Improved energy storage properties of BNT-based ceramics by compositing with tungsten bronze phase

Dielectric layer based on ceramic is very important for energy storage capacitors. Composite ceramics are one of the important materials for enhancing energy storage capacity. The tungsten bronze-structured (Sr_0.7Ba_0.3)₅LaNb₇Ti₃O₃₀ (SBLNT)-doped (Bi_0.5Na_0.5)TiO₃ (BNT) perovskite ceramics were proposed in this work and further modified by Ta. The phase transition of BNT-based ceramics from ferroelectric to relaxor ferroelectric was achieved at room temperature by SBLNT and Ta. An excellent recoverable energy storage density of 2.4 J/cm³ and efficiency of 80% were obtained at 0.8 wt% Ta content and 140 kV/cm. The practical discharge obtained high discharge energy density of 2.00 J/cm³ and power density of 61.2 MW/cm³. Therefore, the composite ceramics constructed by perovskite and tungsten bronze phases have great potential in energy storage capacitors.