Effects of La-induced phase transition on energy storage and discharge properties of PLZST ferroelectric/antiferroelectric ceramics

(Pb_1–1.5xLa_x)[Zr_0.65Sn_0.20Ti_0.15]O₃(x = 0.02, 0.04, 0.06, 0.08) ceramics were fabricated via traditional solid-state reaction method and the La-induced phase transition was confirmed. It was found increasing La content will stabilize the antiferroelectric phase, improving the energy storage and discharge properties. When x = 0.02, the composition is normal ferroelectric phase and when x = 0.04, the dielectric is antiferroelectric but can be induced to metastable ferroelectric phase under external electric field. When x = 0.06 and 0.08, the dielectric is normal antiferroelectric and has higher energy density, efficiency and discharge current. Also, the stored charge in antiferroelectrics is released completely in sub-microsecond due to their low remanent polarization. However, for ferroelectric materials, the stored charge is more, but only small part can be released, resulting in lower discharge current. When x = 0.08, the discharge current density and peak power density of the composition can be as high as 436 A/cm² and 13 MW/cm³ under 60 kV/cm, respectively, indicating its potential for decoupling and pulsed capacitors.