Direct hydrofluorothermal synthesis of sodium transition metal fluorosulfates as possible Na-ion battery cathode materials†
Abstract
Synthesis under hydrofluorothermal conditions produces new iron, manganese and vanadium fluorosulfates; these include the isomorphous Na3MIIIF2(SO4)2, M = V, Mn, Fe, with a sheet-like structure formed of linked MIIIF2O4 and SO4 polyhedra separated by sodium ions which may be extracted electrochemically at potentials of >3.5 V.