Successful PhD Defense by Ava Rajh
On Tuesday, March 11, our colleague, young researcher Ava Rajh, a PhD student in Physics, convincingly defended her doctoral dissertation entitled "Characterization of structural changes in batteries by X-ray Raman and emission spectroscopy"
The thesis presents the development and application of novel characterization methodologies for studying structural and chemical changes in next generation battery technologies. This research focuses on the development and application of photon-in/photon-out spectroscopies, in particular X-ray Raman Scattering (XRS) and Laboratory X-ray Emission Spectroscopy (XES), which are used to circumvent certain limitations of the conventional X-ray absorption spectroscopy.
XRS is a non-resonant inelastic photon scattering technique that overcomes the shallow probing depth limitations of traditional soft X-ray methods, enabling analysis of light elements in bulk samples and operando measurements. It was implemented for the study of structural changes in carbon anodes during Na-ion battery discharge/charge cycle and to characterize the electrochemical processes in metal-organic batteries.
On the other hand XES enables the use of laboratory excitation sources and, when paired with high-resolution crystal Bragg spectrometers, it can achieve chemical characterization comparable to the conventional synchrotron-based XAS. The feasibility of XES was demonstrated by tracking the chemical state of sulfur and characterizing sulfur species during the charge/discharge cycles of Li-S batteries.
