Electrically Induced Phase Transitions and Dielectric Relaxation Characteristics in Fe ₂ O ₃ ‐Modified Bi 0.5 Na 0.5 TiO ₃ ‐SrTiO ₃ Ceramics

Lead‐free (1‐ x )(0.65Bi 0.5 Na 0.5 TiO 3 ‐0.35SrTiO 3 )‐ x Fe 2 O 3 (BNST‐ x F) ceramics ( x = 0–0.08) were successfully synthesized via solid‐state reaction, aiming to develop environmentally friendly high‐performance energy storage materials. The study systematically reveals how Fe 2 O 3 doping optimizes the functional properties of BNST‐based ceramics. All samples retained a pure perovskite structure with dense microstructures and clear grain boundaries. Notably, Fe 2 O 3 doping significantly enhanced the energy storage density, relaxation behavior, and breakdown strength compared with pure BNST. At higher doping levels ( x ≥ 0.06), an electric‐field‐induced phase transition occurred, accompanied by antiferroelectric‐like P – E hysteresis within 15–70 kV/cm, attributed to electric‐field‐regulated dipole ordering. Dielectric analysis identified two distinct relaxation mechanisms below and above x = 0.06, originating from polar nanoregions (PNRs) and oxygen vacancies (VOs), respectively. This study reveals the microscopic mechanism of doping‐induced phase transition and relaxation dynamics, providing a feasible strategy for designing high‐performance lead‐free energy storage ceramics.