Energy Storage and Dielectric Properties of PbHfO3 Antiferroelectric Ceramics

Antiferroelectric (AFE) materials are regarded as one of the most hopeful candidates for pulse power capacitors due to their higher saturation polarization, lower remnant polarization, high power density, and fast charge–discharge speed. It is difficult to simultaneously obtain excellently the recoverable energy density (W rec) and the energy efficiency (η) at present. In this work, PbHfO3 AFE ceramics are processed by the cold isostatic pressure (CIP) method. It is confirmed that the CIP method can reduce the grain sizes and ameliorate the ceramic’s microstructure and thus increase the average electric breakdown field strength up to 336 kV/cm compared to 269 kV/cm by the conventional solid-state (CS) method. An excellent W rec of 11.4 J/cm3 with a high η of 88.2% is achieved in the PbHfO3 ceramics by the CIP method at 342 kV/cm. Furthermore, it exhibits good stability in temperature and frequency and has a high discharge current density of 1557 A/cm2 and power density of 233 MW/cm3 with a rapid discharge speed (112 ns). Moreover, dielectric properties and Raman spectra of the sample by the CIP method are discussed and demonstrate that the sample encounters a phase transformation at 150 and 195 °C. The result in this work indicates that the PbHfO3 AFE ceramics by the CIP method will be a potential candidate for pulse power capacitors.