Fluoride-Ion Conductivity Analysis Of Yb-F-S Multiple-Anion Compounds

The mixed-anion fluorosulfide Yb3F4S2 was examined as a solid electrolyte for all-solid-state fluoride-ion batteries. The synthesized Yb3F4S2 compound by solid-state reaction under vacuum contained Yb2O2S impurities, which originated from the starting materials. The conduction properties of Yb3F4S2 are discussed herein based on the electrochemical impedance and DC blocking measurements, which indicate mixed ionic and electrical conduction of Yb3F4S2. Yb L3-edge X-ray absorption measurements demonstrate the mixed valence state of ytterbium ion.