Designing and developing energy storage devices (ESDs) with remarkable performance and superior security call for in situ/operando characterization methods to get in-depth understanding of both working and failure mechanisms. However, the commonly used characterization techniques such as X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray spectroscopy and topography, and nuclear magnetic resonance (NMR) are based on bulk regions of electrodes or electrolytes which overlook the critical surface/interface behaviors.
A research team led by Prof. Qiang Fu from the Dalian Institute of Chemical Physics of the Chinese Academy of Sciences (CAS) reported the atmosphere-dependent relaxation and failure mechanisms on ESDs by in situ surface characterizations.
The results were published in J. Am. Chem. Soc. on Oct. 13th.
Relaxation in anhydrous atmospheres and failure in hydrous atmospheres have been visualized by in situ surface science methodology over an Al/graphite model battery
In recent years, Qiang Fu’s group devotes to developing and applying the in situ/operando surface science methodology, including electron spectroscopy and scanning probe microscopy, to explore the surface/interface chemistry of ESDs. The group has demonstrated the distinct surface effect based on the quantitative description of the electrochemical reactions by operando surface and interface analysis (Natl. Sci. Rev., 2021). In this work, based on the well-defined model batteries and the in situ characterization set-up with well-controlled atmospheres, atmosphere-dependent relaxation and failure processes in ESDs have been visualized by in situ Raman, XRD and XPS. For aluminum ion battery (AIB), the relaxation effects of the graphite electrode in anhydrous atmospheres are manifested by recoverable stage-structure change and electronic relaxation. The mechanisms can be described as the redistribution of the anion/cation pairs within graphite electrode by in situ XPS. Once exposure to hydrous atmospheres, H2O molecules from ambient can intercalate into the graphite electrode and hydrolysis reactions can be induced between newly intercalated H2O and ions. After H2O intercalation and hydrolysis, the failure behaviors of the graphite electrode happen as shown by the stage-structure degradation and electronic decoupling.
In addition, the operando/in situ surface/interface characterization methods have been successfully applied to study lithium-ion battery (LIB) systems. By dynamically investigating the surface/interface reactions of the LIB, the roles of the concentration and component of the electrolyte on the LIB’s performance have been further demonstrated (J. Energ. Chem., 20201). Based on the atmosphere-, temperature- and potential- controlled operando/in situ surface/interface techniques and well-defined model devices, such methods can be widely used to explore the working and failure mechanisms of metal-ion secondary batteries/supercapacitors and the interface reactions in metal-gas batteries.
This work has been supported by the National Natural Science Foundation of China (21825203, 21688102, 51872283, and 21733012), the National Key R&D Program of China (2016YFA0200200), the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB17020000), and the DICP&QIBEBT (UN201707 and UN201702). (Text by Chao Wang and Shiwen Li, Image by Guohui Zhang and Chao Wang)
Article link: https://pubs.acs.org/doi/abs/10.1021/jacs.1c09429