Boosting dielectric temperature stability in BNBST‐based energy storage ceramics by Nb2O5 modification

Exploring environment‐friendly energy storage ceramics simultaneously featuring large recoverable energy storage density (Wrec), high‐energy storage efficiency (ƞ), and excellent temperature stability is highly desirable for the application of pulsed power systems. Herein, Nb2O5 was introduced to modify BNBST‐based lead‐free relaxor ferroelectric ceramics in an effort to enhance the dielectric temperature stability. (Bi0.5Na0.5)0.65(Ba0.3Sr0.7)0.35(Ti0.98Ce0.02)O3 (BNBSTC) + x wt%Nb2O5 (0 ≤ x ≤ 4) ceramics were prepared by a solid‐state reaction method. The phase structure, microstructure, dielectric, and energy storage properties of the ceramics have been systematically studied. It was found that the εr–T curve was flattened, and the dielectric temperature stability was effectively improved due to the addition of Nb2O5. A noticeable Wrec (1.44 J/cm3) with high η (84.1%) was obtained in BNBSTC + 2 wt%Nb2O5 ceramics at a low electric field of 90 kV/cm, which was mainly due to a refined P–E loop induced by Nb2O5. In addition to excellent frequency and anti‐fatigue cycle stability, this ceramic provides a new solution for designing pulsed power capacitors with high energy density and high temperature stability under low voltage driving conditions.