Structure, Antiferroelectricity and Energy-Storage Performance of Lead Hafnate in a Wide Temperature Range.

Lead hafnate (PbHfO 3 ) has attracted a lot of renewed interest due to its potential as antiferroelectric (AFE) material for energy storage. However, its room temperature (RT) energy-storage performance has not been well established and no reports on the energy-storage feature of its high-temperature intermediate phase (IM) are available. In this work, high-quality PbHfO 3 ceramics were prepared via the solid-state synthesis route. Based on high-temperature X-ray diffraction data, the IM of PbHfO 3 was found to be orthorhombic, Imma space group, with antiparallel alignment of Pb 2+ ions along the [001] cubic directions. The polarization-electric field (P-E) relation of PbHfO 3 is displayed at RT as well as in the temperature range of the IM. A typical AFE loop revealed an optimal recoverable energy-storage density ( W rec ) of 2.7 J/cm 3 , which is 286% higher than the reported data with an efficiency (η) of 65% at 235 kV/cm at RT. A relatively high W rec value of 0.7 J/cm 3 was found at 190 °C with an η of 89% at 65 kV/cm. These results demonstrate that PbHfO 3 is a prototypical AFE from RT up to 200 °C, making it a suitable material for energy-storage applications in a wide temperature range.