Fluorine-ion conductivity of different technological forms of solid electrolytes R1–yMyF3–y (LaF3 Type ) (M = Ca, Sr, Ba; R Are Rare Earth Elements)

Abstract

We have investigated the conductivity of some representatives of different technological forms of fluoride-conducting solid electrolytes R_1–yM_yF_3–y (M = Ca, Sr, Ba; R are rare earth elements) with an LaF₃ structure: single crystals, cold- and hot-pressing ceramics based on a charge prepared in different ways (mechanochemical synthesis, solid-phase synthesis, and fragmentation of single crystals), polycrystalline alloys, etc. It is shown (by impedance spectroscopy), that different technological forms of identical chemical composition (R, M, y) exhibit different electrical characteristics. The maximum conductivity is observed for the single-crystal form of R_1–yM_yF_3–y tysonite phases, which provides (in contrast to other technological forms) the formation of true volume ion-conducting characteristics.