Realizing excellent energy storage properties in Na0.5Bi0.5TiO3-based lead-free relaxor ferroelectrics

Abstract

Development of lead-free dielectric capacitors with high recoverable energy storage density (Wrec), large energy storage efficiency (η), and wide usage temperature range are in high demanded for pulse power systems. Herein, we realized the enhancement of energy storage properties [high Wrec = 3.76 J/cm3, large η = 78.80 %, and broad operating temperature range (20−180 °C)] in lead-free Na0.5Bi0.5TiO3 (BNT)-based relaxor ferroelectrics via component regulation. Excellent energy storage properties mainly originate from suppressing early polarization saturation and improving dielectric breakdown strength (Eb). Domain evolution on the nanoscale offers robust support to suppression of early polarization saturation. The enhancement of Eb can be derived from the contribution of the Mg-rich phase, which is also corroborative via first-principles calculation on basis of density functional theory (DFT). We believe that these findings in this work may provide a practicable guideline to build new lead-free ceramics for electrical energy storage applications.