Oliver Clemens1
Uni Stuttgart1
The Fluoride Ion Battery (FIB) is an alternative all-solid-state battery technology based on the shuttling of fluoride ions, which is currently investigated for its potential impact for future energy storage. FIBs can be based on conversion- (metal to metal fluoride transformation) or intercalation-type materials (insertion of fluoride into vacant anion sites), which possess certain advantages and disadvantages related to their different chemical working principle.<br/>With respect to intercalation-based materials, various Ruddlesden-Popper-type materials have been examined due to their capability to incorporate two fluoride ions per redox-active transition-metal M, corresponding to a transformation from A<sub>2</sub>MO<sub>4</sub> to A<sub>2</sub>MO<sub>4</sub>F<sub>2</sub>. Such compositional changes do not only induce structural changes, but can also alterate intrinsic properties connected to the electron configuration (e. g., magnetism or superconducting properties), which makes them of interest to achieve reversible tuning of functional properties.<br/>In this contribution, an overview will be given about materials used for FIBs. We will discuss how the electrochemical methods can be used in order to prepare novel oxyfluorides, which are not accessible via conventional chemical routes, what will be required in order to achieve high cycling stability of this battery system, and how this technology can give access to electrochemically tunable functional properties within a class of materials that cannot be altered by conventional battery routes.