Our society is using ever more complex materials which often involve nanometre-scale morphology. From impurities or minor alloying additions at grain boundaries to nanostructured (composite) materials or the naturally nanostructured electrochemical interfaces: The detailed knowledge of structural and elemental distributions in the bulk as well as on/along the surfaces or interfaces becomes increasingly crucial for important technical developments. Our group aims to gain mechanistic insight into reactions of materials and interfaces related to energy materials. Research focusses on electrochemical interfaces, in particular related to positive electrodes of Li-Ion Batteries (LIB), but also on electrodeposition and corrosion including alloying and dealloying processes. We use a wide range of advanced characterization techniques to explore structural and elemental changes during reactions. Here we present a selection of examples of employing techniques such as synchrotron-based in-situ x-ray diffraction, Atom Probe Tomography (APT), or an electrochemical Surface Force Apparatus (SFA) for studies on Li-ion battery materials and fundamental corrosion.