High energy density, temperature stable lead-free ceramics by introducing high entropy perovskite oxide

Dielectric capacitors with fast charge–discharge rate and high power density are drawing more attention in pulse power equipment field. In this work, bismuth-based high entropy compound (HEC), Bi(Zn0.2Mg0.2Al0.2Sn0.2Zr0.2)O3 (BZMASZ), was introduced into BaTiO3-Na0.5Bi0.5TiO3 (BT-NBT) matrix, in order to improve the comprehensive energy storage performance. The addition of BZMASZ induced phase transition from tetragonal phase to cubic phase, along with the enhancement of relaxor behavior and local nanodomains. The 0.1 BZMASZ modified 0.75BT-0.25NBT ceramics exhibited excellent recoverable energy density of Wrec ~ 3.74 J/cm3, high conversion efficiency of η ~ 82.2 % and superior temperature stability of ± 4.5 % from −30 to 200 °C. Combined with the high power density of PD ~ 34.76 MW/cm3 and rapid discharge rate of t0.9 ~ 67 ns, the x = 0.1 ceramics are considered to be the promising candidate for future wide-temperature pulse power applications.