Superior energy storage performance of BNT-based ferroelectric ceramics based on maintaining high polarization and breakdown strength

Bi[Formula: see text]Na[Formula: see text]TiO3 (BNT)-based lead-free ceramics with superior ferroelectric properties are considered to be extremely advantageous in energy storage capacitors for future green technologies. Here, we demonstrate an approach to achieve both ultrahigh energy density [Formula: see text] and efficiency [Formula: see text] by regulating the multiscale electropolar structures and microstructure. A satisfactory energy storage performance of a high [Formula: see text] of [Formula: see text], and a decent [Formula: see text] of 80% under [Formula: see text] are attained in the 0.5(BNT-CS)-0.5SB[Formula: see text]T ceramic (abbreviated as BNT-0.2SBT). Moreover, BNT-0.2SBT exhibits superior power density ([Formula: see text]), ultrafast discharge time ([Formula: see text][Formula: see text]ns) at [Formula: see text], and good temperature stability. The findings in this work not only demonstrate that a valid candidate, but also provide a new idea of how to achieve both high-energy storage density and efficiency in lead-free ferroelectric materials.