Enhanced energy storage properties of La³⁺ modified 0.92Bi_0.5Na_0.5TiO₃ -0.06Ba(Zr_0.2Ti_0.8)O₃-0.02NaNbO₃ ternary ceramic system

The development in field of hybrid vehicles, telecommunication and energy sectors require dielectric materials having high-energy storage density with optimum thermal stability to operate in certain environment. To fulfil such requirement a new set of materials along the ternary solid solutions of 0.92Bi_0.5(1-x)-La_(x)Na_0.5TiO₃ -0.06Ba(Zr_0.2Ti_0.8)O₃-0.02NaNbO₃ (NB_1-xL_xT-BZT-NN) (x = 0, 0.03, 0.05, 0.07) were fabricated through solid-state mix oxide route. The XRD patterns analysis confirmed a structural phase transformation from rhombohedral to the tetragonal-P4bm phase when x content increased from 0 to 0.07. The SEM study revealed, dense microstructure for all ceramics accompanied by a decrease in the average grain from 1.66 μm to 1.05 μm leading to high densities for these materials with an increase in the x content. The dielectric breakdown field increased from ∼115 to 137 kV cm⁻¹ resulting in an increase in recoverable energy density from ∼0.68 to 1.14 J cm⁻³ with the increase in x content. Furthermore, excellent temperature stability (±15%) in dielectric permittivity was observed in a wide temperature range for each ceramic. In the present study, a recoverable energy density of 1.14 J cm⁻³ along with an efficiency of 70.6% was obtained for the composition of x = 0.07. (paper)