Excellent energy storage properties in (Bi_0.4Na_0.2K_0.2Ba_0.2)(Ti_0.95Zr_0.05) O₃-based high-entropy ceramics by introduction of Sr(Mg_1/3Nb_1/3Ta_1/3)O₃ medium-entropy endmember

In this study, a series of high-entropy lead-free relaxor ferroelectrics (1-x)(Bi0.4Na0.2K0.2Ba0.2)(Ti0.95Zr0.05)O-3-xSr(Mg1/3Nb1/3Ta1/3)O-3 are designed and synthesized. As x increases, the corresponding configurational entropy (triangle S-config) varies from 1.53 R to 2.10 R. The long-range ordered structure of the ferroelectric domains is disrupted, accompanied by the reduced remanent polarization (P-r) and the improved W-rec. When x = 0.09, a high recoverable energy density W-rec of 3.83 J/cm(3) and a high energy storage efficiency eta of 85.7 % were obtained at an electric field of 360 kV/cm. In addition, the 0.91BNKBTZ-0.09SMNT ceramic sample has excellent performance stability under different temperatures (30-180 degrees C), cycle times (1-10(4) times) and frequencies (1-100 Hz), making it a reliable candidate as a dielectric for pulsed power systems.