本文選題：鋰離子電池　切入點：草酸二氟硼酸鋰　出處：《蘭州理工大學(xué)》2014年碩士論文　論文類型：學(xué)位論文

【摘要】：目前,鋰離子電池的電解液體系主要是由LiPF6電解質(zhì)鋰鹽和碳酸酯類有機溶劑構(gòu)成。但LiPF6易分解及潮解,因此研發(fā)新型電解質(zhì)鋰鹽是電池領(lǐng)域的一個研究熱點。 本文利用一種新方法實現(xiàn)了草酸二氟硼酸鋰(LiODFB)和LiBF4兩種電解質(zhì)鋰鹽的聯(lián)產(chǎn),相比于以前的制備方法更加經(jīng)濟、簡單,且產(chǎn)率更高�；贚iODFB的新型電解液體系0.9mol L1LiODFB-SL(環(huán)丁砜)/DMS(亞硫酸二甲酯)的氧化分解電勢高于5.5V,有望成為一種新型的5V高電壓鋰離子電池的電解液體系。當(dāng)應(yīng)用于MCMB(中間相炭微球)/Li.LiFeP04/Li電池時,0.9mol L-1LiODFB-SL/DMS電解液體系在電極材料表面形成了穩(wěn)定、有效的界面膜,提高了電池的循環(huán)性能、倍率性能等。 作為上述研究結(jié)果的延伸,實驗中進一步將LiODFB中的草酸根基團用含硫基團所替代,首次制備出了硫酸二氟硼酸鋰(LiBF3SO4),并對其基本物理性質(zhì)進行了研究。進一步的，，以LiPF�；娊庖后w系作為參照物,系統(tǒng)研究了LiBF2SO4基電解液的電化學(xué)性能。研究表明,得益于LiBF2SO4對電極/電解液界面膜的改善作用,1.0mol L-1LiBF2SO4-EC(碳酸乙烯酯)/DMC(碳酸二甲酯)(1：1,體積比)電解液體系組裝的實驗電池具有良好的電化學(xué)穩(wěn)定性,穩(wěn)定的循環(huán)性能和優(yōu)異的倍率性能。特別是在80℃時,LiBF2SO4-EC/DMC電解液體系仍表現(xiàn)出了良好的熱穩(wěn)定性,穩(wěn)定的循環(huán)性能以及良好的倍率性能。 這些工作,既建立起了具有實際應(yīng)用前景的新型電解液體系,又為新型鋰鹽的設(shè)計、研發(fā)提供了指導(dǎo)。
[Abstract]:At present, the electrolyte system of lithium-ion battery is mainly composed of lithium salt of LiPF6 electrolyte and organic solvent of carbonate, but LiPF6 is easy to be decomposed and deliquescent, so the research and development of new electrolyte lithium salt is a research hotspot in battery field. In this paper, a new method is used to realize the co-production of LiODFB (LiODFB) and LiBF4 electrolyte lithium salts, which is more economical and simpler than the previous preparation method. The new electrolyte system based on LiODFB (0.9mol / L 1LiODFB-SLS) is expected to be a new electrolyte system of 5V high voltage lithium ion battery. When it is applied to MCMB, the oxidation decomposition potential of DMSs (dimethyl sulfite) is higher than 5.5V, which is expected to be a new type of electrolyte system for 5V high voltage lithium ion battery. In the mesophase carbon microsphere / Li 路LiFeP04 / Li battery, the electrolyte system of 0.9mol L-1 LiODFB-SL-DMS formed stable on the surface of the electrode material. The effective interface film can improve the cycle performance and rate performance of the battery. As an extension of the above results, the oxalic acid radical group in LiODFB was further replaced by sulfur-containing groups in the experiment. LiBF3SO4H _ 2SO _ 4 was prepared for the first time and its basic physical properties were studied. The electrochemical properties of LiBF2SO4 based electrolytes were systematically studied by using LiPF.base electrolyte system as reference material. Due to the effect of LiBF2SO4 on the electrode / electrolyte interfacial membrane, the experimental cells assembled with 1.0 mol L -1 LiBF2SO4-EC (dimethyl carbonate / 1: 1, volume ratio) electrolyte system have good electrochemical stability. Especially at 80 鈩

本文編號：1572581