In this presentation, the application of transmission electron microscopy (TEM) to battery materials will be discussed. Non-aqueous batteries are in the core of the currently ongoing electrification of transport and improvements in the grid. Lithium-ion battery technology is a practically dominant battery technology at the moment, but the focus in battery research is also shifting to post-lithium batteries including ones based on sodium, potassium, calcium, magnesium and aluminium. The bulk processes occurring in battery electrode materials are the key to understanding the functioning and mechanisms in different types of batteries. In addition, battery electrodes are usually complex multi-component systems that include active materials, conductive additives and binders. Localised structural and chemical analysis is therefore very important in relevant studies. The use of imaging, diffraction, scanning transmission electron microscopy, spectroscopies (x-ray energy dispersive spectroscopy and electron energy loss spectroscopy) is able to reveal useful scientific information on the structure and processes in battery materials. Recent developments in in-situ TEM holders allows researchers to observe real time changes in realistic battery cells placed directly into the TEM column.