High Ionic Conductivity of K5-Xtlx(Mg0.5hf1.5)(Moo4)6 (0 ≤ Х ≤ 5)Solid Solutions

Novel K 5- x Tl x (Mg 0.5 Hf 1.5 )(MoO 4 ) 6 (0 ≤ х ≤ 5) oxides were successfully synthesized by solid state reaction. The results indicate the formation of a continuous series of solid solutions with the NASICON-like structure (sp. gr. R [[EQUATION]] c ) in the composition range 0 < x < 5. The unit-cell parameters of the solid solutions increase linearly with composition, as a consequence of thallium substitution for potassium. The cation conductivity of Tl 5 Mg 0.5 Hf 1.5 (MoO 4 ) 6 has been shown to exceed the conductivity of the parent potassium magnesium hafnium molybdate. The highest total conductivity of 2.49 × 10 –3 S/cm was found at 831 K for Tl 5 Mg 0.5 Hf 1.5 (MoO 4 ) 6