Li Qinghao, Yan Shishen, Yang Wanli
Advanced Light Source, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, California 94720, USA.
School of Physics, National Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China.
J Chem Phys. 2020 Apr 14;152(14):140901. doi: 10.1063/5.0003311.
Interfacial behaviors and properties play critical roles in determining key practical parameters of electrochemical energy storage systems, such as lithium-ion and sodium-ion batteries. Soft x-ray spectroscopy features shallow penetration depth and demonstrates inherent surface sensitivity to characterize the interfacial behavior with elemental and chemical sensitivities. In this review, we present a brief survey of modern synchrotron-based soft x-ray spectroscopy of the interface in electrochemical energy storage systems. The technical focus includes core-level spectroscopy of conventional x-ray absorption spectroscopy and resonant inelastic x-ray scattering (RIXS). We show that while conventional techniques remain powerful for probing the chemical species on the surface, today's material research studies have triggered much more demanding chemical sensitivity that could only be offered by advanced techniques such as RIXS. Another direction in the field is the rapid development of various in situ/operando characterizations of complex electrochemical systems. Notably, the solid-state battery systems provide unique advantages for future studies of both the surface/interface and the bulk properties under operando conditions. We conclude with perspectives on the bright future of studying electrochemical systems through these advanced soft x-ray spectroscopic techniques.
界面行为和性质在决定电化学储能系统（如锂离子电池和钠离子电池）的关键实际参数方面起着至关重要的作用。软X射线光谱具有浅穿透深度，并表现出固有的表面敏感性，能够以元素和化学敏感性来表征界面行为。在本综述中，我们简要介绍了基于现代同步加速器的电化学储能系统界面软X射线光谱。技术重点包括传统X射线吸收光谱的芯能级光谱和共振非弹性X射线散射（RIXS）。我们表明，虽然传统技术在探测表面化学物种方面仍然很强大，但当今的材料研究对化学敏感性提出了更高的要求，而这只有像RIXS这样的先进技术才能提供。该领域的另一个方向是复杂电化学系统的各种原位/操作表征的快速发展。值得注意的是，固态电池系统为未来在操作条件下研究表面/界面和体相性质提供了独特的优势。我们最后展望了通过这些先进的软X射线光谱技术研究电化学系统的光明前景。
