BS_0.5BNT-based relaxor ferroelectric ceramic/glass–ceramic composites for energy storage

Relaxor ferroelectric ceramics have very high dielectric constant (ε_r) but relatively low electrical breakdown strength (E_b), while glass–ceramics exhibit higher E_b due to the more uniformly dispersed amorphous phases and submicrocrystals/nanocrystals inside. How to effectively combine the advantages of both relaxor ferroelectric ceramics and glass–ceramics is of great significance for the development of new dielectric materials with high energy storage performance. In this work, we firstly prepared BaO–SrO–Bi₂O₃–Na₂O–TiO₂–Al₂O₃–SiO₂ (abbreviated as GS) glass powders, and then fabricated (Ba_0.3Sr_0.7)_0.5(Bi_0.5Na_0.5)_0.5TiO₃ + x wt% GS ceramic composites (abbreviated as BS_0.5BNT–xGS, x = 0, 2, 6, 10, 14, 16, and 18). Submicrocrystals/nanocrystals with a similar composition to BS_0.5BNT were crystalized from the glass, ensuring the formation of uniform core–shell structure in BS_0.5BNT–xGS relaxor ferroelectric ceramic/glass–ceramic composites. When the addition amount of GS was 14 wt%, the composite possessed both high ε_r (> 3200 at 1 kHz) and high E_b (≈ 170 kV/cm) at room temperature, and their recoverable energy storage density and efficiency were W_rec = 2.1 J/cm³ and η = 65.2%, respectively. The BS_0.5BNT–14GS composite also had several attractive properties such as good temperature, frequency, cycle stability, and fast charge–discharge speed. This work provides insights into the relaxor ceramic/glass–ceramic composites for pulsed power capacitors and sheds light on the utilization of the hybrid systems.