Enhancing the dielectric and energy storage properties of lead-free Na0.5Bi0.5TiO3-BaTiO3 ceramics by adding K0.5Na0.5NbO3 ferroelectric

A novel strategy of enhancing the dielectric and energy storage properties of Na0.5Bi0.5TiO3-BaTiO3 (NBT-BT) ceramics by introducing a K0.5Na0.5NbO3 (KNN) ferroelectric phase is proposed herein, and its underlying mechanism is elucidated. The lead-free KNN ceramic decreases the residual polarisation and increases the electric breakdown strength of the NBT-BT matrix through the simultaneous modification of its A-sites and B sites. The obtained NBT-BT-x-KNN ceramics have a perovskite structure with unifying grains. A bulk 0.9NBT-BT-0.1KNN ceramic sample with a thickness of 0.2 mm possesses a high energy storage density of 2.81 J/cm(3) at an applied electric field of 180 kV/cm. Moreover, it exhibits good insulation properties and undergoes rapid charge and discharge processes. Therefore, the obtained 0.9NBT-BT-0.1KNN ceramic can be potentially used in high-power applications because of its high energy density, good insulation properties, and large discharge rate.