Abstract A method for performing X-ray absorption spectroscopy (XAS) in the soft X-ray region was developed to investigate the surface-sensitive electron signal of electrode/electrolyte interfaces in common multivalent based organic solvents under in situ/operando conditions. Our approach enables us to probe the molecular-scale structure of electrode interfaces by measuring total electron yield and is suitable for redox systems exhibiting low intrinsic electrochemical current. In-situ F K-edge XAS measurements in a 0.5 M Magnesium bis(trifluoromethanesulfonimide)/2-Methyltetrahydrofuran (Mg(TFSI)2/2-MeTHF) electrolyte were carried out to determine the evolution of interfacial species during the electrochemical charging/discharging process. Time-dependent density-functional theory (TD-DFT) simulation indicate that the F K-edge evolution is the result of interfacial chemical environment change driven by electrochemical potential. In addition, we performed the “operando XAS” which runs the CV and collects spectra simultaneously. By using this method, the non-equilibrium state of condensed matter interfaces and interfacial dynamical transient process can be revealed.

中文翻译：

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分子尺度上电极/电解质界面的原位/操作X射线吸收光谱研究

摘要 开发了一种在软 X 射线区域进行 X 射线吸收光谱 (XAS) 的方法，以在原位/操作条件下研究常见多价有机溶剂中电极/电解质界面的表面敏感电子信号。我们的方法使我们能够通过测量总电子产率来探测电极界面的分子级结构，并且适用于表现出低本征电化学电流的氧化还原系统。在 0.5 M 镁双（三氟甲磺酰亚胺）/2-甲基四氢呋喃（Mg（TFSI）2/2-MeTHF）电解质中进行原位 F K-edge XAS 测量，以确定电化学充电/放电过程中界面物质的演变过程。瞬态密度泛函理论 (TD-DFT) 模拟表明 F K 边缘演化是电化学势驱动的界面化学环境变化的结果。此外，我们还执行了“operando XAS”，它运行 CV 并同时收集光谱。利用该方法可以揭示凝聚态界面的非平衡状态和界面动力学瞬态过程。