【摘要】 研究了以一种咪唑类离子液体1-乙基-3-甲基咪唑四氟硼酸盐(EMI.BF4)为支持电解质盐,分别以碳酸丙烯酯(PC)、乙腈(AN)、二甲基甲酰胺(DMF)为溶剂的3种新型电解液的电化学特性;进而使用这3种新型电解液组装了活性碳电极双电层电容器(EDLC),对电容器的性能进行了研究。结果表明:EMI.BF4在PC、AN、DMF中均具有较大的溶解度(>6mol/L);25℃时EMI.BF4/PC、EMI.BF4/AN和EMI.BF4/DMF溶液浓度分别为2.7mol/L、2.4mol/L和2.6mol/L时电导率达最大值(20.3mS/cm、66.3mS/cm和35.3mS/cm),对应的电化学窗口分别为3.7V、4.0V和3.6V。以这3种EMI.BF4/有机溶剂溶液为电解液的双电层电容器,在充电后期均未出现因“离子贫乏效应”所导致的电容器电压急剧升高现象;其中以2.4mol/LEMI.BF4/AN为电解液的电容器具有最为优良的充放电性能和相对较高的工作电压。更多还原

【Abstract】 The electrochemical properties of three new kinds of liquid electrolyte s, 1-ethyl-3-methyl imidazolium tetrafluoroborate(EMI.BF4), a kind of imidazoliu m ionic liquid as electrolyte salt, and the organic solvents propylene carbonate (PC) , acetonitrile(AN) and dimethylformamide(DMF) respectively as solvent were investigated. The electric double-layer capacitors, based on activated carbon p owders and these new types of electrolytes as electrolytes, were prepared and te sted. The result shows that the solubility of the EMI.BF4 in these organic solve nts are high (>6 mol / L), the highest conductivity of 66.3 mS /cm is observed f or 2.4 mol / L EMI.BF4 / AN at 25 ℃, the value of EMI.BF4 / PC is 20.3 mS /cm a t 2.7 mol / L and EMI.BF4 / DMF is 35.3 mS / cm at 2.6 mol / L. The stable poten tial window is about 4.0 V for 2.4 mol / L EMI.BF4 / AN, 3.7 V for 2.7 mol / L E MI.BF4 / PC, 3.6 V for 2.6 mol / L EMI.BF4 / DMF. All of the EDLCs have no pheno mena of voltage increase rapidly result from "ionic absent effect" at the charge later. The capacitor using 2.4 mol / L EMI.BF4 / AN as electrolyte shows the mo st excellent charge and discharge performance and high work voltage among of the m.更多还原