JP3883726B2 - Non-aqueous electrolyte secondary battery - Google Patents
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- JP3883726B2 JP3883726B2 JP03556999A JP3556999A JP3883726B2 JP 3883726 B2 JP3883726 B2 JP 3883726B2 JP 03556999 A JP03556999 A JP 03556999A JP 3556999 A JP3556999 A JP 3556999A JP 3883726 B2 JP3883726 B2 JP 3883726B2
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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
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- 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
Description
【０００１】
【発明の属する技術分野】
本発明は、非水系電解質二次電池に関するものであり、特に充放電サイクル特性を向上させることができる非水系電解質リチウム二次電池に関するものである。
【０００２】
【従来の技術】
非水系電解質二次電池の電解液として、プロピレンカーボネート、ジメチルカーボネートなどの溶媒に、ＬｉＰＦ6 やＬｉＣｌＯ4 などの電解質溶質を溶かした非水系電解液を使用した場合、溶質や溶媒の分解に起因して非水系電解液が劣化するため、電池の充放電サイクル特性が著しく低下するという問題があった。
【０００３】
このような問題を解消するため、特開平８−２４１７３２号公報では、非水系電解液中にジオキシドチオフェンを添加し、これにより電解液の安定性の向上を図ることが提案されている。
【０００４】
【発明が解決しようとする課題】
しかしながら、リチウム二次電池においては、さらなる充放電サイクル特性の向上が望まれており、上記公報に提案されているジオキシドチオフェンの添加による方法では、未だ不十分なものであった。
【０００５】
また、充電状態の保存特性についても、その向上が従来より求められている。本発明の目的は、充放電サイクル特性に優れ、かつ充電状態の保存特性に優れた非水系電解質二次電池を提供することにある。
【０００６】
【課題を解決するための手段】
本発明の非水系電解質二次電池（以下、「本発明電池」という場合がある。）は、正極と、リチウム金属またはリチウムの吸蔵・放出が可能な物質を主材とする負極と、非水系電解質とを備える非水系電解質二次電池であり、非水系電解質が、α−トリフルオロメチル−γ−スルトン、β−トリフルオロメチル−γ−スルトン、γ−トリフルオロメチル−γ−スルトン、α−ウンデカフルオロペンチル−γ−スルトン、及びα−ヘプタフルオロプロピル−γ−スルトンから選ばれる少なくとも１種のγ−スルトン化合物を含有していることを特徴としている。
【０００８】
本発明電池においては、上記γ−スルトン化合物が非水系電解質中に添加されているので、充放電サイクル時に起こる放電容量の低下を抑制することができ、充放電サイクル特性を向上させることができる。このように放電容量の低下が抑制されるのは、非水系電解質中に上記γ−スルトン化合物が添加されることにより、負極の表面に上記γ−スルトン化合物による安定でかつ良質な被膜が形成され、これにより負極と溶媒分子の接触が断たれるためと思われる。
【０００９】
また、本発明電池によれば、充電状態の保存特性を向上させることができる。これは、上記のようなγ−スルトン化合物による被膜の形成により、負極からの電荷移行及び負極から電解質へのリチウムイオンの拡散をスムーズに行うことができ、かつ非水系電解質の劣化を防止することができるためと思われる。
【００１２】
上記のγ−スルトン化合物の具体的な構造を以下に示す。
【００１３】
【化１】
本発明において、γ−スルトン化合物の非水系電解質（非水系電解液）への添加は、少量でもその効果を発揮するが、添加量としては、非水系電解質に対して０．０１〜３．０ｍｏｌ／ｌが好ましく、さらに好ましくは、０．１〜２．０ｍｏｌ／ｌである。
【００１８】
非水系電解液の溶媒としては、エチレンカーボネート（ＥＣ）、プロピレンカーボネート（ＰＣ）、ビニレンカーボネート（ＶＣ）、ブチレンカーボネート（ＢＣ）等の有機溶媒や、これらとジメチルカーボネート（ＤＭＣ）、ジエチルカーボネート（ＤＥＣ）、エチルメチルカーボネート（ＥＭＣ）、１，２−ジエトキシエタン（ＤＥＥ）、１，２−ジメトキシエタン（ＤＭＥ）、エトキシメトキシエタン（ＥＭＥ）などの低沸点溶媒との混合溶媒が例示される。
【００１９】
なかでも、本発明で規定する添加剤との相性が良く、サイクル特性を向上させる上で特に好ましい溶媒は、一種または二種以上の環状炭酸エステルと一種または二種以上の鎖状炭酸エステルとの体積比１：４〜４：１の混合溶媒である。前記環状炭酸エステルとしては、ＥＣ、ＰＣ、ＶＣ及びＢＣの一種、鎖状炭酸エステルとしては、ＤＭＣ、ＤＥＣ及びＥＭＣの一種が例示できる。
【００２０】
非水系電解液に溶解させる溶質である電解質塩として、ＬｉＰＦ6 、ＬｉＢＦ4 及びＬｉＮ（Ｃ2 Ｆ5 ＳＯ2 ）2 から選ばれる少なくとも一種を使用することにより、電池特性を一層向上させることができる。
【００２１】
また、正極材料（活物質）としては、二酸化マンガン、Ｌｉ含有マンガン酸化物、Ｌｉ含有コバルト酸化物、Ｌｉ含有バナジウム酸化物、Ｌｉ含有ニッケル酸化物、Ｌｉ含有鉄酸化物、Ｌｉ含有クロム酸化物、Ｌｉ含有チタン酸化物等の、遷移金属を少なくとも一種含むリチウム複合酸化物が例示される。
【００２２】
さらに、負極材料（活物質）としては、金属リチウム；リチウム−アルミニウム合金、リチウム−鉛合金、リチウム−錫合金等のリチウム合金；黒鉛、コークス、有機物焼成体等の炭素材料；ＳｎＯ2 、ＳｎＯ、ＴｉＯ2 、Ｎｂ2 Ｏ3 等の電位が正極活物質に比べて卑な金属酸化物が例示される。
【００２３】
本発明は、正極と、負極と、非水系電解質とを備える非水系電解質リチウム二次電池に適用されるものであり、種々のタイプのリチウム二次電池に適用することができる。例えば、正極と負極の間にポリプロピレン製多孔膜などからなるセパレータを設けた非水系電解液二次電池に適用することができる。また、高分子電解質に非水系電解液を含浸させ、ゲル状高分子電解質とした高分子固体電解質リチウム二次電池にも適用することができる。
【００２４】
本発明の非水系電解質二次電池は、充放電サイクル特性及び保存特性に優れている。充放電サイクル特性に優れている理由としては、非水系電解質中に添加されたγ−スルトン化合物によって、負極の表面に安定な被膜が形成され、この被膜により負極と溶媒分子の接触が断たれ、このため充放電時におこる電解液の分解反応が抑制され、充放電における可逆性が向上するためと考えられる。また、充放電状態のみならず、保存状態においても電解液が安定に存在し得るため、保存特性にも優れていると考えられる。
【００２５】
【発明の実施の形態】
以下、本発明を実施例に基づいて、さらに詳細に説明するが、本発明は下記実施例により何ら限定されるものではなく、その要旨を変更しない範囲において適宜変更して実施することが可能なものである。
【００２６】
（実験１）
この実験では、非水系電解液に添加する添加剤の種類と、電池の充放電サイクル特性の関係を調べた。
【００２７】
〔正極の作製〕
ＬｉＣｏＯ2 粉末９０重量部と、人造黒鉛粉末５重量部と、ポリフッ化ビニリデン５重量部のＮ−メチル−２−ピロリドン（ＮＭＰ）溶液とを混合してスラリーを調製し、このスラリーをアルミニウム箔の両面にドクターブレード法により塗布して活物質層を形成した後、１５０℃で２時間真空乾燥して、正極を作製した。
【００２８】
〔負極の作製〕
天然黒鉛９５重量部と、ポリフッ化ビニリデン５重量部のＮＭＰ溶液とを混合してスラリーを調製し、このスラリーを銅箔の両面にドクターブレード法により塗布して炭素層を形成した後、１５０℃で２時間真空乾燥して、負極を作製した。
【００２９】
〔非水系電解液の調製〕
エチレンカーボネートとジエチルカーボネートとの等体積混合溶媒に、ＬｉＰＦ6 を０．５ｍｏｌ／ｌ溶かした溶液に、さらにγ−スルトン、α−トリフルオロメチル−γ−スルトン、β−トリフルオロメチル−γ−スルトン、γ−トリフルオロメチル−γ−スルトン、α−メチル−γ−スルトン、α，β−ジ（トリフルオロメチル）−γ−スルトン、α，α−ジ（トリフルオロメチル）−γ−スルトン、α−ウンデカフルオロペンチル−γ−スルトン、α−ヘプタフルオロプロピル−γ−スルトンを非水電解液に対して１．０ｍｏｌ／ｌとなるように添加混合して非水系電解液を調製した。
【００３０】
〔電池の作製〕
上記正極、負極及び非水系電解液を用いて、ＡＡサイズの非水系電解液二次電池（電池寸法：直径１４ｍｍ；高さ５０ｍｍ）の電池Ａ１〜Ａ９及び比較電池Ｂ１，Ｂ２を作製した。なお、いずれの電池も、セパレータとしてポリプロピレン製の多孔膜を用いた。
【００３１】
〔充放電サイクル試験〕
各電池を、室温（２５℃）にて、２００ｍＡで４．２Ｖまで定電流充電した後、２００ｍＡで３．０Ｖまで定電流放電する工程を１サイクルとする充放電サイクル試験を行った。結果を表１に示す。
【００３２】
【表１】
表１より、本発明電池Ａ２〜Ａ４及びＡ８〜Ａ９は、γ−スルトンを添加した電池Ａ１、並びに添加剤を添加していない比較電池Ｂ１及び添加剤としてジオキシドチオフェンを添加した比較電池Ｂ２に比べて、５００サイクル後の放電容量残存率が高く、サイクル特性が良いことが分かる。
【００３４】
また、フッ素置換アルキル基を有するα−トリフルオロメチル−γ−スルトンは、アルキル基を有するα−メチル−γ−スルトンに比べて、サイクル特性に優れる傾向が見られた。これは、フッ素置換アルキル基を有するγ−スルトン化合物を用いることにより、より安定な被膜形成が可能になるためと考えられ、このことから、γ−スルトンにおいて、置換基はフッ素置換アルキル基の方が好ましいと思われる。
【００３５】
（実験２）
この実験では、添加剤の非水系電解液への好適な添加量を調べた。
エチレンカーボネートとジエチルカーボネートとの等体積混合溶媒に、ＬｉＰＦ6 を０．５ｍｏｌ／ｌ溶かした溶液に、さらにα−ヘプタフルオロプロピル−γ−スルトンを非水系電解液に対して、０．００１〜４．０ｍｏｌ／ｌの添加範囲で変化させて各非水系電解液を調製した。これらの非水系電解液を使用したこと以外は実験１と同様にして電池Ａ１０〜Ａ１５を準備した。その後、各電池を前記実験１と同じ条件でサイクル試験を行った。
【００３６】
この結果を表２に示す。なお、表２には、本発明電池Ａ９及び比較電池Ｂ１の結果も表１より転記して示してある。
【００３７】
【表２】
表２に示すように、本発明電池Ａ９及びＡ１１〜Ａ１４のサイクル特性が特に良い。この事実から、α−ヘプタフルオロプロピル−γ−スルトンを非水系電解液に対して、０．０１〜３．０ｍｏｌ／ｌとなるように添加混合して使用することが好ましいことがわかる。
【００３９】
なお、α−ヘプタフルオロプロピル−γ−スルトン以外のγ−スルトン化合物を使用する場合も、添加量が０．０１〜３．０ｍｏｌ／ｌとなるように使用することが好ましいことを別途確認した。
【００４０】
（実験３）
この実験では、電解質塩の種類とサイクル特性の関係を調べた。
エチレンカーボネートとジエチルカーボネートとの等体積混合溶媒に、表３に示す種々の電解質塩を０．５ｍｏｌ／ｌ溶かした溶液に、α−ヘプタフルオロプロピル−γ−スルトンを非水電解液に対して１．０ｍｏｌ／ｌとなるように添加混合して非水系電解液を調製し、これらの非水系電解液を使用したこと以外は実験１と同様にして本発明電池Ａ１６〜Ａ２２を作製し、次いで実験１と同じ条件のサイクル試験を行った。
【００４１】
結果を表３に示す。なお、表３には、本発明電池Ａ９及び比較電池Ｂ１の結果も表１より転記して示してある。
【００４２】
【表３】
表３に示すように、本発明電池Ａ９、Ａ１６及びＡ１７のサイクル特性が特に良い。この事実から、電解質塩としては、ＬｉＰＦ6 、ＬｉＢＦ4 及びＬｉＮ（Ｃ2 Ｆ5 ＳＯ2 ）2 を使用することが好ましいことが分かる。
【００４４】
（実験４）
この実験では、各電池の充電保存特性を調べた。
本発明電池Ａ１〜Ａ２２及び比較電池Ｂ１，Ｂ２について、２００ｍＡで４．２Ｖまで充電した後、２００ｍＡで３．０Ｖまで充電した。その後、２００ｍＡで４．２Ｖまで充電し、この状態で６０℃、２０日間保存試験を行った。また、各電池の保存に伴う放電容量の変化は２００ｍＡで３．０Ｖまで放電して測定した。
【００４５】
図１は、本発明電池Ａ１〜Ａ２２及び比較電池Ｂ１，Ｂ２について、各電池の保存後の放電容量を、縦軸に放電容量（ｍＡｈ）、横軸に保存期間（日）をとって示したものである。
【００４６】
図１に示すように、本発明電池Ａ１〜Ａ２２では比較電池Ｂ１，Ｂ２に比べて、保存後の放電容量が大きく、保存特性に優れていることが分かる。これは、γ−スルトン化合物が、負極と電解液の界面に被膜を形成し、この被膜によって保存状態における電解液が安定化するためと考えられる。
【００４７】
【発明の効果】
本発明によれば、γ−スルトン化合物を非水系電解質中に含有させることにより、充放電サイクル特性及び保存特性に優れた非水系電解質二次電池とすることができる。
【図面の簡単な説明】
【図１】本発明電池及び比較電池の保存特性を示す図。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a non-aqueous electrolyte secondary battery, and more particularly to a non-aqueous electrolyte lithium secondary battery capable of improving charge / discharge cycle characteristics.
[0002]
[Prior art]
When a non-aqueous electrolyte solution in which an electrolyte solute such as LiPF 6 or LiClO 4 is dissolved in a solvent such as propylene carbonate or dimethyl carbonate is used as the electrolyte solution of the non-aqueous electrolyte secondary battery, it is caused by decomposition of the solute or solvent. As a result, the non-aqueous electrolyte deteriorates, so that there is a problem that the charge / discharge cycle characteristics of the battery are remarkably lowered.
[0003]
In order to solve such problems, Japanese Patent Application Laid-Open No. 8-241732 proposes to add dioxide thiophene to a non-aqueous electrolyte solution, thereby improving the stability of the electrolyte solution.
[0004]
[Problems to be solved by the invention]
However, in lithium secondary batteries, further improvement in charge / discharge cycle characteristics is desired, and the method based on the addition of dioxide thiophene proposed in the above publication is still insufficient.
[0005]
Further, improvement in the storage characteristics of the charged state has been demanded conventionally. An object of the present invention is to provide a non-aqueous electrolyte secondary battery that is excellent in charge / discharge cycle characteristics and excellent in charge state storage characteristics.
[0006]
[Means for Solving the Problems]
The non-aqueous electrolyte secondary battery of the present invention (hereinafter sometimes referred to as “the present invention battery”) includes a positive electrode, a negative electrode mainly composed of lithium metal or a material capable of occluding and releasing lithium, and a non-aqueous battery. A non-aqueous electrolyte secondary battery comprising an electrolyte, wherein the non-aqueous electrolyte is α-trifluoromethyl-γ-sultone, β-trifluoromethyl-γ-sultone, γ-trifluoromethyl-γ-sultone, α- It is characterized by containing at least one γ-sultone compound selected from undecafluoropentyl-γ-sultone and α-heptafluoropropyl-γ-sultone .
[0008]
In the battery of the present invention, since the γ-sultone compound is added to the nonaqueous electrolyte, it is possible to suppress a decrease in discharge capacity that occurs during the charge / discharge cycle, and to improve the charge / discharge cycle characteristics. In this way, the decrease in discharge capacity is suppressed by adding the γ-sultone compound to the non-aqueous electrolyte, thereby forming a stable and high-quality film with the γ-sultone compound on the surface of the negative electrode. This is considered to be because the contact between the negative electrode and the solvent molecule is cut off.
[0009]
Moreover, according to the battery of the present invention, it is possible to improve the storage characteristics of the charged state. This is because the formation of a coating film with the above-described γ-sultone compound can smoothly perform charge transfer from the negative electrode and diffusion of lithium ions from the negative electrode to the electrolyte, and prevent deterioration of the non-aqueous electrolyte. It seems to be possible.
[0012]
The specific structure of the above γ-sultone compound is shown below.
[0013]
[Chemical 1]
In the present invention, the addition of the γ-sultone compound to the non-aqueous electrolyte (non-aqueous electrolyte) exhibits its effect even in a small amount, but the addition amount is 0.01 to 3.0 mol with respect to the non-aqueous electrolyte. / L is preferable, and more preferably 0.1 to 2.0 mol / l.
[0018]
Examples of the solvent for the non-aqueous electrolyte include organic solvents such as ethylene carbonate (EC), propylene carbonate (PC), vinylene carbonate (VC), butylene carbonate (BC), and dimethyl carbonate (DMC) and diethyl carbonate (DEC). ), Ethyl methyl carbonate (EMC), 1,2-diethoxyethane (DEE), 1,2-dimethoxyethane (DME), mixed solvents with low-boiling solvents such as ethoxymethoxyethane (EME).
[0019]
Among them, the compatibility with the additives defined in the present invention is good, and particularly preferred solvents for improving the cycle characteristics are one or two or more cyclic carbonates and one or two or more chain carbonates. A mixed solvent having a volume ratio of 1: 4 to 4: 1. Examples of the cyclic carbonate ester include EC, PC, VC, and BC, and examples of the chain carbonate ester include DMC, DEC, and EMC.
[0020]
By using at least one selected from LiPF 6 , LiBF 4, and LiN (C 2 F 5 SO 2 ) 2 as an electrolyte salt that is a solute dissolved in the nonaqueous electrolytic solution, the battery characteristics can be further improved. .
[0021]
Further, as the positive electrode material (active material), manganese dioxide, Li-containing manganese oxide, Li-containing cobalt oxide, Li-containing vanadium oxide, Li-containing nickel oxide, Li-containing iron oxide, Li-containing chromium oxide, Examples thereof include lithium composite oxides containing at least one transition metal such as Li-containing titanium oxide.
[0022]
Furthermore, as the negative electrode material (active material), metallic lithium; lithium alloys such as lithium-aluminum alloy, lithium-lead alloy, and lithium-tin alloy; carbon materials such as graphite, coke, and organic fired bodies; SnO 2 , SnO, Examples of the metal oxide are TiO 2 , Nb 2 O 3, etc., which have a lower potential than the positive electrode active material.
[0023]
The present invention is applied to a non-aqueous electrolyte lithium secondary battery including a positive electrode, a negative electrode, and a non-aqueous electrolyte, and can be applied to various types of lithium secondary batteries. For example, it can be applied to a non-aqueous electrolyte secondary battery in which a separator made of a polypropylene porous film or the like is provided between a positive electrode and a negative electrode. Further, the present invention can also be applied to a polymer solid electrolyte lithium secondary battery in which a polymer electrolyte is impregnated with a non-aqueous electrolyte solution to form a gel polymer electrolyte.
[0024]
The nonaqueous electrolyte secondary battery of the present invention is excellent in charge / discharge cycle characteristics and storage characteristics. The reason why the charge / discharge cycle characteristics are excellent is that a stable film is formed on the surface of the negative electrode by the γ-sultone compound added in the non-aqueous electrolyte, and the contact between the negative electrode and solvent molecules is cut off by this film, For this reason, it is thought that the decomposition reaction of the electrolyte solution that occurs during charging and discharging is suppressed, and the reversibility in charging and discharging is improved. Further, since the electrolyte solution can exist stably not only in the charge / discharge state but also in the storage state, it is considered that the storage characteristics are excellent.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in more detail on the basis of examples. However, the present invention is not limited to the following examples in any way, and can be appropriately modified and implemented without departing from the scope of the present invention. Is.
[0026]
(Experiment 1)
In this experiment, the relationship between the type of additive added to the non-aqueous electrolyte and the charge / discharge cycle characteristics of the battery was examined.
[0027]
[Production of positive electrode]
A slurry is prepared by mixing 90 parts by weight of LiCoO 2 powder, 5 parts by weight of artificial graphite powder, and 5 parts by weight of polyvinylidene fluoride with N-methyl-2-pyrrolidone (NMP) solution. An active material layer was formed on both surfaces by a doctor blade method, and then vacuum dried at 150 ° C. for 2 hours to produce a positive electrode.
[0028]
(Production of negative electrode)
A slurry was prepared by mixing 95 parts by weight of natural graphite and 5 parts by weight of an NMP solution of polyvinylidene fluoride. The slurry was applied to both sides of a copper foil by a doctor blade method to form a carbon layer, and then 150 ° C. And vacuum drying for 2 hours to produce a negative electrode.
[0029]
(Preparation of non-aqueous electrolyte)
In a solution obtained by dissolving 0.5 mol / l LiPF 6 in an equal volume mixed solvent of ethylene carbonate and diethyl carbonate, γ-sultone, α-trifluoromethyl-γ-sultone, β-trifluoromethyl-γ-sultone is further added. , Γ-trifluoromethyl-γ-sultone, α-methyl-γ-sultone, α, β-di (trifluoromethyl) -γ-sultone, α, α-di (trifluoromethyl) -γ-sultone, α -Undecafluoropentyl-γ-sultone and α-heptafluoropropyl-γ-sultone were added and mixed at 1.0 mol / l with respect to the nonaqueous electrolyte solution to prepare a nonaqueous electrolyte solution.
[0030]
[Production of battery]
The positive electrode using the negative electrode and the nonaqueous electrolyte, the nonaqueous electrolyte secondary battery of AA size:; was produced batteries A1~A9 and comparative batteries B1, B2 of the (cell size diameter 14mm height 50 mm). In all the batteries, a polypropylene porous film was used as a separator.
[0031]
[Charge / discharge cycle test]
Each battery was charged at a constant current to 4.2 V at 200 mA at room temperature (25 ° C.), and then subjected to a charge / discharge cycle test in which the step of discharging at a constant current to 3.0 V at 200 mA was one cycle. The results are shown in Table 1.
[0032]
[Table 1]
From Table 1, the batteries A 2 to A 4 and A 8 to A 9 of the present invention are the battery A 1 to which γ-sultone is added, the comparative battery B 1 to which no additive is added, and the comparative battery to which dioxide thiophene is added as an additive. It can be seen that the discharge capacity remaining rate after 500 cycles is high and the cycle characteristics are good compared to B2.
[0034]
Moreover, the tendency for α-trifluoromethyl-γ-sultone having a fluorine-substituted alkyl group to be excellent in cycle characteristics was seen compared to α-methyl-γ-sultone having an alkyl group. This is considered to be because a more stable film can be formed by using a γ-sultone compound having a fluorine-substituted alkyl group. From this, in γ-sultone, the substituent is a fluorine-substituted alkyl group. Seems to be preferable.
[0035]
(Experiment 2)
In this experiment, the preferred amount of additive added to the non-aqueous electrolyte was examined.
In a solution obtained by dissolving 0.5 mol / l LiPF 6 in an equal volume mixed solvent of ethylene carbonate and diethyl carbonate, α-heptafluoropropyl-γ-sultone is further added to 0.001 to 4 with respect to the non-aqueous electrolyte. Each non-aqueous electrolyte was prepared by changing the addition range of 0.0 mol / l. Batteries A10 to A15 were prepared in the same manner as in Experiment 1 except that these nonaqueous electrolytic solutions were used. Thereafter, each battery was subjected to a cycle test under the same conditions as in Experiment 1.
[0036]
The results are shown in Table 2. In Table 2, the results of the battery A9 of the present invention and the comparative battery B1 are also transferred from Table 1.
[0037]
[Table 2]
As shown in Table 2, the cycle characteristics of the batteries A9 and A11 to A14 of the present invention are particularly good. From this fact, it can be seen that α-heptafluoropropyl-γ-sultone is preferably added and mixed so as to be 0.01 to 3.0 mol / l with respect to the nonaqueous electrolytic solution.
[0039]
In addition, when using (gamma) -sultone compounds other than (alpha) -heptafluoropropyl-gamma-sultone, it confirmed separately that it was preferable to use so that addition amount might be 0.01-3.0 mol / l.
[0040]
(Experiment 3)
In this experiment, the relationship between the type of electrolyte salt and cycle characteristics was examined.
Α-heptafluoropropyl-γ-sultone was added to a non-aqueous electrolyte solution in an amount of 0.5 mol / l of various electrolyte salts shown in Table 3 in an equal volume mixed solvent of ethylene carbonate and diethyl carbonate. The present invention batteries A16 to A22 were prepared in the same manner as in Experiment 1 except that these nonaqueous electrolytes were prepared by adding and mixing to 0.0 mol / l, and then the experiments were performed. A cycle test under the same conditions as 1 was performed.
[0041]
The results are shown in Table 3. In Table 3, the results of the battery A9 of the present invention and the comparative battery B1 are also transferred from Table 1.
[0042]
[Table 3]
As shown in Table 3, the cycle characteristics of the batteries A9, A16 and A17 of the present invention are particularly good. From this fact, it can be seen that it is preferable to use LiPF 6 , LiBF 4 and LiN (C 2 F 5 SO 2 ) 2 as the electrolyte salt.
[0044]
(Experiment 4)
In this experiment, the charge storage characteristics of each battery were examined.
About this invention battery A1-A22 and comparative battery B1, B2, after charging to 4.2V at 200 mA, it charged to 3.0V at 200 mA. Thereafter, the battery was charged at 200 mA to 4.2 V, and a storage test was performed in this state at 60 ° C. for 20 days. Moreover, the change of the discharge capacity accompanying storage of each battery was measured by discharging to 200 V at 200 mA.
[0045]
FIG. 1 shows the discharge capacity after storage of each of the batteries A1 to A22 of the present invention and the comparative batteries B1 and B2, the discharge capacity (mAh) on the vertical axis and the storage period (days) on the horizontal axis. Is.
[0046]
As shown in FIG. 1, it can be seen that the batteries A1 to A22 of the present invention have a large discharge capacity after storage and excellent storage characteristics compared to the comparative batteries B1 and B2. This is presumably because the γ-sultone compound forms a coating at the interface between the negative electrode and the electrolytic solution, and the coating stabilizes the electrolytic solution in the storage state.
[0047]
【The invention's effect】
According to the present invention, a non-aqueous electrolyte secondary battery excellent in charge / discharge cycle characteristics and storage characteristics can be obtained by including a γ-sultone compound in the non-aqueous electrolyte.
[Brief description of the drawings]
FIG. 1 is a graph showing storage characteristics of a battery of the present invention and a comparative battery.
Claims (4)
前記非水系電解質が、α−トリフルオロメチル−γ−スルトン、β−トリフルオロメチル−γ−スルトン、γ−トリフルオロメチル−γ−スルトン、α−ウンデカフルオロペンチル−γ−スルトン、及びα−ヘプタフルオロプロピル−γ−スルトンから選ばれる少なくとも１種のγ−スルトン化合物を含有していることを特徴とする非水系電解質二次電池。 In a non-aqueous electrolyte secondary battery comprising a positive electrode, a negative electrode mainly composed of lithium metal or a substance capable of occluding and releasing lithium, and a non-aqueous electrolyte,
The non-aqueous electrolyte comprises α-trifluoromethyl-γ-sultone, β-trifluoromethyl-γ-sultone, γ-trifluoromethyl-γ-sultone, α-undecafluoropentyl-γ-sultone, and α- A non-aqueous electrolyte secondary battery comprising at least one γ-sultone compound selected from heptafluoropropyl-γ-sultone .
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| JP03556999A JP3883726B2 (en) | 1999-02-15 | 1999-02-15 | Non-aqueous electrolyte secondary battery |
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| Application Number | Priority Date | Filing Date | Title |
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| JP03556999A JP3883726B2 (en) | 1999-02-15 | 1999-02-15 | Non-aqueous electrolyte secondary battery |
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| JP3883726B2 true JP3883726B2 (en) | 2007-02-21 |
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| JP4693248B2 (en) * | 2001-01-09 | 2011-06-01 | 三井化学株式会社 | Polymer solid electrolyte and secondary battery |
| JP4573474B2 (en) * | 2001-08-06 | 2010-11-04 | 日立マクセル株式会社 | Non-aqueous secondary battery |
| JP4618399B2 (en) | 2002-06-11 | 2011-01-26 | 日本電気株式会社 | Secondary battery electrolyte and secondary battery using the same |
| US7608364B2 (en) | 2003-01-10 | 2009-10-27 | Nec Corporation | Lithium ion secondary battery |
| US7662519B2 (en) | 2003-09-16 | 2010-02-16 | Nec Corporation | Non-aqueous electrolyte secondary battery |
| JP4433163B2 (en) * | 2004-02-13 | 2010-03-17 | 日本電気株式会社 | Electrolytic solution for lithium secondary battery and lithium secondary battery using the same |
| JP5181430B2 (en) * | 2005-05-26 | 2013-04-10 | ソニー株式会社 | Secondary battery |
| JP2008181884A (en) * | 2008-02-18 | 2008-08-07 | Sony Corp | Nonaqueous electrolyte battery |
| JP5169400B2 (en) | 2008-04-07 | 2013-03-27 | Ｎｅｃエナジーデバイス株式会社 | Nonaqueous electrolyte and nonaqueous electrolyte secondary battery using the same |
| CN103283076A (en) * | 2011-03-28 | 2013-09-04 | 松下电器产业株式会社 | Nonaqueous electrolyte and nonaqueous electrolyte secondary battery using same |
| CN102790236A (en) * | 2011-05-18 | 2012-11-21 | 张家港市国泰华荣化工新材料有限公司 | Non-aqueous electrolyte solution of fluorine-containing compound |
| JP5598457B2 (en) * | 2011-10-31 | 2014-10-01 | ソニー株式会社 | Secondary battery and electronic equipment |
| CN104756288B (en) | 2012-10-30 | 2018-06-29 | 日本电气株式会社 | Lithium secondary battery |
| AU2014226999B2 (en) | 2013-03-05 | 2016-10-27 | Nec Corporation | Lithium secondary battery |
| JP6081339B2 (en) * | 2013-10-11 | 2017-02-15 | オートモーティブエナジーサプライ株式会社 | Nonaqueous electrolyte secondary battery |
| EP3091602A4 (en) * | 2014-03-27 | 2017-07-05 | Daikin Industries, Ltd. | Electrolyte and electrochemical device |
| CN114552006A (en) * | 2022-02-18 | 2022-05-27 | 香河昆仑新能源材料股份有限公司 | Electrolyte additive composition and application |
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