Rennie Anthony J R, Sanchez-Ramirez Nédher, Torresi Roberto M, Hall Peter J
Department of Chemical & Biological Engineering, University of Sheffield , Sheffield S1 3JD, United Kingdom.
Instituto de Química, Universidade de São Paulo , CP 26077, 05513-970 São Paulo, Brazil.
J Phys Chem Lett. 2013 Sep 5;4(17):2970-2974. doi: 10.1021/jz4016553. Epub 2013 Aug 19.
Electrochemical capacitors (ECs) are electrical energy storage devices that have the potential to be very useful in a wide range of applications, especially where there is a large disparity between peak and average power demands. The use of ionic liquids (ILs) as electrolytes in ECs can increase the energy density of devices; however, the viscosity and conductivity of ILs adversely influence the power density of the device. We present experimental results where several ILs containing different cations have been employed as the electrolyte in cells containing mesoporous carbon electrodes. Specifically, the behavior of ILs containing an ether bond in an alkyl side chain are compared with those of a similar structure and size but containing purely alkyl side chains. Using electrochemical impedance spectroscopy and constant current cycling, we show that the presence of the ether bond can dramatically increase the specific capacitance and reduce device resistance. These results have the important implication that such ILs can be used to tailor the physical properties and electrochemical performance of IL-based electrolytes.
电化学电容器（ECs）是电能存储设备，在广泛的应用中具有潜在的巨大用途，特别是在峰值功率需求与平均功率需求存在较大差距的情况下。在电化学电容器中使用离子液体（ILs）作为电解质可以提高设备的能量密度；然而，离子液体的粘度和电导率会对设备的功率密度产生不利影响。我们展示了实验结果，其中几种含有不同阳离子的离子液体被用作含有介孔碳电极的电池中的电解质。具体而言，将在烷基侧链中含有醚键的离子液体的行为与结构和尺寸相似但仅含有烷基侧链的离子液体的行为进行了比较。通过电化学阻抗谱和恒流循环，我们表明醚键的存在可以显著提高比电容并降低设备电阻。这些结果具有重要意义，即此类离子液体可用于调整基于离子液体的电解质的物理性质和电化学性能。
