Boosting dielectric temperature stability in BNBST‐based energy storage ceramics by Nb ₂ O ₅ modification

Abstract Exploring environment‐friendly energy storage ceramics simultaneously featuring large recoverable energy storage density ( W rec ), high‐energy storage efficiency ( ƞ ), and excellent temperature stability is highly desirable for the application of pulsed power systems. Herein, Nb 2 O 5 was introduced to modify BNBST‐based lead‐free relaxor ferroelectric ceramics in an effort to enhance the dielectric temperature stability. (Bi 0.5 Na 0.5 ) 0.65 (Ba 0.3 Sr 0.7 ) 0.35 (Ti 0.98 Ce 0.02 )O 3 (BNBSTC) + x wt%Nb 2 O 5 (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 ε r –T curve was flattened, and the dielectric temperature stability was effectively improved due to the addition of Nb 2 O 5 . A noticeable W rec (1.44 J/cm 3 ) with high η (84.1%) was obtained in BNBSTC + 2 wt%Nb 2 O 5 ceramics at a low electric field of 90 kV/cm, which was mainly due to a refined P–E loop induced by Nb 2 O 5 . 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.