离子液体-锂盐混合体系的电化学界面微分电容测定

Electrochemical Differential Capacity of the Mixture of[Bmim][OTf]Ionic Liquid and Lithium Ion on Gold Electrode

采用电化学交流阻抗法研究了离子液体1-丁基-3-甲基咪唑三氟甲磺酸([Bmim][OTf]:1-butyl-3-methylimidazolium trifluoromethane-sulfonate)-氯化锂(LiCl)混合体系在多晶金电极表面的电化学双电层微分电容.根据所得到的近似钟形的曲线对体系的零电荷电势进行了分析.同时实验结果表明所得到的电容电势曲线受到电势改变方向的影响,出现明显的延迟效应.对延迟效应的机理进行了分析.同时,对温度对微分电容曲线的影响也进行了研究,发现微分电容值会随着温度升高而增大.

Differential capacity and cyclic voltammetric measurements have been carried out for gold electrode in mixture of 1-butyl-3-methylimidazolium trifluoromethanesulfonate ionic liquid and iithium chloride. The potential of zero charge has been predicted from the bell-shaped differential capacity curve obtained. Capacity around potential of zero charge increases with increasing temperature. Significant hysteresis has been observed from the capacity-potential curves by different potential scanning direction. The hysteresis effect is due to both the surface binding energy of ions on Au surface and Madelung energy among ions.