Development of an Evaluation Method for a Lithium/Electrolyte Interface Based on X-ray Reflectivity and Grazing Incidence X-ray Scattering Measurements

Development of an Electrochemical Cell for In Operando Characterization of Lithium/Electrolyte Interface Using X‐Ray Total Reflection

“…Therefore, the critical angle θ c of the Li/electrolyte interface of this cell before reduction and oxidation was determined to be 0.039 . This value is in good agreement with that reported in the study by Kimura et al [25] Furthermore, there was no significant change in the shape of the reflectivity curve measured after applying a current of 0.1 A m À2 . In fact, the critical angle was about 0.038 , which is almost the same as that before the redox reaction.…”

“…The intensities of the reflected X-rays were measured as a function of θ h before and after the redox reaction, as shown in Figure 4a. The obtained reflectivity curves are similar to those reported by Kimura et al, [25] that is, a clear and sharp decrease in reflectance is observed at around θ h ¼ 0.04 . This behavior confirms that X-ray total reflection occurs on the electrolyte side of the interface.…”

“…This behavior was also observed in a previous study as a bright line in the 2D detector and is considered to have information on the interface structure of the electrolyte side. [25] The E we -t graph is shown in Figure 6, which was obtained in synchronization with the GIXS measurements. A symmetrical redox cycle curve was obtained, indicating that the electrochemical performance of the developed cell is reasonable.…”

“…In this context, we previously developed an evaluation method for the Li/electrolyte interface using the X-ray total reflection [25] and succeeded in observing total reflection X-rays from the electrolyte side of the Li/electrolyte interface. It was confirmed that the reflectivity curve exhibited an abrupt drop at the critical angle θ c with increasing incident angle, which was in good agreement with θ c calculated from the densities of Li metal and the electrolyte.…”

“…The obtained scattering pattern included signals reflecting the structure of the electrolyte on the interfacial region. However, structural variations of the electrolyte near the interface in an operating battery have not been investigated by this method, as the charging and discharging system was not implemented to the cell described in the study by Kimura et al [25] In this study, we have developed a new cell of an LMB for the in operando characterization of the electrolyte side of the Li/electrolyte interface using X-ray total reflection. We measured the reflected X-rays from the electrolyte side of the Li/electrolyte interface using the cell we developed.…”