Organised by Carlos Escudero (scientist at BL16-NOTOS, ALBA Synchrotron) and Juan Jesús Velasco (beamline responsible at BL15-3Sbar, ALBA Synchrotron).

Understanding the behavior of energy-related materials under realistic operating conditions is essential for the rational design of more efficient systems for energy conversion and storage. The chemical composition, oxidation states, and structural evolution at interfaces and in the bulk are all determined by the surrounding environment, which ultimately controls the material's functionality. However, capturing this information during operation remains highly challenging, as the harsh conditions required for many processes—such as high pressures, liquid electrolytes, or reactive gas atmospheres—are often incompatible with traditional analytical methods.

Synchrotron-based X-ray techniques have become powerful, non-destructive tools to address this challenge, offering element-specific insights into electronic structure, oxidation states, and chemical speciation from bulk to surface. Despite their potential, applying these techniques under operando or in situ conditions, particularly in electrochemical or catalytic environments. In recent years, significant progress has been made toward adapting synchrotron methodologies to probe working systems under relevant conditions.

This symposium will highlight recent advances in in situ and operando synchrotron X-ray techniques for the study of energy materials, including electrocatalysts, battery electrodes, and systems for hydrogen production and CO₂ conversion, among other. Emphasis will be placed on both methodological innovations and their application to technologically relevant processes, aiming to bridge the gap between materials characterization and functional understanding under working conditions.