Synthesis and characterization of Ca (1− x ) Sm x F (2+ x ) (0 ≤ x ≤ 0.15) solid electrolytes for fluoride‐ion batteries

Calcium fluoride solid electrolytes have been identified as a candidate for solid‐state fluoride‐ion batteries (FIBs). Here, we investigate the doping of CaF 2 with samarium — Ca 1− x Sm x F 2 +x (0 ≤  x  ≤ 0.15) — obtained by solid synthesis via high‐energy ball milling. Structural, morphological, and ionic conductivity studies of the as‐prepared materials were examined. It reveals that the fluorite‐type structure is dominating with a crystallite size of 12–14 nm. The highest ionic conductivity at room temperature had been obtained for Ca 0.95 Sm 0.05 F 2.95 with a value of 2.8 × 10 −6  S·cm −1 . It proves that a small content of Sm doping can considerably improve the ionic conductivity of CaF 2 .