Excellent thermal stability, high efficiency and high power density of (Sr0.7Ba0.3)5LaNb7Ti3O30–based tungsten bronze ceramics

Abstract A series of (1-x)(Sr0.7Ba0.3)5LaNb7Ti3O30–x(Bi0.5Na0.5)TiO3 (x = 0.1-0.4) ceramics with tungsten bronze structure were prepared by solid state reaction. Phase composition, microstructure and energy storage properties were studied. When x = 0.3, excellent thermal stability satisfying the X7R specification was obtained and its energy storage as well as charge-discharge performances were further evaluated. Release energy density (Wre) of 0.77 J/cm3 and an energy storage efficiency of 97.3% were detected at a low electric field of 20 kV/mm. Under the electric field of 10 kV/mm, the change of Wre in the temperature range of −55 °C to 125 °C is less than 15% compared to room temperature. Short discharge period (∼0.17 μs), high power density (61.2 MW/cm3) and high discharge energy density (2.45 J/cm3) were evaluated by charge-discharge tests. Excellent thermal stability, high energy storage efficiency and high power density indicate that 0.7(Sr0.7Ba0.3)5LaNb7Ti3O30–0.3(Bi0.5Na0.5)TiO3 ceramic is a promising pulse capacitor for working over a wide temperature range.