Zhen Erfei, Chen Yanxia, Huang Jun
Hefei National Research Center for Physical Sciences at Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China.
Institute of Energy Technologies, IET-3: Theory and Computation of Energy Materials, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.
J Chem Phys. 2025 Apr 14;162(14). doi: 10.1063/5.0251548.
Differential capacitance (Cdl) is arguably the most important lumped parameter of electrical double layers (EDLs). Two peaks in the Cdl profile have been commonly attributed to the crowding of counterions within the EDL. More recent studies have suggested that the two peaks are primarily caused by orientational polarization of interfacial water molecules. Herein, this recent perspective is extended by considering orientation-dependent adsorption free energy of water and tested at Au(111)-aqueous solution interfaces. Our comparative analysis of the ion dependency of the Cdl profile corroborates the view that the capacitance peaks are caused mainly by the saturation of the orientational polarization of interfacial water molecules. In addition, the temperature dependency of the Cdl profile is consistently interpreted as a consequence of the temperature effects on the orientational polarization of interfacial water.
微分电容（Cdl）可以说是双电层（EDL）最重要的集总参数。Cdl曲线中的两个峰值通常归因于双电层中反离子的聚集。最近的研究表明，这两个峰值主要是由界面水分子的取向极化引起的。在此，通过考虑水的取向依赖性吸附自由能扩展了这一最新观点，并在金（111）-水溶液界面进行了测试。我们对Cdl曲线离子依赖性的比较分析证实了以下观点：电容峰值主要是由界面水分子取向极化的饱和引起的。此外，Cdl曲线的温度依赖性始终被解释为温度对界面水取向极化影响的结果。
