Revealing Evolution in Electrochemical and Thermal Battery Materials with Synchrotron X-Ray Microscopy and Multimodal Analysis

Synchrotron X-ray microscopy and multimodal analysis offer critical tools for deepening our mechanistic understanding of electrochemical and thermal battery materials for energy applications and future sustainability. X-ray microscopy provides direct visualization and quantification of morphological changes and associated chemical transformations in these materials. By combining X-ray microscopy with complementary synchrotron X-ray analyses, including diffraction, scattering, and spectroscopy, as well as other microscopy techniques like electron microscopy, we can gain a holistic view of the morphological, structural, and chemical changes through this multimodal approach. This presentation aims to discuss the applications of such approaches across a range of electrochemical and thermochemical batteries, connecting diverse systems with common characterization needs and approaches, which could be applicable to a wider scientific community.<br/><br/>We will emphasize electrochemical energy storage, including aqueous Zn ion batteries, non-aqueous sodium metal batteries, and the model system of Cu pulse deposition, which can be used for designing novel battery electrodes. Synchrotron microscopy reveals the complex mechanisms of chemical conversion, dissolution/redeposition, and plating/stripping. Operando synchrotron X-ray fluorescence microscopy, along with X-ray nano-tomography conducted by transmission X-ray microscopy, illustrates the dissolution-deposition mechanisms and the evolution of interfacial morphology and chemistry in these batteries. Additionally, Grazing-Incidence Wide-Angle X-ray Scattering and Soft X-ray Absorption Spectroscopy offer further capabilities to analyze electrochemical interfaces, including the surface of the metal deposits and the solid electrolyte interphase (SEI) layer. The development of X-ray microscopy methodologies involving machine learning has led to super-resolution imaging and mitigated issues for radiation-sensitive systems, which will also be discussed.<br/><br/>Extending X-ray microscopy studies to materials that transform at high temperatures, we will discuss our research on molten salts and thermochemical materials. These are vital for energy applications, including thermal energy storage, also known as thermal batteries. Our research investigates the chemical and structural evolution processes of metals and alloys in molten salts, as well as the redox processes of thermochemical materials undergoing thermal cycling. By employing operando synchrotron X-ray nano-tomography, X-ray Absorption Near Edge Structure (XANES) imaging, and X-ray absorption spectroscopy, coupled with electron microscopy analysis, our research sheds light on the morphological and chemical changes, illuminating degradation mechanisms with the aim of improving the longevity of thermal batteries.