High strain and energy-storage density across a wide temperature range in fine PbHfO3 ceramics

Antiferroelectric materials exhibit fantastic application potential in multifunctional devices due to their special structure and polarization/strain-electric field responses. However, it has long been challenging to realize multifunctionality in PbHfO ₃ , one of the prototypical antiferroelectrics, due to its poor sinterability and structural complexity. To address these issues, we report an effective strategy to obtain fine and dense PbHfO ₃ ceramics by the solid-state reaction method involving a liquid phase sintering mechanism. The crystal structure, microstructure, phase transitions, energy storage, and strain performance are systematically investigated. A high recoverable energy density W _reco (7.29 J/cm ³ ) and a large strain (0.51%) are achieved with a temperature-stable (25 ∼ 175 °C) feature. By combination of synchrotron and laboratorial X-ray diffraction, Raman spectroscopy, dielectric and impedance spectroscopy, and density-functional-theory calculations, the high and temperature-stable energy-storage and strain properties are determined to arise from the stable antiferroelectric nature of PbHfO ₃ with a large polarization in a broad temperature range and its transformation to a ferroelectric phase with R3 c symmetry under electric field. Furthermore, the ceramics present a negative temperature coefficient of resistance in a higher temperature range of 400 ∼ 600 °C. These performances grant PbHfO ₃ antiferroelectric ceramics a huge potential for applications in high-density energy storage capacitors, large-displacement actuators, and temperature sensors and compensators over a broad temperature range.