Dielectric, ferroelectric, and energy storage properties in dysprosium doped sodium bismuth titanate ceramics

In this work, Na0.5(Bi1-xDyx)0.5TiO3 (0 ≤ x ≤ 15%) ceramics were prepared via solid state reaction method and were characterized. A stable and pure perovskite phase was revealed by X-ray diffraction analysis for all compositions and a symmetry change from rhombohedral to orthorhombic phase was detected beyond 10% of Dy substitution. The incorporation of Dy3+ into Sodium Bismuth Titanate (Na0.5Bi0.5TiO3) matrix allows a substantial decrease of the coercive field, an increase in the resistivity, and leads to a high stability of the dielectric permittivity (∆ɛ/ɛ(150 °C) ≤ ± 15%) over a wide temperature range. Furthermore, this system was found to exhibit improved energy storage properties at high temperatures with a maximum energy density of 1.2 J/cm3 obtained for 2%Dy composition at 200 °C. The obtained results are very promising for energy storage capacitors operating at high temperatures.