''Revealing complex materials structure by synchrotron x-rays''
Understanding materials morphological, chemical, and structural evolution is crucial for designing materials for desired structure and properties. Multi-modal and multi-dimensional characterization at synchrotrons can provide unprecedented information for complex, heterogeneous materials system. A multi-modal approach combines multiple synchrotron techniques to gain complementary information. Furthermore, with imaging techniques specifically, multi-dimensional imaging includes techniques such as tomography, spectroscopic microscopy, or in situ/operando imaging. These capabilities are particularly powerful when used to study complex structures with morphological and chemical heterogeneity. This talk will discuss the applications of these synchrotron X-ray approaches in two types of such systems – porous materials fabricated by dealloying and energy storage materials in batteries. Dealloying, a selective etching process, can be used to fabricate a variety of nanoporous metals with a characteristic bi-continuous structure with promising applications in catalysis, energy storage and bio-sensing. The bi-continuous patterns do not exist in the alloy prior to the dealloying process, but rather form dynamically via an elegant self-organizing process. Our work includes addressing the processing-structure correlation in different dealloying systems, from solid-state interfacial dealloying, chemical dealloying, molten salt corrosion, and vapor phase dealloying. We utilized advanced synchrotron-based X-ray nano-tomography, both full-field and scanning techniques. In addition, by combining X-ray imaging techniques with other modalities, we use an X-ray multi-modal characterization approach to address the complex chemical, morphological and structural evolution in energy storage materials. Specifically, novel systems with nanoporous electrode design, beyond-lithium batteries and aqueous batteries, will be discussed. These works highlight how synchrotron X-ray methods can advance our understanding in complex materials for future materials design.