Synthesis of Nano-Sized Solid Electrolyte PrSryF and the Effect of Heat Treatment on the Ionic Conductivity of Fluoride Nanoceramics

Solid electrolyte nanoceramics Pr Sr y F ( y = 0.03, sp. gr. ) were obtained by high-energy milling of melt-grown crystals, followed by cold pressing. The phase composition, microstructure, morphology, and electrical properties of nanoceramics were studied using X-ray diffraction analysis, electron microscopy, and impedance spectroscopy. The room-temperature conductivity of the synthesized Pr 0.97 Sr 0.03 F 2.97 nanoceramics (σ cer = 1.7 × 10 −7 S/cm) is much lower than the conductivity of the original single crystal (σ crys = 4.0 × 10 −4 S/cm), which is due to its low (~75% of the theoretical value) density. Heat treatment of nanoceramics at 823 K in vacuum leads to a threefold increase in σ cer , and annealing at 1273 K in a fluorinating atmosphere results in further increase in conductivity (σ ce r = 4.3 × 10 −5 S/cm) due to the collective recrystallization and significant increase in the ceramics density (up to 90%). The mechanical milling and subsequent heat treatment of Pr Sr y F nanopowder make it possible to process single-phase highly conductive ceramics. The proposed method for the synthesis of ceramic fluoride nanomaterials as a technological form of solid electrolytes is a promising way for further developments in the field of creating fluorine-ion current sources and fluorine gas sensors.