JPH0477426B2 - - Google Patents
Info
- Publication number
- JPH0477426B2 JPH0477426B2 JP57096920A JP9692082A JPH0477426B2 JP H0477426 B2 JPH0477426 B2 JP H0477426B2 JP 57096920 A JP57096920 A JP 57096920A JP 9692082 A JP9692082 A JP 9692082A JP H0477426 B2 JPH0477426 B2 JP H0477426B2
- Authority
- JP
- Japan
- Prior art keywords
- charge
- lithium
- electrolyte
- present
- methyltetrahydrofuran
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Secondary Cells (AREA)
Description
【発明の詳細な説明】
本発明は、リチウム二次電池に用いる電解液に
関するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrolytic solution used in a lithium secondary battery.
リチウム負極活物質として用いる電池は、小
型・高エネルギ密度を有する電池として研究され
ているが、その二次化が大きな問題点となつてい
る。 Batteries used as lithium negative electrode active materials are being studied as small-sized batteries with high energy density, but secondaryization has become a major problem.
二次化が可能な正極活物質として、V2O3、
V6O13等の金属酸化物、TiS2、VS2等の層状化合
物が、Liとの間でトボケミカルな反応をする化合
物として知られており、現在までチタン、ジルコ
ニウム、ハフニウム、ニオビウム、タンタル、バ
ジウムの硫化物、セレン化物、テルル化物を用い
た電池（米国特許第4089052号明細書参照）等が
開示されている。 As a positive electrode active material that can be secondaryized, V 2 O 3 ,
Metal oxides such as V 6 O 13 and layered compounds such as TiS 2 and VS 2 are known as compounds that undergo tobochemical reactions with Li. Batteries (see US Pat. No. 4,089,052) using sulfide, selenide, and telluride of basium have been disclosed.
しかしながら、このような二次電池用正極活物
質の研究に比して、Li極の充放電特性に関する研
究は充分とはいえず、Li二次電池実現のために
は、充放電効率及びサイクル寿命等の充放電特性
の良好な電解液の探査が重大な問題となつてい
る。Li極の充放電効率を向上させる試みとしては
LiClO4／プロピレンカーボネイトにニトロメタ
ン、SO2等の添加剤を加える試み〔Electro‐
chimica.Acta.vol.22、第75頁〜83頁（1977）〕等
が行なわれているが必ずしも充分とはいえず、さ
らに特性の優れたリチウム二次電池用電解液が求
められている。 However, compared to such research on positive electrode active materials for secondary batteries, research on the charging and discharging characteristics of Li electrodes is not sufficient, and in order to realize Li secondary batteries, charging and discharging efficiency and cycle life are The search for electrolytes with good charge-discharge characteristics has become a serious issue. As an attempt to improve the charging and discharging efficiency of Li electrodes,
Attempt to add additives such as nitromethane and SO 2 to LiClO 4 /propylene carbonate [Electro-
chimica.Acta.vol. 22, pp. 75-83 (1977)], but they are not necessarily sufficient, and there is a need for an electrolytic solution for lithium secondary batteries with even better characteristics.
本発明は、このような現状に鑑みてなされたも
のであり、その目的はLi極の充放電特性の優れた
リチウム二次電池用非水電解液を提供することに
ある。 The present invention has been made in view of the current situation, and its purpose is to provide a non-aqueous electrolyte for lithium secondary batteries that has excellent charging and discharging characteristics of Li electrodes.
したがつて、本発明によるリチウム二次電池用
非水電解液はリチウム塩を有機溶媒に溶解させた
非水電解液において、前記非水電解液の有機溶媒
として、プロピレンカーボネートと２−メチルテ
トラハイドロフランとを体積比で２：８〜７：３
混合したものを使用した事を特徴とするものであ
る。 Therefore, the nonaqueous electrolyte for lithium secondary batteries according to the present invention is a nonaqueous electrolyte in which a lithium salt is dissolved in an organic solvent, and propylene carbonate and 2-methyltetrahydro are used as the organic solvent of the nonaqueous electrolyte. Volume ratio of furan to 2:8 to 7:3
It is characterized by the use of a mixture.
本発明によれば、有機溶媒としてプロピレンカ
ーボネイトと２−メチルテトラハイドロフランと
の混合溶媒を用いることにより、Li極の充放電特
性の優秀なリチウム二次電池用非水電解液を提供
することができる。 According to the present invention, by using a mixed solvent of propylene carbonate and 2-methyltetrahydrofuran as an organic solvent, it is possible to provide a nonaqueous electrolyte for lithium secondary batteries with excellent charge and discharge characteristics of Li electrodes. can.
本発明を更に詳しく説明する。 The present invention will be explained in more detail.
リチウム二次電池は、リチウムを負極活物質と
し、Li+イオンに対し、電気化学的に活性で、か
つLi+イオンと可逆的な電気化学反応を行なう物
質を正極活物質とし、リチウム塩を有機溶媒に溶
解させた非水電解液を用いたものであるが、この
リチウム二次電池用の有機溶媒として、本発明に
おいては、２−メチルテトラハイドロフランとプ
ロピレンカーボネイトの混合溶媒を用いる。 Lithium secondary batteries use lithium as a negative electrode active material, a positive electrode active material that is electrochemically active toward Li + ions and that undergoes a reversible electrochemical reaction with Li + ions, and a lithium salt as an organic material. Although a non-aqueous electrolyte dissolved in a solvent is used, in the present invention, a mixed solvent of 2-methyltetrahydrofuran and propylene carbonate is used as the organic solvent for this lithium secondary battery.
Li極の充放電効率を向上させるためには、溶媒
系中のLi塩が解離し易く、かつLi+イオンの移動
性が大きい事が必要であと考えられるが、そのた
めには、プロピレンカーボネイトの様な誘電率が
高く、Li塩を解離させ易い溶媒と、２−メチルテ
イラハイドロフランの様な粘度が低く、Li+イオ
ンの移動性を増大させる溶媒を最適な比率で混合
する事が効果的である。 In order to improve the charging and discharging efficiency of Li electrodes, it is thought that the Li salt in the solvent system must be easily dissociated and the mobility of Li + ions must be high. It is effective to mix a solvent with a high dielectric constant that easily dissociates Li salt with a solvent such as 2-methylteirahydrofuran that has low viscosity and increases the mobility of Li + ions in an optimal ratio. be.
本発明によるリチウム電池用非水電解液によれ
ば、非水電解液の有機溶媒としてプロピレンカー
ボネイト及び２−メチルテトラハイドロフランの
混合物を用いるので、形成されるリチウム電池の
充放電効率は著しく同上する。 According to the non-aqueous electrolyte for lithium batteries according to the present invention, since a mixture of propylene carbonate and 2-methyltetrahydrofuran is used as the organic solvent of the non-aqueous electrolyte, the charge/discharge efficiency of the formed lithium battery is significantly improved. .
本発明による電解液の有機溶媒は前述のよう
に、プロピレンカーボネイト及び２−メチルテト
ラハイドロフランであるが、これに溶解される溶
質は従来この種の電池に用いられる溶質を自由に
用いることができる。たとえば、LiClO4、
LiBF4、LiAsF6、LiPF6、LiAlCl4等の無機塩及
びCF3SO3Li、CF3COOLi等の有機塩を用いるこ
とができる。 As mentioned above, the organic solvent of the electrolyte according to the present invention is propylene carbonate and 2-methyltetrahydrofuran, but the solute dissolved therein can be any solute conventionally used in this type of battery. . For example, LiClO4 ,
Inorganic salts such as LiBF 4 , LiAsF 6 , LiPF 6 and LiAlCl 4 and organic salts such as CF 3 SO 3 Li and CF 3 COOLi can be used.
これらの溶質は前記有機溶媒に、それぞれ好ま
しくは0.5〜2.5N溶解される。プロピレンカーボ
ネイトに溶解する溶質が0.5N未満であると、充
放電特性が著しく低下し、2.5Nを超えると、溶
質は溶解しないからである。また２−メチルテト
ラハイドロフランに溶解する溶質の濃度が0.5N
未満であると、充放電特性が悪化し、2.5Nを超
えると粘度が上昇し、やはり充放電特性が低下す
る。最も好ましくは、それぞれ2N前後である。 These solutes are each preferably dissolved in 0.5 to 2.5N in the organic solvent. This is because if the amount of solute dissolved in propylene carbonate is less than 0.5N, the charge/discharge characteristics will be significantly reduced, and if it exceeds 2.5N, the solute will not dissolve. Also, the concentration of solute dissolved in 2-methyltetrahydrofuran is 0.5N.
If it is less than 2.5N, the charge and discharge characteristics will deteriorate, and if it exceeds 2.5N, the viscosity will increase and the charge and discharge characteristics will also deteriorate. Most preferably, each is around 2N.
プロピレンカーボネイト及び２−メチルテトラ
ハイドロフランの混合比は、前記溶質を0.5〜
2.5N溶解したプロピレンカーボネイト及び前記
溶質を0.5〜2.5N溶解した２−メチルテトラハイ
ドロフランの体積比で２：８〜７：３、最も好ま
しくは５：５前後である。前記溶質を溶解したプ
ロピレンカーボナイトの混合比が２：８より少な
いと、両者を混合した意味が薄くなり、２−メチ
ルテトラハイドロフラン単独系の充放電特性に近
づくことになり、また７：３より多いと、反対に
プロピレンカーボナイト単独系の充放電特性に近
づき、いずれにしても充放電特性が悪化するから
である。 The mixing ratio of propylene carbonate and 2-methyltetrahydrofuran is 0.5 to
The volume ratio of propylene carbonate dissolved in 2.5N and 2-methyltetrahydrofuran dissolved in 0.5 to 2.5N of the solute is 2:8 to 7:3, most preferably around 5:5. If the mixing ratio of propylene carbonite in which the solute is dissolved is less than 2:8, the meaning of mixing the two becomes weak, and the charge/discharge characteristics approach that of 2-methyltetrahydrofuran alone; If the amount is too large, the charge and discharge characteristics will approach those of propylene carbonite alone, and the charge and discharge characteristics will deteriorate in any case.
以下、本発明の実施例を説明する。 Examples of the present invention will be described below.
実施例 １
Pt極を作用極、対極にLiを参照電極としてLi
を用いた電池を組み、Pt極上にLiを析出させる
ことにより、Li極の充放電特性を測定した。電解
液にはINLiClO4を２−メチルテトラハイドロフ
ラン（以下、２−MeTHFと略記する）とプロピ
レンカーボネイト（以下、PCと略記する）にそ
れぞれ溶解したものを１：１体積比にさせたもの
を用いた。この電解液の導電率は7.9×10-3Ω-1cm
-1であり、INLiClO4／PC単独系の導電率である
６×10-3Ω-1cm-1より高かつた。Example 1 Pt electrode is used as a working electrode, Li is used as a counter electrode and Li is used as a reference electrode.
We assembled a battery using Pt and deposited Li on the Pt electrode to measure the charge/discharge characteristics of the Li electrode. The electrolyte was prepared by dissolving INLiClO 4 in 2-methyltetrahydrofuran (hereinafter abbreviated as 2-MeTHF) and propylene carbonate (hereinafter abbreviated as PC) at a volume ratio of 1:1. Using. The conductivity of this electrolyte is 7.9×10 -3 Ω -1 cm
-1 , which was higher than the conductivity of INLiClO 4 /PC alone, which was 6×10 -3 Ω -1 cm -1 .
測定は、まず5mA／cm2の定電流で１分間、Pt
極上にLiを析出させ充電した後、5mA／cm2の定
電流でPt極上に析出したLiをLi+イオンとして放
電するサイクル試験を行なつた。充放電効率は、
Pt極の電位変化より求め、Pt極上に析出したLi
をLi+イオンとして放電させるのに要した電気量
とPt極上にLiを析出させるために要した電気量
との比から算出した。 First, the measurement was performed using a constant current of 5 mA/cm 2 for 1 minute.
After depositing Li on the Pt electrode and charging it, a cycle test was performed in which the Li deposited on the Pt electrode was discharged as Li + ions at a constant current of 5 mA/cm 2 . The charge/discharge efficiency is
Li deposited on the Pt electrode, determined from the potential change of the Pt electrode.
It was calculated from the ratio of the amount of electricity required to discharge Li + ions to the amount of electricity required to deposit Li on the Pt electrode.
第１図は、充放電効率とサイクル数の関係を示
す図であり、図中のａは上記電解液を用いた場合
であり、ｂ及びｃは、それぞれ、1NLiClO4／プ
ロピレンカーボネイト及び2NLiClO4／２−メチ
ルテトラハイドロフラン単独系の電解液を用いた
場合の充放電特性を参考例として示した。第１図
から判るように、単独系（ｂ、ｃ）に比べて、混
合系ａは明らかに充放電特性は向上している。 FIG. 1 is a diagram showing the relationship between charge/discharge efficiency and cycle number. In the figure, a is the case when the above electrolyte is used, and b and c are 1NLiClO 4 /propylene carbonate and 2NLiClO 4 / The charging and discharging characteristics when using an electrolytic solution based solely on 2-methyltetrahydrofuran are shown as a reference example. As can be seen from FIG. 1, the charge/discharge characteristics of the mixed system a are clearly improved compared to the single systems (b, c).
実施例 ２
電解液として本発明の1N LiAsF6をPCと
2MeTEFの混合溶媒（体積混合比、１：１）に
溶解させたものを用いて実施例１と同様にしてリ
チウムの充放電特性を測定した。また、参考例と
して、電解液として1N LiAsF6をPCとテトラヒ
ドロフラン（THF）の混合溶媒（体積混合比、
１：１）に溶解したものを用いて実施例１の同様
にしてリチウムの充放電特性を測定した。本発明
の室温における上記電解液の導電率は9.8×
10-3S／cmであり、参考例の電解液の導電率は
15.2×10-3S／cmと本発明より高い値を示した。Example 2 Using 1N LiAsF 6 of the present invention as an electrolyte with PC
The charge-discharge characteristics of lithium were measured in the same manner as in Example 1 using 2MeTEF dissolved in a mixed solvent (volume mixing ratio, 1:1). In addition, as a reference example, 1N LiAsF 6 was used as an electrolyte in a mixed solvent of PC and tetrahydrofuran (THF) (volume mixing ratio,
The charge/discharge characteristics of lithium were measured in the same manner as in Example 1 using a solution of 1:1). The conductivity of the electrolyte at room temperature of the present invention is 9.8×
10 -3 S/cm, and the conductivity of the electrolyte in the reference example is
It showed a value of 15.2×10 -3 S/cm, which is higher than that of the present invention.
第２図に、充放電効率測定の結果を示す。第２
図は、リチウムの充放電効率とサイクル数の関係
を示す図であり、図中のａは上記の本発明の電解
液を用いた場合であり、図中のｂは上記の参考例
の電解液を用いた場合である。第２図からわかる
ように、参考例(b)では、二次電池としての特性は
不十分であるのに対し、本発明の電解液は飛躍的
に充放電サイクル特性が向上していることがわか
る。 Figure 2 shows the results of charging and discharging efficiency measurements. Second
The figure shows the relationship between the charge/discharge efficiency of lithium and the number of cycles; a in the figure is the case when the electrolytic solution of the above-mentioned present invention is used, and b in the figure is the electrolytic solution of the above-mentioned reference example. This is the case when . As can be seen from Figure 2, in reference example (b), the characteristics as a secondary battery are insufficient, whereas the electrolyte of the present invention has dramatically improved charge-discharge cycle characteristics. Recognize.
以上の説明から明らかなように、本発明によれ
ば、無機塩を溶質に、プロピレンカーボネイトと
２−メチルテトラハイドロフランの混合溶媒に用
いる事により、Li極の充放電特性が良好で、か
つ、高いLi+イオン伝導性を右するリチウム二次
電池用非水電解液を実現する事ができる。 As is clear from the above description, according to the present invention, by using an inorganic salt as a solute and a mixed solvent of propylene carbonate and 2-methyltetrahydrofuran, the charge and discharge characteristics of the Li electrode are good, and It is possible to create a non-aqueous electrolyte for lithium secondary batteries that has high Li + ion conductivity.
第１図は、本発明の実施例におけるリチウム極
の充放電効率とサイクル数の関係を示した図、第
２図はリチウムの充放電効率とサイクル数の関係
を示す図である。
FIG. 1 is a diagram showing the relationship between the charging and discharging efficiency of lithium electrodes and the number of cycles in an example of the present invention, and FIG. 2 is a diagram showing the relationship between the charging and discharging efficiency of lithium and the number of cycles.
Claims (1)
液において、前記非水電解液の有機溶媒として、
プロピレンカーボネートと２−メチルテトラハイ
ドロフランとを体積比で２：８〜７：３混合した
ものを使用した事を特徴とするリチウム二次電池
用非水電解液。1. In a non-aqueous electrolyte in which a lithium salt is dissolved in an organic solvent, as the organic solvent of the non-aqueous electrolyte,
A non-aqueous electrolyte for a lithium secondary battery, characterized by using a mixture of propylene carbonate and 2-methyltetrahydrofuran in a volume ratio of 2:8 to 7:3.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57096920A JPS58214280A (en) | 1982-06-08 | 1982-06-08 | Nonaqueous electrolyte for lithium secondary battery |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57096920A JPS58214280A (en) | 1982-06-08 | 1982-06-08 | Nonaqueous electrolyte for lithium secondary battery |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS58214280A JPS58214280A (en) | 1983-12-13 |
| JPH0477426B2 true JPH0477426B2 (en) | 1992-12-08 |
Family
ID=14177788
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP57096920A Granted JPS58214280A (en) | 1982-06-08 | 1982-06-08 | Nonaqueous electrolyte for lithium secondary battery |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS58214280A (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63148569A (en) * | 1986-12-10 | 1988-06-21 | Fuji Elelctrochem Co Ltd | Nonaqueous electrolyte cell |
| JPS63148571A (en) * | 1986-12-10 | 1988-06-21 | Fuji Elelctrochem Co Ltd | Nonaqueous electrolyte cell |
| JPS63148570A (en) * | 1986-12-10 | 1988-06-21 | Fuji Elelctrochem Co Ltd | Nonaqueous electrolyte cell |
| JPS63148572A (en) * | 1986-12-10 | 1988-06-21 | Fuji Elelctrochem Co Ltd | Nonaqueous electrolyte cell |
| US5151335A (en) * | 1991-07-29 | 1992-09-29 | The United States Of America As Represented By The Secretary Of The Air Force | Cathode material for electrochemical cells |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3468716A (en) * | 1965-10-24 | 1969-09-23 | Electrochimica Corp | Organic electrolyte electrochemical system |
| GB1474171A (en) * | 1973-05-08 | 1977-05-18 | Elkmark Holdings | Releasable couplings and loose leaf binders incorporating them |
-
1982
- 1982-06-08 JP JP57096920A patent/JPS58214280A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS58214280A (en) | 1983-12-13 |
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