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Na 0.5 Bi 0.5 TiO 3 -based relaxor ferroelectric ceramics have attracted widespread attention due to their potential applications in energy storage capacitors for pulse power system. We herein propose a synergistic strategy of introduction of 6s2 lone pair electrons, breaking the long-range ferroelectric order, and band structure engineering for high performance energy storage by introducing Bi(Mg 0.5 Sn 0.5)O 3 (BMS) with weak ferroelectric active cations into 0.7Na 0.5 Bi 0.5 TiO 3 -0.3SrTiO 3 (BNT-ST) to form BNT-ST-BMS ceramics. The doped ceramics display the excellent dielectric stability versus temperature and frequency. The suitable BMS doping can increase the band gap of the BNT-ST ceramic and effectively avoids early dielectric breakdown and polarization saturation. The BNT-ST-BMS ceramic in the composition of x = 0.08 exhibits an outstanding recoverable energy storage density (W rec) of 5.99 J/cm3, together with a good efficiency (ƞ) of 76% as well as an excellent dielectric stability versus temperature (Δε r /ε r(150°C) ≤ ±15%) and frequency. The findings in this work demonstrate that the BNT-ST-BMS ceramics have exceptional potential as candidate materials for pulse power and high voltage capacitors applications, and provide a path for the development of the other lead-free energy storage materials. [ABSTRACT FROM AUTHOR]

Na 0.5 Bi 0.5 TiO 3 -based relaxor ferroelectric ceramics have attracted widespread attention due to their potential applications in energy storage capacitors for pulse power system. We herein propose a synergistic strategy of introduction of 6s2 lone pair electrons, breaking the long-range ferroelectric order, and band structure engineering for high performance energy storage by introducing Bi(Mg 0.5 Sn 0.5)O 3 (BMS) with weak ferroelectric active cations into 0.7Na 0.5 Bi 0.5 TiO 3 -0.3SrTiO 3 (BNT-ST) to form BNT-ST-BMS ceramics. The doped ceramics display the excellent dielectric stability versus temperature and frequency. The suitable BMS doping can increase the band gap of the BNT-ST ceramic and effectively avoids early dielectric breakdown and polarization saturation. The BNT-ST-BMS ceramic in the composition of x = 0.08 exhibits an outstanding recoverable energy storage density (W rec) of 5.99 J/cm3, together with a good efficiency (ƞ) of 76% as well as an excellent dielectric stability versus temperature (Δε r /ε r(150°C) ≤ ±15%) and frequency. The findings in this work demonstrate that the BNT-ST-BMS ceramics have exceptional potential as candidate materials for pulse power and high voltage capacitors applications, and provide a path for the development of the other lead-free energy storage materials. [ABSTRACT FROM AUTHOR]

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/cm3) 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 R 3 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. High performances of Pb (1+x) HfO 3 for multifunctional applications [Display omitted] [ABSTRACT FROM AUTHOR]