Wang Zhenxing, Olmsted David L, Asta Mark, Laird Brian B
Department of Chemistry, University of Kansas, Lawrence, KS 66045, USA.
J Phys Condens Matter. 2016 Nov 23;28(46):464006. doi: 10.1088/0953-8984/28/46/464006. Epub 2016 Sep 14.
For the molecular simulation of electric double layer capacitors (EDLCs), a number of methods have been proposed and implemented to determine the one-dimensional electric potential profile between the two electrodes at a fixed potential difference. In this work, we compare several of these methods for a model LiClO4-acetonitrile/graphite EDLC simulated using both the traditional fixed-charged method (FCM), in which a fixed charge is assigned a priori to the electrode atoms, or the recently developed constant potential method (CPM) (2007 J. Chem. Phys. 126 084704), where the electrode charges are allowed to fluctuate to keep the potential fixed. Based on an analysis of the full three-dimensional electric potential field, we suggest a method for determining the averaged one-dimensional electric potential profile that can be applied to both the FCM and CPM simulations. Compared to traditional methods based on numerically solving the one-dimensional Poisson's equation, this method yields better accuracy and no supplemental assumptions.
对于双电层电容器（EDLCs）的分子模拟，已经提出并实施了多种方法来确定在固定电势差下两个电极之间的一维电势分布。在这项工作中，我们比较了其中几种方法，这些方法用于模拟一个LiClO₄ - 乙腈/石墨EDLC模型，采用了传统的固定电荷方法（FCM），即在电极原子上预先分配固定电荷，或者采用最近开发的恒电势方法（CPM）（《化学物理杂志》2007年第126卷，084704），在该方法中允许电极电荷波动以保持电势固定。基于对完整三维电势场的分析，我们提出了一种确定平均一维电势分布的方法，该方法可应用于FCM和CPM模拟。与基于数值求解一维泊松方程的传统方法相比，该方法具有更高的精度且无需补充假设。
