X-ray imaging methods for multiscale characterization of batteries

X-ray imaging is transforming battery research by delivering multiscale insights into structure, composition, and chemistry, spanning micrometer to nanometer scales. As indispensable components of energy storage, electric vehicles, and mobile devices, batteries face significant challenges due to their intricate electrochemical processes, hierarchical architectures, and inaccessible components such as buried interfaces and air-sensitive materials. These complexities demand advanced techniques capable of uncovering localized effects and addressing the heterogeneity that often obscures critical phenomena. Advanced x-ray imaging techniques are rising to meet these demands, bridging knowledge gaps by providing detailed visualization of battery processes in ways that conventional methods cannot. Operando x-ray imaging, in particular, captures real-time changes during battery cycling; enabling researchers to observe dynamic processes and material transformations that are otherwise inaccessible. This approach overcomes the limitations of traditional destructive post-mortem analyses by offering a non-invasive, real-time window into battery operation. Recent advances in spatial resolution, computational power, and data analysis tools have made x-ray imaging increasingly accessible and effective for studying critical phenomena, such as buried interfaces, phase transitions, and surface-bulk differences. This work introduces four advanced x-ray imaging techniques, outlining their principles, capabilities, and contributions to battery research. These methods illuminate key processes, advance our understanding of battery behavior, and guide targeted performance improvements. Finally, we explore the future of x-ray imaging as a mainstream tool for addressing the pressing challenges in energy storage systems, emphasizing its pivotal role in guiding innovations for next-generation batteries.