Unraveling Working and Degradation Mechanisms of Energy Storage and Conversion Materials at the Nanoscale Using Synchrotron X-Ray Characterizations.

A comprehensive understanding of working and degradation mechanisms of energy materials is essential for enhancing their performance and tackling contemporary energy and environmental challenges, particularly in the transition from fossil fuels to renewables. Emerging nanoscale X-ray characterization techniques based on synchrotron radiation provide robust, multi-scale, and multi-modal analytical capabilities, making them a suite of powerful tools for revealing operational and failure mechanisms, especially of bulk materials with features ranging from nano to micrometers under realistic operating conditions. This Perspective initially highlights the advantages of X-ray methods based on synchrotron light sources and then summarizes X-ray-matter interactions and corresponding characterization methods. Three pivotal approaches that facilitate nanoscale X-ray imaging are subsequently summarized. Representative examples illustrate the versatility and power of these prominent techniques, including X-ray imaging, scattering/diffraction, and spectroscopy, in probing morphologies, compositions, atomic structures, and electronic properties. Integration of multi-scale and multi-modal X-ray techniques is underscored to achieve synergistic enhancements in analytical depth. It concludes with a discussion of current challenges, emerging opportunities, and future directions, providing insights into potential advancements in this field.