Insight into Structural and Electrical Properties of Potassium and Lithium Substituted Non-stoichiometric Sodium Bismuth Titanate (Na0.54Bi0.46TiO3-δ)

Abstract

Sodium bismuth titanate (Na 0.5 Bi 0.5 TiO 3 ) has been reported as a fast oxide ion conductor. Sodium rich non-stoichiometric Na 0.54 Bi 0.46 TiO 3-δ has also been reported to have good oxide ion conductivity. Here, we report the influence of Potassium (K) and Lithium (Li) doping on the A-site (i.e. Na site) of the Na 0.54 Bi 0.46 TiO 3-δ system. XRD results revealed the formation of perovskite rhombohedral phase having R3c space group. SEM study showed the existence of dense morphology in the sintered samples. TGA technique is performed to estimate the oxygen deficiency in the investigated system. Impedance results suggested an increase in the bulk conductivity by doping of potassium; however, a decrease in the conductivity was observed for Li-doping on A-site. A correlation between the structural and electrical properties have been established to explain the conductivity behaviour. Further, threedimensional oxide ion diffusion mechanism was also studied using the bond valance energy (BVE) technique.