Multimodal and Operando Synchrotron X-ray Characterization for Advanced Energy Materials

Advancing our fundamental knowledge of energy materials for future applications requires a mechanistic understanding of their morphological, chemical, and structural transformations. This presentation highlights the key role of multimodal and operando synchrotron X-ray characterization in advancing our understanding of these complex systems. We will discuss three categories of materials as examples, including beyond Li-ion batteries, materials used in extreme environments, such as those involving molten salts and thermal cycling, and nanoarchitecture thin films created by solid-state dealloying. For beyond Li-ion batteries, including aqueous Zn ion batteries and non-aqueous sodium metal batteries, synchrotron techniques unravel the intricate mechanisms of chemical conversion, dissolution/redeposition, and plating/stripping. Operando techniques such as powder diffraction, absorption spectroscopy, and fluorescence microscopy, complemented by synchrotron X-ray nano-tomography, illuminate the dissolution-deposition mechanisms and the evolution of interfacial morphology and chemistry in these batteries [1, 2]. Extending this approach to materials undergoing transformation at elevated temperatures, we will further discuss our work in molten salts and thermochemical materials. These are critical for energy applications like concentrated solar power, nuclear reactors, and thermal energy storage. Our research investigates the dealloying, coarsening, corrosion, and structural reformation of metals and alloys in molten salts, as well as thermochemical materials undergoing chemical changes through thermal cycling. By employing a suite of synchrotron techniques and correlating them with electron microscopy, our research studies the morphological changes and structural alterations, providing insights into the degradation mechanisms at play [3, 4]. Our research also explores the innovative process of solid-state dealloying to create nanoarchitectured thin films. This technique selectively removes specific elements from alloys, leading to the formation of bicontinuous nanostructures with unique properties. These nanoarchitectured materials exhibit enhanced surface areas and distinct mechanical, chemical, and physical characteristics, making them suitable for various energy applications, including catalysis, batteries, and sensors. Through the application of machine-learning materials design, synchrotron X-ray multimodal characterization, we analyze the morphological evolution and structural integrity of these materials, offering new insights into the design of nanoarchitectured thin films [5-7]. Overall, the findings not only contribute to the fundamental understanding of material behaviors but also guide the development of more resilient and efficient energy materials, addressing some of the most pressing challenges in energy sustainability. Journal inside front cover art depicting a green battery for aqueous Zn/MnO2 battery and multi-modal synchrotron characterization to study advanced batteries [1]. Operando X-ray nano-tomography and scanning transmission electron microscopy revealing materials morphology evolution in molten salt [3]. Journal inside front cover art and schematics depicting the design and discovery of the solid-state metal dealloying through the machine-learning method and multimodal synchrotron X-ray experiments [4].