标题： 离子关联与水合在盐中水电解质的双电层中的作用 显示英文标题

标题： Ionic Associations and Hydration in the Electrical Double Layer of Water-in-Salt Electrolytes

摘要： 水-盐电解质（WiSEs）是一类有前途的高浓度电解质，因其扩展的电化学稳定性窗口、良好的导电性和阳离子迁移数以及灭火特性，被应用于能量存储设备中。 这些独特的性质被认为源于阴离子主导的离子网络和用于阳离子传输的相互渗透的水通道，这表明WiSE中的关联对于理解其性质至关重要。 目前，关联主要在体相中进行了研究，而对带电界面附近的电解质结构关注较少。 在这里，我们开发了一种WiSE电双层（EDL）的理论，在该理论中，我们一致考虑了物种向凯莱树聚集体的热可逆关联。 该理论预测了EDL的不对称结构。 在负电压下，水合Li$^+$占主导地位，并且在较大电压下首先略微增强聚集，然后分解。 与体相相比，在正电压下，团簇严格减少。 进行WiSE的EDL原子分子动力学（MD）模拟提供了用于验证的EDL数据和用于理论参数化的体相数据。 将理论预测与MD进行验证显示出良好的定性一致性。 此外，我们进行了电化学阻抗测量以确定所研究的LiTFSI WiSE的微分电容，并且也发现与我们的理论有合理的吻合。 总体而言，所开发的方法可以用来研究EDL中的离子聚集和溶剂化效应，这些效应可以用于理解固态电解质界面形成的前提条件。 显示英文摘要

摘要： Water-in-Salt-Electrolytes (WiSEs) are an exciting class of concentrated electrolytes finding applications in energy storage devices because of their expanded electrochemical stability window, good conductivity and cation transference number, and fire-extinguishing properties. These distinct properties are thought to originate from the presence of an anion-dominated ionic network and interpenetrating water channels for cation transport, which indicates that associations in WiSEs are crucial to understanding their properties. Currently, associations have mainly been investigated in the bulk, while little attention has been given to the electrolyte structure near electrified interfaces. Here, we develop a theory for the electrical double layer (EDL) of WiSEs, where we consistently account for the thermoreversible associations of species into Cayley tree aggregates. The theory predicts an asymmetric structure of the EDL. At negative voltages, hydrated Li$^+$ dominate and cluster aggregation is initially slightly enhanced before disintegration at larger voltages. At positive voltages when compared to the bulk, clusters are strictly diminished. Performing atomistic molecular dynamics (MD) simulations of the EDL of WiSE provides EDL data for validation and bulk data for parameterization of our theory. Validating the predictions of our theory against MD showed good qualitative agreement. Furthermore, we performed electrochemical impendence measurements to determine the differential capacitance of the studied LiTFSI WiSE and also found reasonable agreement with our theory. Overall, the developed approach can be used to investigate ionic aggregation and solvation effects in the EDL, which amongst other properties, can be used to understand the pre-cursers for solid-electrolyte interphase formation.