Improving energy storage properties of PbHfO₃-based antiferroelectric ceramics with lower phase transition fields

Dielectric energy storage devices are commonly used in applications involving high voltage levels. However, the presence of inherent risks and the costly insulation technology associated with these high voltages have emphasized the importance of improving energy storage density at lower electric fields. To achieve a high energy storage density at lower electric fields for antiferroelectric materials, it is necessary to decrease their antiferroelectric to ferroelectric phase transition electric fields (EAFE-FE) and acquire double hysteresis loops at lower electric fields. In this study, antiferroelectric ceramics were synthesized, specifically (Pb0.97La0.02)(HfxSn0.95-xTi0.05)O-3 (PLHST), using the tape-casting method. An important observation is that increasing the Hf4+ content in PLHST ceramics can effectively reduce the antiferroelectric to ferroelectric phase transition electric field, resulting in a significant increase in maximum polarization (P-max) and consequently leading to higher energy storage density. As a result, the (Pb0.97La0.02)(Hf0.6Sn0.35Ti0.05)O-3 antiferroelectric ceramic with a lower antiferroelectric to ferroelectric phase transition electric field of 15.4 kV mm(-1) can simultaneously exhibit an excellent recoverable energy storage density (W-rec) of 6.9 J cm(-3) and a high energy efficiency (eta) of 87.8%. Moreover, we introduce a merit value denoted as W-rec/EAFE-FE for further evaluation. A high W-rec/EAFE-FE value means that a material can achieve a large energy density under lower antiferroelectric to ferroelectric phase transition electric fields. Furthermore, charge-discharge tests indicate that this ceramic also demonstrates a superior discharge energy density (W-dis) of 5.3 J cm(-3) and a large power density (P-D) of 149.8 MW cm(-3). Additionally, both the recoverable energy storage density and energy efficiency exhibit outstanding frequency stability (1-100 Hz) and strong fatigue endurance (10 000 cycles). These above results collectively demonstrate that this work offers a promising antiferroelectric material for pulsed power applications at lower applied electric fields.