Density Functional Study of the Electric Double Layer Formed by a High Density Electrolyte

作者：Henderson Douglas^*; Lamperski Stanislaw; Jin Zhehui; Wu Jianzhong

来源：Journal of Physical Chemistry B, 2011, 115(44): 12911-12914.

DOI：10.1021/jp2078105

We use a classical density functional theory (DFT) to study the electric double layer formed by charged hard spheres near a planar charged surface. The DFT predictions are found to be in good agreement with recent computer simulation results. We study the capacitance of the charged hard-sphere system at a range of densities and surface charges and find that the capacitance exhibits a local minimum at low ionic densities and small electrode charge. Although this charging behavior is typical for an aqueous electrolyte solution, the local minimum gradually turns into a maximum as the density of the hard spheres increases. Charged hard spheres at high density provide a reasonable first approximation far ionic liquids. In agreement with experiment, the capacitance of this model ionic liquid double layer has a maximum at small electrode charge density.

• 出版日期2011-11-10