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(Zn_0.2Mg_0.2Al_0.2Sn_0.2Zr_0.2)O₃ (BZMASZ), was introduced into BaTiO₃-Na_0.5Bi_0.5TiO₃ (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 W_rec ~ 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 P_D ~ 34.76 MW/cm³ and rapid discharge rate of t_0.9 ~ 67 ns, the x = 0.1 ceramics are considered to be the promising candidate for future wide-temperature pulse power applications.