JP3599372B2 - Organic sulfonic acid lithium salt - Google Patents

Description

融点：４５３℃（ＤＳＣ（セイコー電子（株）：Ｓ−５０００）で測定、昇温速度１５℃／分）。
【００１２】

【００１３】
【実施例２】
〔アルミニウム陽極酸化電流の測定〕
１，１，２，３，３，３−ヘキサフルオロ−ｎ−プロパンスルホン酸リチウムの濃度１モル／ｌのプロピレンカーボネート溶液を電解液とし、作用電極をアルミニウム（市販のアルミ箔）、対電極及び参照電極をリチウム金属としたセルでアルミニウムを４．０Ｖ（ｖｓ．Ｌｉ金属）の電位に保持したとき、電極間を２１ｍＡ・ｃｍ^−２の電流が流れた。
【００１４】
【比較例１】
トリフルオロメタンスルホン酸リチウム（Ａｌｄｒｉｃｈ社製）の濃度１モル／ｌのプロピレンカーボネート溶液を電解液とし、作用電極をアルミニウム（市販のアルミ箔）、対電極及び参照電極をリチウム金属としたセルでアルミニウムを４．０Ｖ（ｖｓ．Ｌｉ金属）の電位に保持したとき、電極間を２１０ｍＡ・ｃｍ^−２の電流が流れた。
【００１５】
実施例２の電解液での電流値は比較例１の電解液での値の１／１０であり、実施例１の電解液中ではアルミニウムの腐食速度は比較例１の電解液中の１／１０となることを示している。
【００１６】
【実施例３】
図２に示す円筒型非水電解液電池を下記のようにして作製した。
まず、ＬｉＣｏＯ_２ をボールミルで平均粒径３μｍに粉砕した後、この粉末１重量部に対しグラファイト０．０２５重量部、アセチレンブラック０．０２５重量部、結合剤としてポリフッ化ビニリデン０．０２重量部を加え、ジメチルホルムアミドを用いてペースト状にしたものを、厚さ１５μｍのアルミ箔の片面に乾燥膜厚が１００μｍになるように塗布して正極１を作製した。
【００１７】
一方、市販の石油系ニードルコークス（興亜石油社製、ＫＯＡ−ＳＪ Ｃｏｋｅ）をボールミルで平均粒径１０μｍに粉砕した。このニードルコークスのＢＥＴ表面積、真密度、Ｘ線回折より得られる面間隔ｄ_０．０２，Ｌｃ_{（００２）} はそれぞれ、１１ｍ^２ ・ｇ^−１、２．１３ｇ・ｃｍ^−３，３．４４Å、５２Åであった。この粉末１重量部に対して結合剤としてポリフッ化ビニリデン０．０５重量部を加え、ジメチルホルムアミドを用いてペースト状にし、厚さ１０μｍの銅箔の片面に乾燥膜厚が１３０μｍになるように塗布して負極２を作製した。なお、正極１及び負極２には、集電を行うためのアルミニウム製の正極リード端子３、銅製の負極リード端子４をそれぞれ溶接した。
【００１８】
そして、正極１と負極２との間に、ポリエチレン製の微多孔膜からなるセパレータ５を介在させて互いに積層し、多数回巻回して、渦巻き型の電極体を作製した。さらに、この渦巻き型の電極体をＳＵＳ製電池容器６中に収納した。負極リード端子４を電池容器６の内底部にスポット溶接により接続し、正極リード端子３は電池封口板７に同様にして接続した。
【００１９】
次に、この電極体が収納された電池缶容器６中に、プロピレンカーボネート、エチレンカーボネート、γ−ブチロラクトンを体積比１対１対２で混合した混合溶媒に、電解質として本発明の化合物１，１，２，３，３，３−ヘキサフルオロ−ｎ−プロパンスルホン酸リチウムを１．０ｍｏｌ・ｄｍ^−３になるように溶解させて調整した電解液を注液し、該電池容器６と前記電池封口板７とをポリプロピレン製パッキング８を介し、嵌合することにより密封し、外径２０ｍｍ、５０ｍｍの円筒型非水電解液電池を作製した。
【００２０】
この電池を、充放電電流１Ａ、充電終止電圧４．２Ｖ、放電終止電圧２．７Ｖ、で室温（２０℃）において充放電試験を行ったところ、１サイクルめの放電容量１．０Ａｈ、５０サイクルめの放電容量保持率（５０サイクルめの放電容量を１サイクルめの放電容量で割った百分率）７５％という結果を得た。
【００２１】
【発明の効果】
本発明により、有機電解質として有用な新規化合物１，１，２，３，３，３−ヘキサフルオロ−ｎ−プロパンスルホン酸リチウムを得ることができる。本発明の化合物は電解質としてアルミニウムの腐食が起こりにくい非水系電解液を提供する。
【図面の簡単な説明】
【図１】本発明の化合物の赤外吸収スペクトルである。
【図２】本発明の実施例３で用いた非水電解液電池の縦断面図である。
【符号の説明】
１．帯状正極
２．帯状負極
３．正極リード端子
４．負極リード端子
５．セパレータ
６．電池容器
７．電池封口板
８．パッキング
９．絶縁板[0001]
[Industrial applications]
The present invention relates to a novel compound, lithium 1,1,2,3,3,3-hexafluoro-n-propanesulfonate. The present compound is useful as an electrolyte of a non-aqueous electrolyte.
[0002]
[Prior art]
Conventionally, lithium trifluoromethanesulfonate has been used as an organic electrolyte of a non-aqueous electrolyte. Lithium trifluoromethanesulfonate is characterized by having a higher solubility in nonaqueous electrolyte solvents such as carbonate and lactone than inorganic electrolytes such as lithium tetrafluorophosphate and lithium hexafluorophosphate. However, there is a drawback that aluminum cannot be used as a material when lithium trifluoromethanesulfonate is used as an electrolyte, because aluminum is corroded by anodic oxidation.
[0003]
[Problems to be solved by the invention]
An object of the present invention is to provide a compound useful as an organic electrolyte of a non-aqueous electrolytic solution in which corrosion of aluminum does not easily occur, and to provide a non-aqueous electrolytic solution using the compound as an electrolyte. It is still another object of the present invention to provide a battery comprising the electrolyte and an electrode using aluminum as a current collector.
[0004]
[Means for Solving the Problems]
As a result of intensive studies, the present inventors have found that lithium 1,1,2,3,3,3-hexafluoro-n-propanesulfonate is a compound that solves the above-mentioned problems, and have reached the present invention.
Hereinafter, the present invention will be described in detail.
[0005]
Lithium 1,1,2,3,3,3-hexafluoro-n-propanesulfonate (CF ₃ CHFCF ₂ SO ₃ Li) which is a compound of the present invention is a novel compound. Although the synthesis method is not particularly limited, as an example, sodium 1,1,2,3,3,3-hexafluoro-n-propanesulfonate (NaHSO ₃₎ generated by an addition reaction between sodium bisulfite and hexafluoropropylene is used. + CF ₂ = CF-CF ₃ → CF ₃ CHFCF ₂ SO ₃ Na) is hydrolyzed and then reacted with lithium carbonate.
[0006]
The use of the compound 1,1,2,3,3,3-lithium hexafluoro-n-propanesulfonate of the present invention is specifically intended for use in electrolytes of non-aqueous electrolytes for primary or secondary batteries, and for organic synthesis reactions. And a catalyst.
When the compound is used as the electrolyte of the non-aqueous electrolyte, the solvent of the non-aqueous electrolyte is not particularly limited as long as it is an aprotic polar solvent that can dissolve the compound, and includes, for example, carbonates, esters, Lactones, ethers, nitriles, amides, sulfones and the like can be used, and among them, carbonates, esters, lactones and ethers are preferable. Further, not only a single solvent but also a mixture of two or more solvents may be used. The electrolyte concentration of the non-aqueous electrolyte is preferably 0.1 mol · dm ⁻³ or more and a saturation concentration or less, more preferably 0.5 mol · dm ⁻³ or more and a saturation concentration or more and a saturation concentration or less. If it is less than 0.1 mol · dm ⁻³ , the conductivity of the electrolytic solution is low, which is not preferable.
[0007]
As the battery comprising the nonaqueous electrolyte and an electrode having aluminum as a current collector, for example, a copper foil as a current collector, a negative electrode mainly composed of carbon capable of absorbing lithium ions, and an aluminum foil as a current collector And a lithium ion secondary battery comprising a positive electrode mainly composed of a lithium-containing transition metal chalcogen compound.
[0008]
【Example】
Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to the scope of the examples.
[0009]
Embodiment 1
1: sodium bisulfite pressure vessel addition reaction 1,000ml of sodium bisulfite and hexafluoropropylene (NaHSO ₃₎ 80g, sodium tetraborate decahydrate _{(Na 2 B 4 O 7 ·} 10H 2 O) 36. 7 g, 160 ml of pure water and 120 g of hexafluoropropylene were added and reacted at 120 ° C. for 110 hours. The reaction solution was filtered, the filtrate was dehydrated to dryness under reduced pressure, 300 ml of ethanol was added, and the mixture was refluxed for 3 hours. The resulting insoluble solid was separated by filtration. to give 3,3-hexafluoropropane -n--propane sulfonic acid _{(CF 3 CHFCF 2 SO 3 Na} ). The yield was 18.0%.
2: Hydrolysis of sodium 1,1,2,3,3,3-hexafluoro-n-propanesulfonate 1,1,2,3,3,3 synthesized in the above 1 in a 300 ml four-necked flask. After adding 18.0 g of sodium hexafluoro-n-propanesulfonate and 40 ml of 35% sulfuric acid and stirring at 15 ° C. for 2 hours, the mixture was diluted with 80 ml of pure water and extracted three times with 100 ml of diethyl ether. The solvent was removed from the ether phase to obtain 15.0 g of 1,1,2,3,3,3-hexafluoro-n-propanesulfonic acid monohydrate (CF ₃ CHFCF ₂ SO ₃ H.H ₂ O). Was. To this monohydrate, 15.5 ml of thionyl chloride SOCl ₂ was added, and the temperature was raised from room temperature to 40 ° C. with stirring to perform dehydration, followed by distillation under reduced pressure and a fraction at 70 to 72 ° C. at 2 mmHg. 83 g were collected. 0.021 mole of 1,1,2,3,3,3-hexafluoro-n-propanesulfonic acid was obtained, and the yield was about 30%.
3: Synthesis of lithium 1,1,2,3,3,3-hexafluoro-n-propanesulfonic acid 1,1,2,3,3,3-hexafluoro-n-propanesulfonic acid 4 was added to a 50 ml flask. 0.83 g, 5 ml of pure water and 0.783 g of lithium carbonate were stirred at room temperature for 2 hours, dehydrated and dried under reduced pressure, and dried with 1,1,2,3,3,3-hexafluoro-n-propanesulfonic acid. 4.74 g of lithium were obtained. The yield was 95.7%.
[0010]
FIG. 1 shows an infrared absorption spectrum of lithium 1,1,2,3,3,3-hexafluoro-n-propanesulfonate CF ₃ CHFCF ₂ SO ₃ Li. [3,005 cm ^-1 (CH); 1,640 cm ^-1 (S = O); 1,240 cm ^-1 (CF)]
Other physical properties are also shown below.
[0011]

Melting point: 453 ° C. (measured by DSC (Seiko Denshi Co., Ltd .: S-5000), heating rate 15 ° C./min).
[0012]

[0013]
Embodiment 2
[Measurement of aluminum anodic oxidation current]
A propylene carbonate solution having a concentration of lithium 1,1,2,3,3,3-hexafluoro-n-propanesulfonate having a concentration of 1 mol / l was used as an electrolyte, and a working electrode was aluminum (a commercially available aluminum foil), a counter electrode and When aluminum was held at a potential of 4.0 V (vs. Li metal) in a cell in which the reference electrode was lithium metal, a current of 21 mA · cm ⁻² flowed between the electrodes.
[0014]
[Comparative Example 1]
A 1 mol / l propylene carbonate solution of lithium trifluoromethanesulfonate (manufactured by Aldrich) was used as an electrolyte, aluminum was used as a working electrode (a commercially available aluminum foil), and lithium was used as a counter electrode and a reference electrode. When maintained at a potential of 4.0 V (vs. Li metal), a current of 210 mA · cm ⁻² flowed between the electrodes.
[0015]
The current value of the electrolytic solution of Example 2 was 1/10 of the value of the electrolytic solution of Comparative Example 1, and the corrosion rate of aluminum in the electrolytic solution of Example 1 was 1/100 that of the electrolytic solution of Comparative Example 1. 10 is shown.
[0016]
Embodiment 3
The cylindrical nonaqueous electrolyte battery shown in FIG. 2 was produced as follows.
First, LiCoO ₂ was pulverized with a ball mill to an average particle size of 3 μm, and 0.025 parts by weight of graphite, 0.025 parts by weight of acetylene black, and 0.02 parts by weight of polyvinylidene fluoride as a binder were added to 1 part by weight of the powder. In addition, a paste made using dimethylformamide was applied to one surface of an aluminum foil having a thickness of 15 μm so that the dry film thickness became 100 μm, to produce a positive electrode 1.
[0017]
On the other hand, a commercially available petroleum needle coke (KOA-SJ Coke, manufactured by Koa Oil Co., Ltd.) was pulverized with a ball mill to an average particle size of 10 μm. The needle coke has a BET surface area, a true density, and a plane spacing d _0.02 , Lc ₍₀₀₂₎ obtained from X-ray diffraction, of 11 m ² · g ⁻¹ , 2.13 g · cm ⁻³ , 3.44 ° and 52 °, respectively. Met. To 1 part by weight of this powder, add 0.05 parts by weight of polyvinylidene fluoride as a binder, form a paste using dimethylformamide, and apply it to one side of a 10-μm-thick copper foil to a dry film thickness of 130 μm. Thus, a negative electrode 2 was produced. The positive electrode 1 and the negative electrode 2 were welded with a positive electrode lead terminal 3 made of aluminum and a negative electrode lead terminal 4 made of copper for current collection.
[0018]
Then, a separator 5 made of a microporous polyethylene film was interposed between the positive electrode 1 and the negative electrode 2, laminated one on another, and wound many times to produce a spiral electrode body. Further, the spiral electrode body was accommodated in a battery container 6 made of SUS. The negative electrode lead terminal 4 was connected to the inner bottom of the battery container 6 by spot welding, and the positive electrode lead terminal 3 was connected to the battery sealing plate 7 in the same manner.
[0019]
Next, a compound 1, 1 of the present invention was used as an electrolyte in a mixed solvent obtained by mixing propylene carbonate, ethylene carbonate, and γ-butyrolactone at a volume ratio of 1: 1 to 2 in the battery can 6 containing the electrode body. , 2,3,3,3-Lithium hexafluoro-n-propanesulfonate was dissolved and adjusted to 1.0 mol · dm ^-3 , and an electrolyte solution was injected, and the battery container 6 and the battery cap were sealed. The plate 7 was sealed by fitting it through a polypropylene packing 8 to produce a cylindrical nonaqueous electrolyte battery having an outer diameter of 20 mm and 50 mm.
[0020]
The battery was subjected to a charge / discharge test at room temperature (20 ° C.) at a charge / discharge current of 1 A, a charge end voltage of 4.2 V, and a discharge end voltage of 2.7 V. As a result, the first cycle had a discharge capacity of 1.0 Ah and 50 cycles. The discharge capacity retention rate (percentage of the discharge capacity at the 50th cycle divided by the discharge capacity at the first cycle) was 75%.
[0021]
【The invention's effect】
According to the present invention, a novel compound 1,1,2,3,3,3-hexafluoro-n-propanesulfonate useful as an organic electrolyte can be obtained. The compound of the present invention provides a non-aqueous electrolyte which is less likely to cause corrosion of aluminum as an electrolyte.
[Brief description of the drawings]
FIG. 1 is an infrared absorption spectrum of the compound of the present invention.
FIG. 2 is a longitudinal sectional view of a nonaqueous electrolyte battery used in Example 3 of the present invention.
[Explanation of symbols]
1. 1. Strip-shaped positive electrode 2. Strip negative electrode Positive electrode lead terminal4. Negative electrode lead terminal5. Separator 6. Battery container 7. 7. Battery sealing plate Packing 9. Insulating plate

Claims (2)

Lithium 1,1,2,3,3,3-hexafluoro-n-propanesulfonate. A non-aqueous electrolyte containing lithium 1,1,2,3,3,3-hexafluoro-n-propanesulfonate.

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