Phase evolution, dielectric thermal stability, and energy storage performance of NBT-based ceramics via viscous polymer process

There is an urgent need to develop stable and high-energy storage dielectric ceramics; therefore, in this study, the energy storage performance of Na 0.5- x Bi 0.46- x Sr 2 x La 0.04 (Ti 0.96 Nb 0.04 )O 3.02 ( x = 0.025–0.150) ceramics prepared via the viscous polymer process was investigated for energy storage. It was found that with increasing Sr 2+ content, the material transforms from a mixture of rhombohedral and tetragonal phases ( x = 0.025) to a mixture of orthorhombic and pseudo-cubic phases ( x = 0.15). The emergence of a dielectric plateau for the sample with x = 0.15 widens the applicability of the host compound. Finite element simulations show that a smaller grain size has a beneficial effect on the critical breakdown electric field and that the relaxor transformation benefits from the reduction of residual polarization ( P r ). The obtained ceramics achieve a value of 6.69 J/cm 3 for the energy storage density ( W rec ) and 89.48 % for the energy storage efficiency ( η ) under an applied electric field of 400 kV/cm, with a discharge time ( t 0.9 ) of 0.168 μs at 90 % of the energy under an electric field of 280 kV/cm, and a power density ( P d ) of 148 MW/cm 3 . This study shows a novel strategy for the modification of the dielectric and ferroelectric properties of NBT-based ceramics, providing an effective way to expand the operational temperature range and improve energy storage performance.