Enhanced Energy-Storage Performance of High-Entropy (1 − x )(NaBiBa) 0.205 (SrCa) 0.1925 TiO ₃ - x Bi(Zn 2/3 Ta 1/3 )O ₃ Ceramic under Moderate Electric Field

Developing lead-free dielectric materials with superior energy-storage properties under medium electric fields is of critical significance for the advancement of compact pulsed-power electronics and wearable energy-storage devices. Herein, an optimization methodology integrating high-entropy engineering, bandgap modulation, and ion modification is proposed to design relaxor ferroelectric ceramics with (1− x )(NaBiBa) 0.205 (SrCa) 0.1925 TiO 3 − x Bi(Zn 2/3 Ta 1/3 )O 3 (shortened as NBBSCT- x BZT). Via collaborative A/B-site ion regulation, the as-prepared ceramics achieve optimized lattice distortion, enhanced breakdown strength, and pronounced relaxor characteristics. The optimized ceramic compositions exhibit exceptional energy-storage performances, while the 0.91 NBBSCT−0.09BZT sample achieves a superior W rec of 5.42 J/cm 3 and a comparably high η of 94.71% at 328 kV/cm. This work provides a feasible and effective strategy for designing high-performance lead-free dielectric specimens, offering a promising paradigm for their practical applications in moderate-voltage and flexible energy-storage fields.