通过分离界面效应与真实限域效应预测石墨烯纳米限域中的电解质密度、扩散系数和电导率
Electrolyte density, diffusivity and conductivity in graphene nanoconfinement predicted by separating interfacial from genuine confinement effects
- Freie Universität Berlin（柏林自由大学）
- École Polytechnique Fédérale de Lausanne（洛桑联邦理工学院）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本文提出界面亏损长度框架，将受限电解质的密度、扩散系数和电导率分解为界面与限域贡献，发现真实限域效应仅出现在狭缝高度小于1纳米时，并能预测不同高度和浓度下的性质。
AI中文摘要：
受限水电解质表现出与体相行为的强烈偏差，但目前尚不清楚哪些变化源于真正的限域诱导改性，哪些仅仅反映了界面的影响。在此，我们引入了一个界面亏损长度框架，能够将受限电解质溶液的密度、扩散系数和电导率分解为界面贡献和限域贡献。通过将该框架应用于与体相储层耦合的平面石墨烯纳米狭缝中不同电解质浓度的碱金属卤化物水溶液的分子动力学模拟，我们表明真正的限域效应仅在狭缝高度 $H \lesssim 1$ nm 时出现；对于较大的 H，与体相行为的偏差可由界面亏损长度定量捕获。这些亏损长度具有强烈的离子特异性，并且对于水和盐的密度以及电导率通常为正，这意味着石墨烯界面降低了这些可观测量的值，而扩散系数的亏损长度往往为负，对应于相对于相应体相参考值更大的狭缝自扩散系数。我们的亏损长度框架适用于来自纳米受限电解质实验或模拟的任何可观测量，并可预测不同狭缝高度 H 和储层电解质浓度下的受限电解质性质。
英文摘要：
Confined aqueous electrolytes exhibit strong deviations from bulk behaviour, but it remains unclear which changes arise from genuine confinement-induced modification and which merely reflect the influence of interfaces. Here, we introduce an interfacial deficit-length framework, capable of decomposing density, diffusivity, and conductivity of confined electrolyte solutions into interfacial and confinement contributions. By applying the framework to molecular dynamics simulations of aqueous alkali halides in planar graphene nanoslits coupled to bulk reservoirs at variable electrolyte concentration, we show that genuine confinement effects emerge only for slit heights $H \lesssim 1$ nm; for larger H, deviations from bulk behaviour are quantitatively captured by interfacial deficit lengths. These deficit lengths are strongly ion-specific and generally positive for water and salt densities as well as for conductivities, meaning that graphene interfaces reduce the values of these observables, while diffusivity deficit lengths tend to be negative, corresponding to larger slit self-diffusivities relative to the corresponding bulk reference. Our deficit-length framework is applicable to any observable from experiments or simulations on nanoconfined electrolytes and predicts confined electrolyte properties for variable slit height H and reservoir electrolyte concentrations.
