新型锂盐Li[CF_3BF_3]电解液的制备与性能  

Preparation and Properties of Electrolyte Li[CF_3BF_3] as a Novel Conductive Salt

作　　者：韩鸿波[1] 郭俊[1] 冯绍伟[1] 聂进[1] 周志彬[1] 

机构地区：[1]华中科技大学化学与化工学院,武汉430074

出　　处：《高等学校化学学报》2012年第4期786-793,共8页Chemical Journal of Chinese Universities

基　　金：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.A novel lithium salt,Li,was prepared and structure-elucidated by 1H NMR and elemental analysis.The impurities contents in Li were determined by ion chromatography.The physicochemical and electrochemical properties of 1 mol/L Li 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-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 concentrations and between viscosities of the electrolytes and Li concentrations were also studied,respectively.Moreover,charge/discharge test of Li/graphite half-cells suggests that the Li based electrolyte was compatible well with graphite electrode.

关 键 词：锂离子电池电解液 三氟甲基三氟硼酸锂 迁移数 

分 类 号：O646[理学—物理化学]