Achieving exceptional energy storage performance in PbHfO3 antiferroelectric ceramics through defect engineering design

Antiferroelectric (AFE) ceramics exhibit significant potential for diverse applications in pulsed power capacitors, chiefly owing to their electric field-induced AFE-ferroelectric (FE) phase transitions. However, their lower intrinsic breakdown strength (BDS) frequently results in dielectric breakdown prior to the field-induced phase transition, critically undermining their energy storage performance. Herein, we introduced a high-performance PbHfO₃ (PHO)-based AFE ceramic developed through a defect engineering strategy that successfully reduced the concentration of oxygen vacancies within the ceramic via non-equivalent substitution of Ta⁵⁺ ions in a high valence state. This approach not only mitigated the leakage current density associated with the migration of free electrons and ions but also improved the electrical homogeneity of the ceramic and curtailed grain growth, culminating in a substantial increase in BDS. Moreover, in terms of microstructure, the local chemical disorder was induced by this method facilitated dipole flipping, resulting in an increased maximum polarization (P_max) and reduced hysteresis width. Consequently, the (Pb_0.97La_0.02)(Hf_0.6Sn_0.4)_0.975Ta_0.02O₃ (PLHST2) ceramic achieved an exceptional energy storage density of approximately 13.15 J cm^-3 and a high efficiency of around 83.6% at 680 kV cm^-1. This accomplishment not only highlights the considerable potential of PHO-based AFE ceramics for use in pulsed capacitors but also paves the way for future advancements in the energy storage capabilities of dielectric ceramics.