Ye Benjamin Bobin, Wang Zhen-Gang
Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California, 91125, USA.
Phys Chem Chem Phys. 2022 May 18;24(19):11573-11584. doi: 10.1039/d2cp00166g.
Recent mean-field theories predict that room-temperature ionic liquid (RTIL) electric double-layer capacitors (EDLCs) undergo a spontaneous surface charge separation (SSCS) with no applied potential. In this study, we construct a coarse-grained molecular model that corresponds to the mean-field models to directly simulate the behavior of RTILs without invoking mean-field approximations. In addition to observing the SSCS transition, we highlight the importance of the image charge interactions and explore the enhanced in-plane ordering on the electrodes, two effects not accounted for by the mean-field theories. By calculating and comparing the differential capacitance for RTILs confined between perfectly conducting and non-metal electrodes, we show that the image charge interactions drastically improve the energy storage properties of RTIL EDLCs.
最近的平均场理论预测，室温离子液体（RTIL）双电层电容器（EDLC）在没有施加电势的情况下会发生自发表面电荷分离（SSCS）。在本研究中，我们构建了一个与平均场模型相对应的粗粒度分子模型，以直接模拟RTIL的行为，而无需调用平均场近似。除了观察SSCS转变外，我们还强调了镜像电荷相互作用的重要性，并探索了电极上增强的面内有序性，这是平均场理论未考虑的两种效应。通过计算和比较限制在理想导电电极和非金属电极之间的RTIL的微分电容，我们表明镜像电荷相互作用极大地改善了RTIL EDLC的储能特性。
