JPH07312217A - Lithium secondary battery - Google Patents
Lithium secondary batteryInfo
- Publication number
- JPH07312217A JPH07312217A JP6151665A JP15166594A JPH07312217A JP H07312217 A JPH07312217 A JP H07312217A JP 6151665 A JP6151665 A JP 6151665A JP 15166594 A JP15166594 A JP 15166594A JP H07312217 A JPH07312217 A JP H07312217A
- Authority
- JP
- Japan
- Prior art keywords
- positive electrode
- lithium
- secondary battery
- lithium secondary
- 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、リチウム二次電池に関
する。より詳しくは、本発明は、特定の正極活物質を使
用することにより、優れた電池特性を安価に達成するリ
チウム二次電池に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lithium secondary battery. More specifically, the present invention relates to a lithium secondary battery that achieves excellent battery characteristics at low cost by using a specific positive electrode active material.
【０００２】[0002]
【従来の技術】近年のカメラ一体型ＶＴＲ、電話、ラッ
プトップコンピューター等の電子機器の小型軽量化、ポ
ータブル化に伴い、軽量で高容量の二次電池が求められ
るようになっており、その開発が進められている。その
中でも、リチウム二次電池は、従来から使用されている
ニッケル−カドミウム二次電池や鉛二次電池と比較して
軽量で、高エネルギー密度が得られ、高電圧を発生で
き、無公害の電池を実現できるため、活発に研究が進め
られている。この場合、研究の一つの柱は、リチウム二
次電池に適した正極活物質の開発にある。2. Description of the Related Art With the recent trend toward smaller and lighter electronic devices such as camera-integrated VTRs, telephones, laptop computers, etc., and portable devices, lightweight and high-capacity secondary batteries have been demanded and developed. Is being promoted. Among them, lithium secondary batteries are lighter in weight than conventional nickel-cadmium secondary batteries and lead secondary batteries, have high energy density, can generate high voltage, and are pollution-free batteries. Therefore, research is being actively pursued. In this case, one pillar of the research is to develop a positive electrode active material suitable for a lithium secondary battery.
【０００３】従来、正極活物質として、例えば、チタ
ン、モリブデン、ニオビウム、バナジウム、ジルコニウ
ム等のカルコゲナイド（硫化物、セレン化物、テルル化
物）や、モリブデン、タングステン、バナジウム等の金
属酸化物もしくは鉄等のハロゲン化物などが提案されて
いる。Conventionally, as positive electrode active materials, for example, chalcogenides (sulfides, selenides, tellurides) such as titanium, molybdenum, niobium, vanadium and zirconium, metal oxides such as molybdenum, tungsten and vanadium, or iron are used. Halides have been proposed.
【０００４】しかし、これらの正極活物質を使用したリ
チウム二次電池は、電池特性や経済性が実用上十分でな
いために実用化されているものは少ない。例えば、硫化
モリブデンを使用したものは、放電電位が低く、過充電
に弱い等の欠点を有している。また、バナジウム酸化物
を使用したものは放電電位は高いが放電容量が比較的小
さく、充放電サイクルに伴う容量低下も大きい。However, few lithium secondary batteries using these positive electrode active materials have been put into practical use because the battery characteristics and economical efficiency are not practically sufficient. For example, those using molybdenum sulfide have drawbacks such as low discharge potential and weakness against overcharge. In addition, the one using vanadium oxide has a high discharge potential, but the discharge capacity is relatively small, and the capacity decreases with charge / discharge cycles.
【０００５】これに対して、近年、放電電圧が高く、サ
イクル特性に優れた正極活物質としてリチウム含有酸化
コバルト（ＬｉｘＣｏＯ２：式中、ｘは電池の充放電状
態によって異なり、通常０．０５≦ｘ≦１．１０であ
る）が提案されており、これを用いたリチウム二次電池
が実用化されている。また、安価に得られる正極活物質
として、硫酸第二鉄（Ｆｅ２（ＳＯ４）３）が提案され
ている（ＥＣＳ Ｓｐｒｉｎｇ Ｍｅｅｔｉｎｇ，Ｈｏ
ｎｏｌｕｌｕ，Ｈａｗａｉｉ，Ｍａｙ １６−２１，１
９９３，Ｅｘｔｅｎｄｅｄ Ａｂｓｔｒａｃｔ，ｖｏ
ｌ．９３−１，Ｎｏ．８７，ｐ１３０）。On the other hand, in recent years, lithium-containing cobalt oxide (Li x CoO 2 : as a positive electrode active material having a high discharge voltage and excellent cycle characteristics): In the formula, x varies depending on the charging / discharging state of the battery. 05 ≦ x ≦ 1.10) has been proposed, and a lithium secondary battery using this has been put into practical use. Ferric sulfate (Fe 2 (SO 4 ) 3 ) has been proposed as a positive electrode active material that can be obtained at low cost (ECS Spring Meeting, Ho).
nolulu, Hawaii, May 16-21,1
993, Extended Abstract, vo
l. 93-1, No. 87, p130).
【０００６】[0006]
【発明が解決しようとする課題】しかしながら、リチウ
ム含有酸化コバルト（ＬｉｘＣｏＯ２）は、その原料と
なるコバルトが高価であり、さらに特定地域に偏在して
いるために経済的に安定供給を確保することが難しいと
いう問題を有している。また、硫酸第二鉄（Ｆｅ２（Ｓ
Ｏ４）３）は、（ＮＨ４）２Ｆｅ２（ＳＯ４）２・６Ｈ
２Ｏを焼成したり、硫酸第二鉄水和物（Ｆｅ２（Ｓ
Ｏ４）３・ｎＨ２Ｏ）を焼成したりすることにより得ら
れるが、前者の場合、焼成過程でＮＯｘやＳＯｘが発生
するため工業的には不利であるという問題があり、ま
た、後者の場合、結晶水が完全に除去できない等の問題
がある。However, since cobalt as a raw material of lithium-containing cobalt oxide (Li x CoO 2 ) is expensive and the lithium-containing cobalt oxide is unevenly distributed in a specific area, a stable supply is secured economically. It is difficult to do. Further, ferric sulfate (Fe 2 (S
O 4) 3) is, (NH 4) 2 Fe 2 (SO 4) 2 · 6H
2 O is fired or ferric sulfate hydrate (Fe 2 (S
O 4 ) 3 · nH 2 O) is obtained by firing, but in the former case, there is a problem that NO x and SO x are generated in the firing process, which is industrially disadvantageous. In the latter case, there is a problem that the water of crystallization cannot be completely removed.
【０００７】本発明は、このような従来技術の課題を解
決しようとするものであり電池特性及び経済性の両面に
優れたリチウム二次電池を提供することを目的とする。The present invention is intended to solve the problems of the prior art, and an object of the present invention is to provide a lithium secondary battery excellent in both battery characteristics and economy.
【０００８】[0008]
【課題を解決するための手段】本発明者らは、上記の目
的を達成するために種々の検討を重ねた結果、正極活物
質として、Ｆｅ２（ＳＯ４）ｘ（ＭｏＯ４）３−ｘを使
用することが有効であることを見出し、本発明を完成さ
せるに至った。As a result of various studies to achieve the above object, the present inventors have found that Fe 2 (SO 4 ) x (MoO 4 ) 3-x is used as a positive electrode active material. It has been found that the use of is effective, and the present invention has been completed.
【０００９】即ち、本発明は、リチウムをドープ、脱ド
ープできる材料、金属リチウム又はリチウム合金からな
る負極と、正極と、非水溶媒に電解質が溶解されている
非水電解液とを備えるリチウム二次電池において、正極
が組成式Ｆｅ２（ＳＯ４）ｘ（ＭｏＯ４）３−ｘで表さ
れる正極活物質を含むことを特徴とするリチウム二次電
池を提供する。That is, the present invention provides a lithium battery including a negative electrode made of a material capable of doping and dedoping lithium, metallic lithium or a lithium alloy, a positive electrode, and a non-aqueous electrolytic solution in which an electrolyte is dissolved in a non-aqueous solvent. Provided is a secondary battery, wherein the positive electrode contains a positive electrode active material represented by a composition formula Fe 2 (SO 4 ) x (MoO 4 ) 3-x .
【００１０】以下、本発明を詳細に説明する。The present invention will be described in detail below.
【００１１】本発明のリチウム二次電池においては、上
述のように、正極を構成する正極活物質として、Ｆｅ２
（ＳＯ４）ｘ（ＭｏＯ４）３−ｘを使用することを特徴
としている。このように、硫酸第二鉄とモリブデン酸鉄
との複塩を正極活物質として使用することにより、後述
するように、明確なカットオフ電位、安定な作動電位及
び安定なサイクル特性などの電池特性並びに低コストの
両面に優れたリチウム二次電池を提供することができ
る。In the lithium secondary battery of the present invention, as described above, Fe 2 is used as the positive electrode active material forming the positive electrode.
(SO 4 ) x (MoO 4 ) 3-x is used. Thus, by using the double salt of ferric sulfate and iron molybdate as the positive electrode active material, the battery characteristics such as a clear cut-off potential, a stable operating potential, and a stable cycle characteristic will be described later. In addition, it is possible to provide a lithium secondary battery that is excellent in both aspects of low cost.
【００１２】本発明で使用する正極活物質の組成式中の
ｘに関し、ｘが小さすぎるとＭｏの含有率が上がり製造
コスト的に不利となり、ｘが大きすぎると放電容量が大
きく低下する傾向がある。従って、ｘの範囲は、好まし
くは０＜ｘ≦１．８、より好ましくは０＜ｘ≦１．５と
する。Regarding x in the composition formula of the positive electrode active material used in the present invention, if x is too small, the Mo content increases, which is disadvantageous in manufacturing cost, and if x is too large, the discharge capacity tends to largely decrease. is there. Therefore, the range of x is preferably 0 <x ≦ 1.8, more preferably 0 <x ≦ 1.5.
【００１３】本発明で正極活物質として使用するＦｅ２
（ＳＯ４）ｘ（ＭｏＯ４）３−ｘは、公知の方法により
製造することができる。例えば、酸化第二鉄（Ｆｅ２Ｏ
３）と酸化モリブデン（ＭｏＯ３）と硫酸第二鉄水和物
（Ｆｅ２（ＳＯ４）３・ｎＨ２Ｏ）とを所定比で混合し
た後、酸素含有雰囲気下で焼成することにより好ましく
製造することができる。あるいは、硝酸第二鉄もしくは
塩化第二鉄の水溶液とパラモリブデン酸アンモニウムの
水溶液とを混合し、生成した沈殿物を濾取し、乾燥し、
酸素雰囲気下で焼成することによりＦｅ２（ＭｏＯ４）
３を調製し、これと硫酸第二鉄水和物（Ｆｅ２（Ｓ
Ｏ４）３・ｎＨ２Ｏ）とを所定比で混合し、酸素含有雰
囲気下で焼成することにより好ましく製造することがで
きる。これらの方法によれば、硫酸鉄系の材料を使用し
ているにもかかわらず、ＮＯｘやＳＯｘなどの発生がな
く、また、結晶水が仮に残存したとしてもその影響を排
除することができる。従って、Ｆｅ２（ＳＯ４）ｘ（Ｍ
ｏＯ４）３−ｘは、無公害で、簡便且つ低コストで得る
ことができる。Fe 2 used as the positive electrode active material in the present invention
(SO 4) x (MoO 4 ) 3-x can be prepared by known methods. For example, ferric oxide (Fe 2 O
3 ), molybdenum oxide (MoO 3 ) and ferric sulfate hydrate (Fe 2 (SO 4 ) 3 .nH 2 O) are mixed at a predetermined ratio, and then preferably baked in an oxygen-containing atmosphere. can do. Alternatively, an aqueous solution of ferric nitrate or ferric chloride and an aqueous solution of ammonium paramolybdate are mixed, the resulting precipitate is collected by filtration, dried,
Fe 2 (MoO 4 ) by firing in an oxygen atmosphere
3 was prepared and ferric sulfate hydrate (Fe 2 (S
O 4 ) 3 · nH 2 O) is mixed at a predetermined ratio, and the mixture is baked in an oxygen-containing atmosphere. According to these methods, although an iron sulfate-based material is used, NO x and SO x are not generated, and even if crystallization water remains, its influence can be eliminated. it can. Therefore, Fe 2 (SO 4 ) x (M
oO 4 ) 3-x is pollution-free and can be obtained easily and at low cost.
【００１４】なお、このようなＦｅ２（ＳＯ４）ｘ（Ｍ
ｏＯ４）３−ｘを使用して正極を構成するに際しては、
公知の導電剤や結着剤等を添加することができる。Note that such Fe 2 (SO 4 ) x (M
When forming a positive electrode using oO 4 ) 3-x ,
Known conductive agents, binders, etc. can be added.
【００１５】本発明において、負極は、リチウムをドー
プ、脱ドープできる材料、金属リチウム又はリチウム合
金を使用して構成する。このような負極を形成する材料
または負極活物質のうちリチウムをドープ、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
ポリマー等を使用することができる。また、リチウム合
金としては、例えば、リチウム−アルミニウム合金等を
使用することができる。中でも、負極としてに金属リチ
ウムを使用した場合には、３Ｖ付近に平坦な作動電圧が
得られ、従来の１．５Ｖ系電池と互換性よく使用するこ
とが可能となるので好ましい。また、炭素質材料を使用
する場合には、予め炭素質材料中にリチウムをドープし
ておくことが好ましい。。In the present invention, the negative electrode is composed of a material capable of doping or dedoping lithium, metallic lithium or a lithium alloy. Examples of the material forming the negative electrode or the material capable of being doped with lithium out of the negative electrode active material include pyrolytic carbons, cokes (pitch coke, needle coke, petroleum coke, etc.), graphites, glass Carbonaceous materials, organic polymer compound fired products (phenolic resin, furan resin, etc. fired at an appropriate temperature to carbonize), carbonaceous materials such as carbon fiber and activated carbon, or polymers such as polyacetylene and polypyrrole can do. Moreover, as the lithium alloy, for example, a lithium-aluminum alloy or the like can be used. Above all, when metallic lithium is used as the negative electrode, a flat operating voltage is obtained in the vicinity of 3 V, and it is possible to use it with good compatibility with a conventional 1.5 V battery, which is preferable. When using a carbonaceous material, it is preferable to dope lithium into the carbonaceous material in advance. .
【００１６】本発明において、非水電解液は従来の非水
系リチウム二次電池と同様のものを使用することができ
る。すなわち、非水電解液の非水溶媒としては、例えば
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−ブチロ
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を使用する
ことができる。特に、電圧に安定な点からプロピレンカ
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等の環状カーボネート類、
又は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を使用す
ることが好ましい。また、このような非水溶媒は、１種
または２種以上を組み合わせて使用することができる。In the present invention, the same non-aqueous electrolyte as the conventional non-aqueous lithium secondary battery can be used. That is, as the non-aqueous solvent of the non-aqueous electrolytic solution, for example, propylene carbonate, ethylene carbonate, butylene carbonate, vinylene carbonate, γ-butyrolactone, 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, cyclic carbonates such as propylene carbonate, ethylene carbonate, butylene carbonate, vinylene carbonate, etc. from the viewpoint of stable voltage,
Alternatively, it is preferable to use chain carbonates such as dimethyl carbonate, diethyl carbonate and dipropyl carbonate. Further, such non-aqueous solvent may be used alone or in combination of two or more kinds.
【００１７】また、非水溶媒に溶解させる電解質として
は、例えば、ＬｉＣｌＯ４、ＬｉＡｓＦ６、ＬｉＰ
Ｆ６、ＬｉＢＦ４、ＬｉＣＦ３ＳＯ３、ＬｉＮ（ＣＦ３
ＳＯ２）２等を使用でき、このうち特にＬｉＰＦ６やＬ
ｉＢＦ４を使用することが好ましい。The electrolyte to be dissolved in the non-aqueous solvent is, for example, LiClO 4 , LiAsF 6 or LiP.
F 6 , LiBF 4 , LiCF 3 SO 3 , LiN (CF 3
SO 2 ) 2 or the like can be used, among which LiPF 6 or L
It is preferred to use iBF 4 .
【００１８】本発明の電池は、電池形状については特に
限定されることはない。円筒型、角型、コイン型、ボタ
ン型等の種々の形状にすることができる。The shape of the battery of the present invention is not particularly limited. Various shapes such as a cylindrical shape, a square shape, a coin shape, and a button shape can be used.
【００１９】[0019]
【作用】本発明のリチウム二次電池は、正極活物質とし
て組成式Ｆｅ２（ＳＯ４）ｘ（ＭｏＯ４）３−ｘで表さ
れる化合物を使用するが、この正極活物質は工業的に容
易に得られ、また、主たる構成元素が鉄であるため安価
に得られるので、優れた経済性を有する。The lithium secondary battery of the present invention uses a compound represented by the composition formula Fe 2 (SO 4 ) x (MoO 4 ) 3-x as the positive electrode active material. It is easily obtained, and since the main constituent element is iron, it can be obtained at a low cost, so that it has excellent economic efficiency.
【００２０】さらに、この正極活物質を使用したリチウ
ム二次電池は、活物質内でのリチウムイオンの拡散速度
が速いため、電池特性も向上したものとなる。特に、充
電に際して定電流充電すると、まず電圧が３Ｖ付近で一
定となり、その後急速に電圧が上昇するが、この時点で
ほぼ１００％の充電が完了している。したがって、１０
０％の充電をするために定電流充電をするだけで足り、
従来のように定電流充電後さらに定電圧充電をすること
が不要となる。よって、簡略化した充電器を使用し、急
速充電をすることが可能となる。Further, the lithium secondary battery using this positive electrode active material has improved battery characteristics because the diffusion rate of lithium ions in the active material is high. In particular, when constant-current charging is performed during charging, the voltage first becomes constant at around 3 V, and then the voltage rises rapidly, but at this time, almost 100% charging is completed. Therefore, 10
Only constant current charging is required to charge 0%,
It becomes unnecessary to carry out constant voltage charging after constant current charging as in the conventional case. Therefore, it becomes possible to perform quick charging by using a simplified charger.
【００２１】また、本発明のリチウム二次電池において
負極に金属リチウムを使用すると、３Ｖ付近に平坦な作
動電圧が得られるので、従来の１．５Ｖ系電池と互換性
よく使用することが可能となる。Further, in the lithium secondary battery of the present invention, when metallic lithium is used for the negative electrode, a flat operating voltage can be obtained in the vicinity of 3V, so that it can be used with good compatibility with the conventional 1.5V type battery. Become.
【００２２】[0022]
【実施例】以下、本発明を実施例により具体的に説明す
る。EXAMPLES The present invention will be specifically described below with reference to examples.
【００２３】実施例１〜５ (i) 正極活物質の合成 酸化鉄(III) と酸化モリブデンと硫酸第二鉄水和物（Ｆ
ｅ２（ＳＯ４）３・ｎＨ２Ｏ）とを、Ｆｅ：Ｓ：Ｍｏ＝
２：０．３：２．７となるように混合し、酸素雰囲気中
７００℃で７時間加熱処理して正極活物質を調製した。
この正極活物質をサンプル１とした。同様に、酸化鉄(I
II) と酸化モリブデンと硫酸第二鉄水和物とを、表１に
示すＦｅ：Ｓ：Ｍｏの比となるようにする以外は同様に
して正極活物質サンプル２〜５を調製した。Examples 1 to 5 (i) Synthesis of Positive Electrode Active Material Iron (III) oxide, molybdenum oxide, and ferric sulfate hydrate (F
e 2 (SO 4 ) 3 · nH 2 O) and Fe: S: Mo =
The mixture was mixed so as to be 2: 0.3: 2.7 and heat-treated in an oxygen atmosphere at 700 ° C. for 7 hours to prepare a positive electrode active material.
This positive electrode active material was used as Sample 1. Similarly, iron oxide (I
Positive electrode active material samples 2 to 5 were prepared in the same manner except that II), molybdenum oxide, and ferric sulfate hydrate were adjusted to have the ratio of Fe: S: Mo shown in Table 1.
【００２４】[0024]
【表１】 (ii)正極の作製 上記正極活物質サンプル１〜５のそれぞれを８０重量
％、導電剤としてカーボンブラックを１５重量％、結着
剤としてフッ素樹脂粉末５重量％を加え、乳鉢で十分混
合し、その混合物を直径１６ｍｍのＳＵＳ網上にディス
ク状に加圧成形し、正極活物質サンプル１〜５に対応し
た正極板１〜５を得た。 (iii) リチウム二次電池の作製 図１のコイン型電池（外径２０．０ｍｍ、厚さ２．５ｍ
ｍ）を作製した。この電池は、負極１と、上述の正極板
１〜５からなる正極２とをセパレータ３を介してそれぞ
れ負極電池缶４及び正極電池缶５に収納し、封口ガスケ
ット６をかしめることにより作製したものである。な
お、正極板１を使用したものを実施例１の電池、正極板
２を使用したものを実施例２の電池、正極板３を使用し
たものを実施例３の電池、正極板４を使用したものを実
施例４の電池、正極板５を使用したものを実施例５の電
池とした。[Table 1] (ii) Preparation of Positive Electrode 80% by weight of each of the above-mentioned positive electrode active material samples 1 to 5, 15% by weight of carbon black as a conductive agent, and 5% by weight of fluororesin powder as a binder were added and sufficiently mixed in a mortar, The mixture was pressure-molded on a SUS net having a diameter of 16 mm in a disk shape to obtain positive electrode plates 1 to 5 corresponding to positive electrode active material samples 1 to 5. (iii) Preparation of lithium secondary battery Coin-type battery of FIG. 1 (outer diameter 20.0 mm, thickness 2.5 m
m) was prepared. This battery was manufactured by accommodating the negative electrode 1 and the positive electrode 2 composed of the positive electrode plates 1 to 5 in the negative electrode battery can 4 and the positive electrode battery can 5 via the separator 3 and caulking the sealing gasket 6. It is a thing. The positive electrode plate 1 was used for the battery of Example 1, the positive electrode plate 2 was used for the battery of Example 2, the positive electrode plate 3 was used for the battery of Example 3, and the positive electrode plate 4 was used. The battery was used as the battery of Example 4 and the battery using the positive electrode plate 5 was used as the battery of Example 5.
【００２５】ここで、負極１としては、リチウム圧延板
を打ち抜いたものを使用した。また、セパレータ３とし
ては、ポリプロピレン不織布を用意し、一方、電解液と
して、プロピレンカーボネート（ＰＣ）とジメチルカー
ボネート（ＤＭＣ）との混合溶媒（ＰＣ：ＤＭＣ＝１：
１（体積比））に六フッ素リン酸リチウム（ＬｉＰ
Ｆ６）を１ｍｏｌ／ｌの割合で溶解させたものを調製
し、これをポリプロピレン不織布からなるセパレータ３
に含浸させて使用した。Here, as the negative electrode 1, a punched lithium rolled plate was used. A polypropylene nonwoven fabric is prepared as the separator 3, while a mixed solvent of propylene carbonate (PC) and dimethyl carbonate (DMC) (PC: DMC = 1: 1) is used as an electrolytic solution.
1 (volume ratio) to lithium hexafluorophosphate (LiP
F 6 ) was dissolved at a ratio of 1 mol / l to prepare a separator 3 which was made of polypropylene nonwoven fabric.
It was used by being impregnated with.
【００２６】（電池特性試験）得られた電池の放電特性
を、定電流（０．５ｍＡ／ｃｍ２）で充放電させるとい
う充放電サイクルを繰り返すことにより測定した。ま
ず、これらの実施例の電池の中で中間的な組成の正極活
物質を使用した実施例３の電池の５サイクル目と２０サ
イクル目の放電特性を図２に示す。この図から、実施例
３の電池は３Ｖ付近に平坦な作動電圧を有しており、安
定した放電特性を有することがわかる。また、５サイク
ル目と２０サイクル目の放電特性を比較すると、充放電
サイクルの繰り返しによる劣化も小さいことがわかる。(Battery Characteristic Test) The discharge characteristic of the obtained battery was measured by repeating a charge / discharge cycle of charging and discharging at a constant current (0.5 mA / cm 2 ). First, FIG. 2 shows the discharge characteristics at the 5th cycle and the 20th cycle of the battery of Example 3 using a positive electrode active material having an intermediate composition among the batteries of these Examples. From this figure, it is understood that the battery of Example 3 has a flat operating voltage near 3 V and has stable discharge characteristics. Further, comparing the discharge characteristics at the 5th cycle and the 20th cycle, it can be seen that the deterioration due to repeated charge / discharge cycles is small.
【００２７】次に、実施例１〜５までの電池の１０サイ
クル目の放電容量を比較した。その結果を図３に示す。
この図から、組成式Ｆｅ２（ＳＯ４）ｘ（ＭｏＯ４）
３−ｘにおけるｘの値が実用的には１．８以下、好まし
くは１．５以下であることがわかる。Next, the discharge capacities at the 10th cycle of the batteries of Examples 1 to 5 were compared. The result is shown in FIG.
From this figure, the composition formula Fe 2 (SO 4 ) x (MoO 4 )
It can be seen that the value of x in 3-x is practically 1.8 or less, preferably 1.5 or less.
【００２８】実施例６〜１０ (i) 正極活物質の合成及び正極板の作製 硝酸鉄(III) 水溶液とパラモリブデン酸アンモニウム水
溶液とを、Ｆｅ：Ｍｏ＝２：３となるように混合し、黄
色の折出物を得た。この折出物を分別し、純水で洗浄
し、大気中６０℃で乾燥させ、さらに酸素雰囲気中７０
０℃で６時間加熱処理してＦｅ２（ＭｏＯ４）３を得
た。これと硫酸第二鉄水和物（Ｆｅ２（ＳＯ４）３・ｎ
Ｈ２Ｏ）とをＳ：Ｍｏ＝０．３：２．７となるように混
合し、酸素雰囲気中７００℃で７時間加熱処理して正極
活物質を調製した。この正極活物質をサンプル６とし
た。同様に、Ｆｅ２（ＭｏＯ４）３と硫酸第二鉄水和物
とを、表２に示すＳ：Ｍｏの比となるようにする以外は
同様にして正極活物質サンプル７〜１０を調製した。そ
して、正極活物質として、正極活物質サンプル１に代え
て上記正極活物質サンプル６〜１０を使用する以外は実
施例１と同様にして正極板６〜１０を作製した。Examples 6 to 10 (i) Synthesis of positive electrode active material and production of positive electrode plate An iron (III) nitrate aqueous solution and an ammonium paramolybdate aqueous solution were mixed so that Fe: Mo = 2: 3, A yellow extrudate was obtained. The exudates are separated, washed with pure water, dried in the atmosphere at 60 ° C., and further dried in an oxygen atmosphere at 70 ° C.
0 6 hours of heat treatment to at ℃ obtain a Fe 2 (MoO 4) 3. This and ferric sulfate hydrate (Fe 2 (SO 4 ) 3 · n
H 2 O) was mixed so that S: Mo = 0.3: 2.7 and heat-treated at 700 ° C. for 7 hours in an oxygen atmosphere to prepare a positive electrode active material. This positive electrode active material was used as sample 6. Similarly, positive electrode active material samples 7 to 10 were prepared in the same manner except that Fe 2 (MoO 4 ) 3 and ferric sulfate hydrate had the S: Mo ratio shown in Table 2. . Then, positive electrode plates 6 to 10 were produced in the same manner as in Example 1 except that the above positive electrode active material samples 6 to 10 were used as the positive electrode active material in place of the positive electrode active material sample 1.
【００２９】[0029]
【表２】 (ii)リチウム二次電池の作製 上記(i) で得た正極板６〜１０を使用し、実施例１と同
様にして実施例６〜１０のリチウム二次電池を作製し
た。[Table 2] (ii) Production of Lithium Secondary Battery Using the positive electrode plates 6 to 10 obtained in (i) above, lithium secondary batteries of Examples 6 to 10 were produced in the same manner as in Example 1.
【００３０】（電池特性試験）得られた電池の放電特性
を実施例１〜５と同様にして測定した結果、実施例１〜
５と同様の結果が得られた。(Battery characteristics test) The discharge characteristics of the obtained batteries were measured in the same manner as in Examples 1 to 5, and
Results similar to 5 were obtained.
【００３１】実施例１１〜１５ (i) 正極活物質の合成及び正極板の作製 実施例１〜５の正極活物質サンプル１〜５と同様の正極
活物質サンプル１１〜１５を調製し、更に実施例１に従
って正極板１１〜１５を作製した。 (ii)リチウム二次電池の作製 電解液として実施例１と同様のものを調製した。Examples 11 to 15 (i) Synthesis of Positive Electrode Active Material and Production of Positive Electrode Plate Positive electrode active material samples 11 to 15 similar to the positive electrode active material samples 1 to 5 of Examples 1 to 5 were prepared and further carried out. Positive electrode plates 11 to 15 were manufactured according to Example 1. (ii) Preparation of Lithium Secondary Battery The same electrolytic solution as in Example 1 was prepared.
【００３２】また、負極を作製するに際しては、まず、
カーボン（フルフリルアルコールを焼成して得られた難
黒鉛化カーボン）とフッ素樹脂粉末とを重量比で９：１
に混合し、これを正極の作製の場合と同様に、直径１６
ｍｍのＳＵＳ網上にディスク状に加圧成形し、負極板と
した。そして、これをリチウム二次電池に組む前に、予
め、電解液中でリチウム金属電極と対向させて通電し、
負極板の中にリチウムイオンを挿入した。こうして負極
板を上述の正極板と組み合わせてリチウム二次電池を構
成した場合に、この負極板でリチウムイオンのドープ、
脱ドープが起こるようにした。In producing the negative electrode, first,
Carbon (non-graphitizable carbon obtained by firing furfuryl alcohol) and fluororesin powder in a weight ratio of 9: 1
And mixed with the same as in the case of producing the positive electrode,
It was pressure-molded into a disk shape on a SUS mesh of mm to obtain a negative electrode plate. Then, before assembling this into a lithium secondary battery, it is energized by facing the lithium metal electrode in the electrolytic solution in advance,
Lithium ions were inserted into the negative electrode plate. In this way, when a lithium secondary battery is constructed by combining the negative electrode plate with the above positive electrode plate, the negative electrode plate is doped with lithium ions,
Allowed dedoping.
【００３３】その後、この負極板と上述の正極板１１〜
１５と電解液とを使用して実施例１と同様に，外径２
０．０ｍｍ、厚さ２．５ｍｍの実施例１１〜１５のコイ
ン型電池を作製した。Thereafter, the negative electrode plate and the positive electrode plates 11 to 11 described above are used.
15 and the electrolytic solution, the outer diameter 2
The coin type batteries of Examples 11 to 15 having a thickness of 0.0 mm and a thickness of 2.5 mm were produced.
【００３４】（電池特性試験）得られた電池の放電特性
を、実施例１〜５と同様に測定した。その結果、実施例
１〜５と同様のサイクル特性を示すことがわかった。た
だし、図４に示すように、これらの実施例１１〜１５の
電池の中で中間的な組成の正極活物質を使用した実施例
１３の電池の５サイクル目と２０サイクル目の放電特性
は、実施例３の電池の放電特性（図２）に比べ、作動電
圧が時間の経過に従って徐々に低下していた。これは、
負極として比較的結晶化度の低い炭素質材料を使用した
ためと考えられる。グラファイトなどの結晶性の高い炭
素質材料を負極として使用することにより、安定な放電
特性を示すことが期待できる。(Battery Characteristic Test) The discharge characteristics of the obtained battery were measured in the same manner as in Examples 1-5. As a result, it was found that the same cycle characteristics as those of Examples 1 to 5 were exhibited. However, as shown in FIG. 4, the discharge characteristics at the 5th cycle and the 20th cycle of the battery of Example 13 using the positive electrode active material having an intermediate composition among the batteries of Examples 11 to 15 were as follows. Compared to the discharge characteristics (FIG. 2) of the battery of Example 3, the operating voltage gradually decreased with the passage of time. this is,
This is probably because a carbonaceous material having a relatively low crystallinity was used as the negative electrode. By using a highly crystalline carbonaceous material such as graphite as the negative electrode, stable discharge characteristics can be expected.
【００３５】実施例１６〜２０ (i) 正極活物質の合成及び正極板の作製 実施例６〜１０の正極活物質サンプル６〜１０と同様の
正極活物質サンプル１１６〜２０を調製し、更に実施例
１に従って正極板１６〜２０を作製した。 (ii)リチウム二次電池の作製 正極板１６〜２０を使用する以外は実施例１１〜１５と
同様にして実施例１６〜２０のリチウム二次電池を作製
した。Examples 16 to 20 (i) Synthesis of Positive Electrode Active Material and Production of Positive Electrode Plate Positive electrode active material samples 116 to 20 similar to the positive electrode active material samples 6 to 10 of Examples 6 to 10 were prepared and further carried out. Positive electrode plates 16 to 20 were manufactured according to Example 1. (ii) Production of Lithium Secondary Battery Lithium secondary batteries of Examples 16 to 20 were produced in the same manner as in Examples 11 to 15 except that the positive electrode plates 16 to 20 were used.
【００３６】（電池特性試験）得られた電池の放電特性
を実施例１〜５と同様にして測定した結果、実施例１１
〜１５と同様の結果が得られた。(Battery Characteristic Test) The discharge characteristics of the obtained battery were measured in the same manner as in Examples 1 to 5, and the result was Example 11.
Results similar to ~ 15 were obtained.
【００３７】[0037]
【発明の効果】本発明によれば、電池特性及び経済性の
両面に優れたリチウム二次電池を得ることが可能とな
る。According to the present invention, it is possible to obtain a lithium secondary battery excellent in both battery characteristics and economy.
【図１】実施例で作製したリチウム二次電池の断面図で
ある。FIG. 1 is a cross-sectional view of a lithium secondary battery manufactured in an example.
【図２】実施例３のリチウム二次電池の放電特性図であ
る。FIG. 2 is a discharge characteristic diagram of the lithium secondary battery of Example 3.
【図３】実施例１〜５のリチウム二次電池の放電容量特
性図である。FIG. 3 is a discharge capacity characteristic diagram of the lithium secondary batteries of Examples 1 to 5.
【図４】実施例１３のリチウム二次電池の放電特性図で
ある。FIG. 4 is a discharge characteristic diagram of the lithium secondary battery of Example 13.
１ 負極 ２ 正極 ３ セパレータ ４ 負極缶 ５ 正極缶 ６ 封口ガスケット 1 Negative electrode 2 Positive electrode 3 Separator 4 Negative electrode can 5 Positive electrode can 6 Sealing gasket
Claims (4)
料、金属リチウム又はリチウム合金からなる負極と、正
極と、非水溶媒に電解質が溶解されている非水電解液と
を備えるリチウム二次電池において、正極が組成式 【化１】Ｆｅ２（ＳＯ４）ｘ（ＭｏＯ４）３−ｘ で表される正極活物質を含むことを特徴とするリチウム
二次電池。1. A lithium secondary battery comprising a negative electrode made of a material capable of doping and dedoping lithium, metallic lithium or a lithium alloy, a positive electrode, and a non-aqueous electrolytic solution in which an electrolyte is dissolved in a non-aqueous solvent, A lithium secondary battery, wherein the positive electrode contains a positive electrode active material represented by the composition formula: Fe 2 (SO 4 ) x (MoO 4 ) 3-x .
請求項１記載のリチウム二次電池。2. The lithium secondary battery according to claim 1, wherein x in the composition formula is 0 <x ≦ 1.8.
載のリチウム二次電池。3. The lithium secondary battery according to claim 1, wherein the negative electrode is made of metallic lithium.
る炭素質材料からなる請求項１記載のリチウム二次電
池。4. The lithium secondary battery according to claim 1, wherein the negative electrode is made of a carbonaceous material capable of being doped and dedoped with lithium.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15166594A JP3395370B2 (en) | 1994-03-22 | 1994-06-08 | Lithium secondary battery |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6-76607 | 1994-03-22 | ||
| JP7660794 | 1994-03-22 | ||
| JP15166594A JP3395370B2 (en) | 1994-03-22 | 1994-06-08 | Lithium secondary battery |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH07312217A true JPH07312217A (en) | 1995-11-28 |
| JP3395370B2 JP3395370B2 (en) | 2003-04-14 |
Family
ID=26417745
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP15166594A Expired - Fee Related JP3395370B2 (en) | 1994-03-22 | 1994-06-08 | Lithium secondary battery |
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| Country | Link |
|---|---|
| JP (1) | JP3395370B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5695893A (en) * | 1995-05-18 | 1997-12-09 | Nippon Telegraph And Telephone Corporation | Material for use in the positive electrodes of lithium batteries, its manufacture, and lithium batteries incorporating this material |
-
1994
- 1994-06-08 JP JP15166594A patent/JP3395370B2/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5695893A (en) * | 1995-05-18 | 1997-12-09 | Nippon Telegraph And Telephone Corporation | Material for use in the positive electrodes of lithium batteries, its manufacture, and lithium batteries incorporating this material |
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| Publication number | Publication date |
|---|---|
| JP3395370B2 (en) | 2003-04-14 |
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