NSRRC Activity Report 2023

056 NSRRC ACTIVITY REPORT 2023 S ynchrotron-based techniques are revolutionizing the field of energy materials. With their remarkable analytical capabilities, these techniques are becoming an essential part of the material development process. Scientists are using synchrotron-based techniques like X-ray powder diffraction, X-ray absorption spectroscopy, and X-ray photoelectron spectroscopy to analyze crystal and chemical structures for a better understanding of materials. The high penetrating power of X-rays has led to the development of unique experimental platforms that allow researchers to explore dynamic mechanisms in electrochemical processes. These in situ synchrotron-based experimental techniques have become well-known among research teams. By modifying materials, employing different synthesis techniques, and varying the types of compound dopants, researchers can use similar analytical approaches to achieve improved device performance. The techniques mentioned above are based on understanding how the material behaves on a wide-area average. Until recently, there has been no suitable technique to clearly analyze electrochemical processes at interfaces between different materials, in the distribution of heterogeneous samples, in hierarchical materials, or even within a single crystal grain. However, thanks to the new generation of low- divergence synchrotron light source, Taiwan Photon Source (TPS), X-rays can now be focused down to the scale of tens of nanometers. This breakthrough development has opened new avenues for scientists to explore. In Fig. 1(a) , the X-ray nanodiffraction beamline, TPS 21A , provides an 80 × 80 nm focused white/mono X-ray source for experiments. This beamline uses a 4-bounce channel-cut monochromator (4BCM) and allows users to quickly switch between white and monochromatic X-ray sources by keeping both light paths overlapped at the same position. The monochromatic X-ray energy range is from 5.5 to 28 keV. The experimental endstation operates in a high vacuum system and a scanning electron microscope is integrated for fast sample positioning and real-time morphology analysis. The beamline is equipped with various detectors and can perform nanoscale X-ray Laue Fig. 1 : Concept of valence mapping through pre-edge shifting of the Fe K-edge XAS results of one particle (a) in the LFP@OCV + Super P (carbon) mixture across a to f, (b) in the LFP@100% SOC + Super P (carbon) mixture, (c) in the LFP@OCV + LPSC mixture, and (d) in LFP@ 100% SOC + LPSC. [Reproduced from Ref. 9] Exploring the Potential of Spatially Resolved X-ray Techniques in Advancing Energy Science Microscopic study of solid−solid interfacial reactions in all-solid-state batteries achieved improved device performance.