Optical Study of the Surface Film Formed during Li-Metal Deposition and Dissolution Investigated by Surface Plasmon Resonance Spectroscopy
Optical Study of the Surface Film Formed during Li-Metal Deposition and Dissolution Investigated by Surface Plasmon Resonance Spectroscopy
复制标题
通过表面等离子体共振光谱研究锂金属沉积和溶解过程中形成的表面膜的光学研究
DOI：
10.1021/acsami.2c04978
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发表时间：
2022
影响因子：
9.5
通讯作者：
and Hikaru Sano
中科院分区：
文献类型：
--
作者：
Mitsunori Kitta;Kazuki Yoshii;Kensuke Murai;and Hikaru Sano
在锂金属沉积和溶解循环期间电极表面膜的特征对于理解锂金属电池单元中的负电极反应机理是必不可少的。应在操作条件下研究反应初始阶段界面的物理和化学性质变化。在这项研究中，我们专注于锂金属电池负极的电极表面膜的光学性质的变化。铜基电化学表面等离子体共振光谱（EC-SPR）由于其对电极表面光学现象的高灵敏度和对锂金属沉积的稳定性而被应用。SPR反射凹陷的特征取决于电极表面的光学性质，即反射凹陷的波长和深度与电极表面膜的折射率和消光系数（颜色）直接相关，反射模拟证实了这一点。在操作EC-SPR实验中，在循环期间清楚地观察到光学性质的各种变化。特别地，消光系数的变化在第二过程中比Li-金属沉积的第一过程中更显著。通过电化学石英晶体微天平（EQCM）测量，表面膜形成过程中确认的第一个锂金属沉积过程。消光系数的显著变化是基于表面膜的颜色变化，这是由Li-金属沉积循环期间的化学条件变化引起的。
The features of the electrode surface film during Li-metal deposition and dissolution cycles are essential for understanding the mechanism of the negative electrode reaction in Li-metal battery cells. The physical and chemical property changes of the interface during the initial stages of the reaction should be investigated under operando conditions. In this study, we focused on the changes in the optical properties of the electrode surface film of the negative electrode of a Li-metal battery. Cu-based electrochemical surface plasmon resonance spectroscopy (EC-SPR) was applied because of its high sensitivity to optical phenomena on the electrode surface and its stability against Li-metal deposition. The feature of SPR reflectance dip depends on the optical properties of the electrode surface; namely, the wavelength and depth of the reflectance dip directly connected the refractive index and extinction coefficient (color of electrode surface film), which was confirmed by reflectance simulation. In the operando EC-SPR experiment, various changes in optical properties were clearly observed during the cycles. In particular, the change in the extinction coefficient was more remarkable at the second process than the first process of Li-metal deposition. By electrochemical quartz-crystal microbalance (EQCM) measurements, surface film formation was confirmed during the first Li-metal deposition process. The remarkable change in the extinction coefficient is based on the color change of the surface film, which is caused by the chemical condition change during Li-metal deposition cycles.