Scalfi Laura, Dufils Thomas, Reeves Kyle G, Rotenberg Benjamin, Salanne Mathieu
Sorbonne Université, CNRS, Physico-chimie des Électrolytes et Nanosystèmes Interfaciaux, PHENIX, F-75005 Paris, France.
J Chem Phys. 2020 Nov 7;153(17):174704. doi: 10.1063/5.0028232.
Spurred by the increasing needs in electrochemical energy storage devices, the electrode/electrolyte interface has received a lot of interest in recent years. Molecular dynamics simulations play a prominent role in this field since they provide a microscopic picture of the mechanisms involved. The current state-of-the-art consists of treating the electrode as a perfect conductor, precluding the possibility to analyze the effect of its metallicity on the interfacial properties. Here, we show that the Thomas-Fermi model provides a very convenient framework to account for the screening of the electric field at the interface and differentiating good metals such as gold from imperfect conductors such as graphite. All the interfacial properties are modified by screening within the metal: the capacitance decreases significantly and both the structure and dynamics of the adsorbed electrolyte are affected. The proposed model opens the door for quantitative predictions of the capacitive properties of materials for energy storage.
受电化学储能装置日益增长的需求推动，电极/电解质界面近年来受到了广泛关注。分子动力学模拟在该领域发挥着重要作用，因为它们提供了所涉及机制的微观图景。当前的技术水平是将电极视为理想导体，这排除了分析其金属性对界面性质影响的可能性。在此，我们表明托马斯 - 费米模型提供了一个非常方便的框架，用于解释界面处电场的屏蔽，并区分诸如金等良金属与诸如石墨等非理想导体。金属内部的屏蔽会改变所有的界面性质：电容显著降低，吸附电解质的结构和动力学都会受到影响。所提出的模型为储能材料电容性质的定量预测打开了大门。
