軸方向の結晶子の大き
さ（Ｌc ）が２０ｎｍ以下であり、アルゴンレーザラマ
ンスペクトルにおける１５８０ｃｍ-1のピーク強度に対
する１３６０ｃｍ-1のピーク強度比が０．８より大きい
ことを特徴とする請求項１記載のリチウム二次電池。2. The carbonaceous material has a graphite structure and a turbostratic structure, and the interplanar spacing (d) of the (002) planes in the graphite structure.
002) is more than 0.340 nm, and the size of the C-axis direction of the crystallite (Lc) is 20nm or less, is greater than 0.8 the peak intensity ratio of 1360 cm -1 to the peak intensity of 1580 cm -1 in the argon laser Raman spectra The lithium secondary battery according to claim 1, wherein:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP03171393A JP3135613B2 (en) | 1991-07-11 | 1991-07-11 | Lithium secondary battery |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP03171393A JP3135613B2 (en) | 1991-07-11 | 1991-07-11 | Lithium secondary battery |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0521065A true JPH0521065A (en) | 1993-01-29 |
| JP3135613B2 JP3135613B2 (en) | 2001-02-19 |
Family
ID=15922332
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP03171393A Expired - Lifetime JP3135613B2 (en) | 1991-07-11 | 1991-07-11 | Lithium secondary battery |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3135613B2 (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0613197A1 (en) * | 1993-02-25 | 1994-08-31 | Kureha Kagaku Kogyo Kabushiki Kaisha | Carbonaceous electrode material for secondary battery |
| US5432029A (en) * | 1993-05-14 | 1995-07-11 | Sharp Kabushiki Kaisha | Lithium secondary battery |
| EP0713256A1 (en) | 1994-10-27 | 1996-05-22 | Sharp Kabushiki Kaisha | Lithium secondary battery and process for preparing negative-electrode active material for use in the same |
| US5591547A (en) * | 1994-07-29 | 1997-01-07 | Sharp Kabushiki Kaisha | Method of manufacturing a negative electrode for lithium secondary battery |
| JP2006032070A (en) * | 2004-07-14 | 2006-02-02 | Kri Inc | Nonaqueous secondary battery |
-
1991
- 1991-07-11 JP JP03171393A patent/JP3135613B2/en not_active Expired - Lifetime
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0613197A1 (en) * | 1993-02-25 | 1994-08-31 | Kureha Kagaku Kogyo Kabushiki Kaisha | Carbonaceous electrode material for secondary battery |
| US5432029A (en) * | 1993-05-14 | 1995-07-11 | Sharp Kabushiki Kaisha | Lithium secondary battery |
| US5591547A (en) * | 1994-07-29 | 1997-01-07 | Sharp Kabushiki Kaisha | Method of manufacturing a negative electrode for lithium secondary battery |
| EP0713256A1 (en) | 1994-10-27 | 1996-05-22 | Sharp Kabushiki Kaisha | Lithium secondary battery and process for preparing negative-electrode active material for use in the same |
| US5576121A (en) * | 1994-10-27 | 1996-11-19 | Sharp Kabushiki Kaisha | Llithium secondary battery and process for preparing negative-electrode active material for use in the same |
| JP2006032070A (en) * | 2004-07-14 | 2006-02-02 | Kri Inc | Nonaqueous secondary battery |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3135613B2 (en) | 2001-02-19 |
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