Mechanochemical synthesis of solid-state electrolyte Sm1-xCaxF3-x for batteries and other electrochemical devices

Solid-state secondary batteries employing solid electrolytes provide the advantage to be potentially more stable than conventional batteries and hence are safer. At present, investigations of related ionic conductivities of solid ion conductors are attracting attention. In this work, we have prepared SmF3 with CaF2 doped materials. Different Sm1-xCaxF3-x compositions which are dependent on the stoichiometric ratio (0 <= x <= 0.15) had been obtained by planetary high-energy mechanochemical milling. Structural, morphology and ionic conductivities of the synthesized Sm1-xCaxF3-x electrolytes were examined. From X-ray diffraction (XRD) and Field Emission Scanning Electron Microscopy (FESEM), it was revealed that Sm1-xCaxF3-x constitutes in a tysonite-type structure with a crystallite size of around 10-20 nm and an average particle size of 50 nm. At room temperature, the highest ionic conductivity was achieved for Sm0.95Ca0.05F2.95 of 2.8.10(-5) S cm(-1). The corresponding activation energy was extracted to be 0.40 eV. Finally, a proof-of-principle solid-state Fluoride Ion Battery (FIB) had been tested based on a CeF3/Sm0.95Ca0.05F2.95/Bi electrochemical system. (C) 2019 Published by Elsevier B.V.