Improving energy storage performance of (Bi0.5Na0.5)0.94Ba0.06TiO3-based high-entropy ceramics by A/B-site Co-regulation

Due to the novel high-entropy effects, entropy engineering strategies have been widely implemented in perovskite dielectric ceramics to improve their comprehensive energy storage performance. In this study, by designing (Bi 0.5 Na 0.5 ) 0.94 Ba 0.06 ) 0.75 (Ca 0.5 Sr 0.5 ) 0.25 TiO 3 matrix and co-doping of Nd 3+ at A-site and (Zr 1/3 Hf 1/3 Sn 1/3 ) 4+ at B-site, novel (Bi 0.5 Na 0.5 ) 0.94 Ba 0.06 TiO 3 -based high-entropy ceramics (HECs) are developed to optimize energy storage performance. The results reveal that the configuration entropy can be improved by co-regulation of A/B-site compositions, and the increased entropy can promote the suppression of grain size, the enhancement of dielectric relaxation and impedance, and the widening of band gap, giving rise to small remanent polarization and great breakdown strength ( E b ). Eventually, the composition with the maximum entropy of 1.92R exhibits superior recoverable energy storage density ( W rec  ∼ 6.84 J/cm 3 ) and high efficiency ( η  ∼ 82.9 %) at a large E b  ∼ 597 kV/cm, as well as good temperature stability, frequency stability and charge-discharge characteristics. These findings imply that designing high-entropy systems through A/B-site co-regulation is an effective approach for developing high-performance energy storage devices.