Superior energy storage properties with thermal stability in lead-free ceramics by constructing an antiferroelectric/relaxor-antiferroelectric crossover

Fast development of electrostatic capacitors requires dielectric materials to perform large energy storage densities with high efficiency over a wide temperature range. Although antiferroelectric materials hold great potentials for achieving superior energy storage effect due to the field-induced antiferroelectric-ferroelectric transition, the strongly first-order transition is inevitably accompanied with a low energy storage efficiency and inferior thermal stability. Here, we found that a high polarization change and low hysteresis can be simultaneously achieved in a crossover composition between antiferroelectric and relaxor antiferroelectric states. As a result, a large recoverable energy storage density (Wrec ∼ 8.6 J/cm3) with high efficiency (η ∼ 85%) is obtained in lead-free Ag1-3xLaxNb0.9Ta0.1O3 (x=0.03) ceramics under 460 kV/cm. The x=0.03 ceramics also exhibit excellent energy storage properties (Wrec > 6.8 J/cm3 with ultrahigh η ∼ 90%) in the temperature range of 20-120°C. This promising energy storage effect of the antiferroelectric crossover composition arises from the coexistence of micro- and nano-antiferroelectric domains, which can persist over a wide temperature range. Our work may push forward the development of high-performance lead-free antiferroelectric dielectrics for energy storage devices.