新型导电盐（三氟甲基磺酰）（三氟乙氧基磺酰）亚胺锂及其非水电解液的制备与性能

摘要

制备了一种新型含氟磺酰亚胺锂盐(三氟甲基磺酰)(三氟乙氧基磺酰)亚胺锂{Li[( CF3 SO2)·(CF3CH2OSO2)N], Li[TFO-TFSI]}及其与碳酸乙烯酯(EC)/碳酸甲乙酯(EMC)混合溶剂(3：7,体积比)组成的非水电解液.采用核磁共振波谱( NMR)、红外光谱( IR)、质谱( MS)、元素分析( EA)和离子色谱( IC)等手段对合成锂盐Li[ TFO-TFSI]进行了结构表征及纯度分析.通过差示量热扫描( DSC)和热重分析( TG)对Li[TFO-TFSI]及其电解液1.0 mol/L Li[TFO-TFSI]-EC/EMC(3：7)的热学性质进行了表征.采用交流阻抗( EIS)、循环伏安( CV)、计时安培法及扫描电子显微镜( SEM)等对Li[ TFO-TFSI]/碳酸酯电解液的基础物化和电化学性质进行了表征.结果表明, Li[ TFO-TFSI]/碳酸酯电解液具有较好的电化学稳定性；在4.2 V( vs. Li/Li+)以下Al箔不发生腐蚀；室温下基于Li[ TFO-TFSI]/碳酸酯电解液的Li/人造石墨和人造石墨/LiCoO2电池均保持较好的循环性能,特别是人造石墨/LiCoO2锂离子电池循环100周后,其比容量保持率明显高于相应的基于LiPF6/碳酸酯电解液体系的电池.%A novel lithium salt, lithium( trifluoromethanesulfonyl) ( trifluoroethoxysulfonyl) imide{Li[ ( CF3 SO2 ) ( CF3 CH2 OSO2 ) N] , Li[ TFO-TFSI]}, and the corresponding nonaqueous electrolytes of 1.0 mol/L Li[TFO-TFSI] in a mixture of ethylene carbonate/ethyl methyl carbonate(EC/EMC, 3:7, volume ra-tio) were prepared. The structure, composition and purity of the as-prepared Li[ TFO-TFSI] were confirmed by nuclear magnetic resonance spectroscopy ( NMR ) , infrared spectroscopy ( IR ) , mass spectrometry ( MS ) , elemental analysis( EA) , and ion chromatography( IC) . The thermal properties of Li[ TFO-TFSI] and its non-aqueous electrolytes, 1.0 mol/L Li[TFO-TFSI]-EC/EMC(3:7), were characterized by differential scanning calorimetry( DSC) and thermogravimetric analysis( TGA) . The fundamental properties of nonaqueous electro-lyte solution of Li [ TFO-TFSI ] were characterized by electrochemical impedance spectroscopy ( EIS ) , cyclic voltammetry( CV) , chronoamperometry and scanning electron microscope( SEM) . The nonaqueous electrolytes of Li[ TFO-TFSI] shows excellent electrochemical stability, and does not corrode Al below 4.2 V. Both Li/synthetic graphite and synthetic graphite/LiCoO2 cells using Li[ TFO-TFSI] show good cycling performances at room temperature, and the graphite/LiCoO2 cells using Li[ TFO-TFSI] shows much better capacity retention after 100 cycles than those using LiPF6 .