Abstract
This brief review first introduces the reversible solid oxide cell (RSOC) concept, the types of devices that this covers, the most important materials used until now, and the level of early market introduction of these devices. Next, a more detailed description of classic materials for electrolyte, fuel electrode, fuel electrode supports, oxygen electrode and their shortcomings is presented, and in each case followed by a picture of ongoing materials R&D with clear potential for alleviating the shortcomings, in particular initiatives, which can decrease the RSOC operation temperature to about 500 °C or below. Finally, perspectives of RSOC in conversion and storage of renewable energy are sketched.