Weber Isabella, Kim Jihyun, Buchner Florian, Schnaidt Johannes, Behm R Jürgen
Helmholtz-Institute Ulm (HIU) Electrochemical Energy Storage, Helmholtzstraße 11, 89081, Ulm, Germany.
Institute of Surface Chemistry and Catalysis, Ulm University, Albert-Einstein-Allee 47, 89081, Ulm, Germany.
ChemSusChem. 2020 May 22;13(10):2589-2601. doi: 10.1002/cssc.202000495. Epub 2020 Apr 24.
The process of solid-electrolyte interphase (SEI) formation is systematically investigated along with its chemical composition on carbon electrodes in an ionic liquid-based, Li-containing electrolyte in a combined surface science and electrochemical model study using highly oriented pyrolytic graphite (HOPG) and binder-free graphite powder electrodes (Mage) as model systems. The chemical decomposition process is explored by deposition of Li on a pre-deposited multilayer film of 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ([BMP][TFSI]) under ultrahigh vacuum conditions. Electrochemical SEI formation is induced by and monitored during potential cycling in [BMP][TFSI]+0.1 m LiTFSI. The chemical composition of the resulting layers is characterized by X-ray photoelectron spectroscopy (XPS), both at the surface and in deeper layers, closer to the electrode|SEI interface, after partial removal of the film by Ar ion sputtering. Clear differences between chemical and electrochemical SEI formation, and also between SEI formation on HOPG and Mage electrodes, are observed and discussed.
在一项结合表面科学和电化学的模型研究中，以高度取向热解石墨（HOPG）和无粘结剂石墨粉末电极（Mage）为模型体系，在基于离子液体的含锂电解质中，系统地研究了碳电极上固体电解质界面（SEI）的形成过程及其化学成分。在超高真空条件下，通过将锂沉积在预先沉积的1-丁基-1-甲基吡咯烷鎓双（三氟甲基磺酰）亚胺（[BMP][TFSI]）多层膜上，探索化学分解过程。在[BMP][TFSI]+0.1 m LiTFSI中进行电位循环时，诱导并监测电化学SEI的形成。通过X射线光电子能谱（XPS）对所得层的化学成分进行表征，在通过氩离子溅射部分去除薄膜后，分别在表面和更靠近电极|SEI界面的较深层进行表征。观察并讨论了化学和电化学SEI形成之间以及HOPG和Mage电极上SEI形成之间的明显差异。
