Water molecules mute the dependence of the double-layer potential profile on ionic strength
Water molecules mute the dependence of the double-layer potential profile on ionic strength
复制标题
水分子减弱了双层电位分布对离子强度的依赖性
DOI：
10.1039/d3fd00114h
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发表时间：
2023
影响因子：
3.4
通讯作者：
Willard, Adam
中科院分区：
文献类型：
--
作者：
Limaye, Aditya;Suvlu, Dylan;Willard, Adam
我们提出的纳米电化学电池的分子动力学模拟的结果。模拟包括具有不同离子强度的电解质水溶液（即，浓度范围为0-4 M）。我们通过计算双电层区域的静电势分布来分析这些模拟，发现它几乎与离子浓度无关，与标准连续理论的预测形成鲜明对比。我们将这种缺乏浓度依赖性归因于水分子在电极-溶液界面处的分子影响。这些影响包括水的介电响应的分子表现，其倾向于淹没离子的相对较弱的屏蔽要求。为了支持我们的分析，我们将水的界面响应分解为三个主要贡献：分子分层，内在（零场）取向极化和偶极介电响应。
We present the results of molecular dynamics simulations of a nanoscale electrochemical cell. The simulations include an aqueous electrolyte solution with varying ionic strength (i.e., concentrations ranging from 0–4 M) between a pair of metallic electrodes held at constant potential difference. We analyze these simulations by computing the electrostatic potential profile of the electric double-layer region and find it to be nearly independent of ionic concentration, in stark contrast to the predictions of standard continuum-based theories. We attribute this lack of concentration dependence to the molecular influences of water molecules at the electrode–solution interface. These influences include the molecular manifestation of water’s dielectric response, which tends to drown out the comparatively weak screening requirement of the ions. To support our analysis, we decompose water’s interfacial response into three primary contributions: molecular layering, intrinsic (zero-field) orientational polarization, and the dipolar dielectric response.