Olschewski Mark, Gustus René, Marschewski Marcel, Höfft Oliver, Endres Frank
Institute of Electrochemistry, Clausthal University of Technology, Arnold-Sommerfeld-Str 6, D-38678 Clausthal-Zellerfeld, Germany.
Phys Chem Chem Phys. 2014 Dec 21;16(47):25969-77. doi: 10.1039/c4cp03091e. Epub 2014 Oct 30.
In this experimental investigation the interaction of lithium with 1-octyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide ([OMIm]Tf2N) is shown. For this purpose thin films of lithium and [OMIm]Tf2N were successively vapor deposited on a copper substrate and analyzed by X-ray Photoelectron Spectroscopy (XPS) as well as by Ultraviolet Photoelectron Spectroscopy (UPS). When [OMIm]Tf2N is evaporated on top of a thin lithium film a chemical shift analysis of XPS spectra shows a variety of reaction products like LiF, Li2O and LixCHy which reveals the instability of the IL against lithium. Time resolved XPS spectra were discussed to distinguish cation reactions from beam damage effects. In a second step lithium is deposited on a [OMIm]Tf2N layer. The XPS spectra are in agreement with the results of the previous step, but show some differences concerning the [OMIm] cation. In a third step [OMIm]Tf2N has been deposited on a passivated lithium layer. XPS results show nearly unaffected Tf2N anions and partially decomposed OMIm cations. Interestingly the cation reactions show similarities when compared to the interaction of [C4C1Pyrr]Tf2N (1-butyl-1-methylpyrrolidinium bis[trifluoromethylsulfonyl]amide) and lithium.
在本实验研究中，展示了锂与1-辛基-3-甲基咪唑双（三氟甲基磺酰）亚胺（[OMIm]Tf₂N）的相互作用。为此，将锂和[OMIm]Tf₂N的薄膜依次气相沉积在铜衬底上，并通过X射线光电子能谱（XPS）以及紫外光电子能谱（UPS）进行分析。当[OMIm]Tf₂N蒸发在锂薄膜之上时，XPS光谱的化学位移分析显示出多种反应产物，如LiF、Li₂O和LixCHy，这揭示了离子液体对锂的不稳定性。讨论了时间分辨XPS光谱以区分阳离子反应和束损伤效应。在第二步中，将锂沉积在[OMIm]Tf₂N层上。XPS光谱与上一步结果一致，但在[OMIm]阳离子方面显示出一些差异。在第三步中，将[OMIm]Tf₂N沉积在钝化的锂层上。XPS结果显示[Tf₂N]⁻阴离子几乎未受影响，而[OMIm]⁺阳离子部分分解。有趣的是，与[C₄C₁Pyrr]Tf₂N（1-丁基-1-甲基吡咯烷双[三氟甲基磺酰]亚胺）与锂的相互作用相比，阳离子反应表现出相似性。
