Tunable polarization-drived superior energy storage performance in PbZrO 3 thin films

Abstract

Antiferroelectric PbZrO₃ films have great potential to be used as the energy storage dielectrics due to the unique electric field-induced phase transition character. But the phase transition process always accompanies polarization hysteresis effect that induces large energy loss and lowers the breakdown strength, leading to inferior energy storage density as well as low efficiency. In this work, the synergistical strategies by doping smaller ions of Li⁺-Al³⁺ to substitute Pb²⁺ and lowering the annealing temperature from 700℃ to 550℃ are proposed to change the microstructure and tune the polarization character of PbZrO₃ films, excepting to dramatically improve the energy storage performances. The prepared Pb_(1-x)(Li_0.5Al_0.5)_xZrO₃(abbreviated as P_(1-x)(L_0.5A_0.5)_xZO) films exhibit ferroelectric-like (<em>FE</em>) rather than antiferroelectric (<em>AFE</em>) character once the doping content of Li⁺-Al³⁺ ions reaches 6 mol%, accompanying a significant improvement of energy storage density of 49.09 J/cm³,but energy storage efficiency is only 47.94% due to the long-correlation of ferroelectric domains. Accordingly, the low-temperature annealing is carried out to reduce the crystalline degree and the polarization loss. P_0.94(L_0.5A_0.5)_0.06ZO films annealed at 550℃ deliver a linear-like polarization rather than ferroelectric-like behavior annealed at 700℃, the lowered remanent polarization as well as improved breakdown strength (4814 kV/cm) result in the superior energy storage density of 58.7 J/cm³ and efficiency of 79.16%, simultaneously possessing excellent frequency and temperature stability, and good electric fatigue tolerance.