Operando Combined SAXS/XRD/XAFS Measurements of Lithium Conversion Battery

Many chemical reactions are accompanied by concerted phenomena, such as variance transition, structural changes, and particle formation. Various measurement techniques are employed to understand the whole picture of such concerted phenomena. A combination of small‐angle X‐ray scattering (SAXS), X‐ray diffraction (XRD), and X‐ray absorption fine structure (XAFS) is useful for studying concerted phenomena that occur, for example, inside rechargeable batteries. This combination can cover large lengths from 1 Å to several hundred nm. Operando measurements using this combination of methods can follow reactions during the charging and discharging of a rechargeable battery in a single experimental run. Fixed‐exit optics enable irradiation at the same point in a wide energy range. By employing 2D detectors for XRD and SAXS and using a quick XAFS technique, one can make the interval of each measurement sufficiently short to track various phenomena during charging and discharging. Here, an application of the system for alternating SAXS/XRD/XAFS measurements constructed in BL28XU, SPring‐8, Japan to the study of rechargeable batteries, is presented. The charge–discharge reaction in a conversion battery is a typical example of a cooperative phenomenon. In such batteries, changes in valence, crystal structure, and particle size occur concurrently. Here, it is shown that such concerted phenomena can be studied by almost simultaneously performing small‐angle X‐ray scattering, X‐ray diffraction, and X‐ray absorption fine structure measurements with synchrotron radiation.