Currently, dielectric capacitors with superior charge-discharge performance, long lifetime, and high power density are drawing increasing attention, especially for lead-free ferroelectrics due to their environmental friendliness, multi-functional applications and excellent energy storage properties. In this work, lead-free relaxor ferroelectric Sr(MgTa)O (SMT)-modified NaBiTiONaNbO (NBT-NN) bulk and thick film ceramics were prepared via solid-state reaction and tape-casting approaches, respectively, and their energy storage characteristics were tailored via multiple optimization strategies. A high recoverable energy density (∼5.20 J/cm) and efficiency (∼82.24 %) at 380 kV/cm were obtained for bulk ceramics. In addition, an ultrahigh recoverable energy density (∼17.24 J/cm) with a high efficiency (∼82.02 %) at 1200 kV/cm was obtained in thick film ceramics, which are attributed to the improvement of dielectric breakdown strength (DBS) and the transformation to the relaxor ferroelectrics. Moreover, the excellent temperature (30–130 °C) and frequency (0.5–500 Hz) stabilities were also obtained at 600 kV/cm.

中文翻译：

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通过多种优化策略在无铅 Na0.5Bi0.5TiO3-NaNbO3 基陶瓷中实现超高能量存储密度

目前，具有优异充放电性能、长寿命和高功率密度的介电电容器越来越受到人们的关注，特别是无铅铁电体由于其环境友好、多功能应用和优异的储能性能而受到越来越多的关注。在这项工作中，分别通过固态反应和流延成型方法制备了无铅弛豫铁电Sr(MgTa)O (SMT)改性NaBiTiONaNbO (NBT-NN)块体和厚膜陶瓷，并研究了它们的储能特性通过多种优化策略进行定制。块状陶瓷在 380 kV/cm 下获得了高可恢复能量密度（∼5.20 J/cm）和效率（∼82.24%）。此外，厚膜陶瓷在1200 kV/cm下获得了超高可恢复能量密度（∼17.24 J/cm）和高效率（∼82.02%），这归因于介电击穿强度（DBS）的提高和向弛豫铁电体的转变。此外，在 600 kV/cm 下也获得了优异的温度（30–130 °C）和频率（0.5–500 Hz）稳定性。