高等学校化学学报 ›› 2012, Vol. 33 ›› Issue (04): 786.doi: 10.3969/j.issn.0251-0790.2012.04.025

• 物理化学 • 上一篇    下一篇

新型锂盐Li[CF3BF3]电解液的制备与性能

韩鸿波, 郭俊, 冯绍伟, 聂进, 周志彬   

  1. 华中科技大学化学与化工学院, 武汉 430074
  • 收稿日期:2011-09-05 出版日期:2012-04-10 发布日期:2012-04-10
  • 作者简介:聂进, 男, 博士, 教授, 博士生导师, 主要从事有机氟化学和含氟有机功能材料研究. E-mail: niejin@mail.hust.edu.cn'周志彬, 男, 博士, 教授, 博士生导师, 主要从事有机氟化学和非水电解质材料研究. E-mail: zb-zhou@mail.hust.edu.cn
  • 基金资助:

    国家自然科学基金(批准号: 50873041)资助.

Preparation and Properties of Electrolyte Li[CF3BF3] as a Novel Conductive Salt

HAN Hong-Bo, GUO Jun, FENG Shao-Wei, NIE Jin, ZHOU Zhi-Bin   

  1. School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
  • Received:2011-09-05 Online:2012-04-10 Published:2012-04-10
  • Supported by:

    国家自然科学基金(批准号: 50873041)资助.

摘要: 制备了1种高纯度的新型锂盐三氟甲基三氟硼酸锂(Li[CF3BF3]), 通过核磁共振(NMR)、元素分析(EA)及离子色谱(IC)对其结构进行表征和杂质分析. 采取示差扫描量热(DSC)、交流阻抗(EIS)、循环伏安(CV)和扫描电镜(SEM)等方法研究了1 mol/L Li[CF3BF3]-EC/EMC/DMC(体积比5: 3: 2)电解液的物化和电化学性质. 结果表明, Li[CF3BF3]基电解液的电导率和Li+迁移数远高于LiBF4, 氧化电位高达5.91 V(vs. Li+/Li), 在镍电极表面能观察到可逆的锂沉积-溶出过程, 并对Al箔表现出优良的钝化性能. 研究了Li[CF3BF3]基电解液的电导率与温度和浓度、黏度与浓度的变化规律, 以及一系列浓度电解液的相变规律. Li/C半电池测试结果表明, —CF3取代LiBF4的1个F原子后, 其衍生产物Li[CF3BF3]明显改善了电解液与人造石墨的相容性.

关键词: 锂离子电池电解液, 三氟甲基三氟硼酸锂, 迁移数

Abstract: A novel lithium salt, Li[CF3BF3], was prepared and structure-elucidated by 1H NMR and elemental analysis. The impurities contents in Li[CF3BF3] were determined by ion chromatography. The physicochemical and electrochemical properties of 1 mol/L Li[CF3BF3] in ethylene carbonate/ethyl methyl car-bonate/dimethyl carbonate(EC/EMC/DMC)(volume ratio 5: 3: 2) were extensively investigated by differential scanning calorimetry(DSC), electrochemical impedance spectroscopy(EIS), cyclic voltammogram(CV) and scanning electron microscope(SEM). The results indicate that the Li[CF3BF3]-containing electrolyte is much more conductive than that of LiBF4 and show an anodic stability up to 5.91 V(vs. Li+/Li) and highly reversible deposition-dissolution process on the Ni electrode, and is passivated effectively toward the Al anodic collector. The correlations between conductivities and temperatures or Li[CF3BF3] concentrations and between viscosities of the electrolytes and Li[CF3BF3] concentrations were also studied, respectively. Moreover, charge/discharge test of Li/graphite half-cells suggests that the Li[CF3BF3] based electrolyte was compatible well with graphite electrode.

Key words: Electrolyte of Li+ cell, Li[CF3BF3], Transference number

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