“…High Li + conductivity has been reported for several Li compounds, such as oxides, sulfides, , oxyhalides, , and chloride materials. , Recently, mixed alkali compounds, such as NaI-NaBH 4 -LiI and KLiTaO 6 , wherein other alkali cations coexist with Li + ions, have been reported to be promising solid electrolytes. , For solid electrolytes, high Li + conductivity, high electrochemical stability, air stability, and superior mechanical properties are required for their practical applications in all-solid-state LIBs. Fluoride compounds are a new class of materials that are expected to meet these requirements. − The wide electrochemical stability window of fluorides ensures the use of high-voltage cathodes together with anode materials with low operating voltages, such as graphite and Li metal .…”