An effective strategy for enhancing energy storage density in (Pb1−1.5xGdx)(Zr0.87Sn0.12Ti0.01)O3 antiferroelectric ceramics

Abstract

Antiferroelectric materials play an important role in dielectric energy storage because of their unique phase transition characteristics, high saturated polarization, and almost zero remanent polarization. However, their low energy storage capacity limits their applications. Here, an integrated strategy for enhancing energy storage density by using the designed composition of antiferroelectric materials is proposed. By doping Pb(Zr_0.87Sn_0.12Ti_0.01)O₃ with a new dopant Gd³⁺, a high recoverable energy storage density of 12.0 J cm⁻³ at 447 kV cm⁻¹ was achieved, along with a moderate energy storage efficiency of 78%. This result is obtained by co-optimising the breakdown strength and phase-switching the electric field together with the maximum polarization. The enhanced breakdown strength is a result of the grain refinement (as found through simulation by finite element analysis) and an increased band gap. By adjusting the tolerance factor, the antiferroelectric phase was stabilized, which in turn improved the phase-switching field. Finally, the polarization was strengthened from sample Gd0 to Gd2, as the breakdown strength was increased, and there were fewer oxygen vacancies to hinder domain switching, which were caused by increasing cation vacancies due to Gd³⁺ doping. Moreover, excellent temperature stability in the 30–100 °C range and good fatigue behaviour up to 12 000 cycles were obtained, along with a high discharge energy density of 8.2 J cm⁻³. Because of these characteristics, the (Pb_0.97Gd_0.02)(Zr_0.87Sn_0.12Ti_0.01)O₃ ceramic is a promising candidate for high-performance pulsed-power capacitor applications.