Holoubek John, Baskin Artem, Lawson John W, Khemchandani Hridayanand, Pascal Tod A, Liu Ping, Chen Zheng
Department of NanoEngineering, University of California, San Diego, La Jolla, California 92093, United States.
NASA Ames Research Center, Moffett Field, California 94035, United States.
J Phys Chem Lett. 2022 May 26;13(20):4426-4433. doi: 10.1021/acs.jpclett.2c00770. Epub 2022 May 13.
To better understand the influence of electrolyte chemistry on the ion-desolvation portion of charge-transfer beyond the commonly applied techniques, we apply free-energy sampling to simulations involving diethyl ether (DEE) and 1,3-dioxoloane/1,2-dimethoxyethane (DOL/DME) electrolytes, which display bulk solvation structures dominated by ion-pairing and solvent coordination, respectively. This analysis was conducted at a pristine electrode with and without applied bias at 298 and 213 K to provide insights into the low-temperature charge-transfer behavior, where it has been proposed that desolvation dominates performance. We find that, to reach the inner Helmholtz layer, ion-paired structures are advantageous and that the Li ion must reach a total coordination number of 3, which requires the shedding of 1 species in the DEE electrolyte or 2-3 species in DOL/DME. This work represents an effort to predict the distinct thermodynamic states as well as the most probable kinetic pathways of ion desolvation relevant for the charge transfer at electrochemical interphases.
为了在超越常用技术的情况下更好地理解电解质化学对电荷转移的离子去溶剂化部分的影响，我们将自由能采样应用于涉及二乙醚（DEE）和1,3 - 二氧戊环/1,2 - 二甲氧基乙烷（DOL/DME）电解质的模拟中，这两种电解质分别呈现出以离子对和溶剂配位为主导的本体溶剂化结构。该分析在298 K和213 K下对有无外加偏压的原始电极进行，以深入了解低温电荷转移行为，在此行为中有人提出去溶剂化主导性能。我们发现，为了到达内亥姆霍兹层，离子对结构是有利的，并且锂离子必须达到总配位数为3，这需要在DEE电解质中脱去1种物质或在DOL/DME中脱去2 - 3种物质。这项工作致力于预测与电化学界面处电荷转移相关的离子去溶剂化的不同热力学状态以及最可能的动力学途径。
