In-Situ Raman Investigation of Polysulfide Formation in Li-S Cells
In-Situ Raman Investigation of Polysulfide Formation in Li-S Cells
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DOI：
10.1149/2.045308jes
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发表时间：
2013-01-01
影响因子：
3.9
通讯作者：
Kaskel, S.
中科院分区：
文献类型：
--
作者：
Hagen, M.;Schiffels, P.;Kaskel, S.
为了通过光谱获得有关Li-S反应机理的信息，进行了拉曼文献研究、多硫化物振动模式计算和实验原位测量。构建了一个特殊的测试单元，用于在 1.5 V 至 3.0 V 电压范围内充电和放电期间检查 100 cm(-1) 至 600 cm(-1) 光谱范围内的原位拉曼光谱。为了分配原位拉曼数据并支持对整个拉曼光谱中观察到的变化的解释，对明确定义的物质进行了多次参考测量。参考测量包括纯溶剂、电解质和由 S-8 和 Li2S 粉末的化学计量混合物制备的多硫化物溶液。观察到的拉曼光谱的分配进一步基于与在密度泛函理论 (DFT) 的 B3PW91/6-311G(2df,p) 水平上计算的多硫化物双阴离子 S-n(2-) 和自由基单阴离子 S-n(-) 的振动模式的纯理论数据的比较。振动光谱的 DFT 数据在可极化连续介质模型 (PCM) 的框架中校正了溶剂效应，从而可以识别原位拉曼光谱中的几个特征。 (C) 2013 年电化学协会。
To obtain information about the Li-S reaction mechanism through spectroscopy, a Raman literature study, polysulfide vibrational mode calculations and experimental in-situ measurements were performed. A special test cell was constructed to examine in-situ Raman spectra in the spectral range from 100 cm(-1) to 600 cm(-1) during charge and discharge in the voltage range of 1.5 V to 3.0 V. In order to assign the in-situ Raman data and to support the interpretation of the observed changes in the overall Raman-spectrum, several reference measurements on well-defined substances were conducted. The reference measurements included pure solvents, electrolytes and polysulfide solutions prepared from stoichiometric mixtures of S-8 and Li2S powders. The assignment of the observed Raman-spectra was further based on a comparison with purely theoretical data for the vibrational modes of the polysulfide di-anions S-n(2-) and radical mono-anions S-n(-) calculated at the B3PW91/6-311G(2df,p) level of density functional theory (DFT). The DFT data for the vibrational spectra, corrected for solvent effects in the framework of the polarizable continuum model (PCM), allowed an identification of several characteristic features in the in-situ Raman spectra. (C) 2013 The Electrochemical Society.