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

A series of (1-x)(Sr0.7Ba0.3)(5)LaNb7Ti3O30-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 (W-re) of 0.77 J/cm(3) 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 W w in the temperature range of -55 *C to 125 degrees C is less than 15 % compared to room temperature. Short discharge period (similar to 0.17 mu s), high power density (61.2 MW/cm(3)) and high discharge energy density (2.45 J/cm(3)) were evaluated by charge-discharge tests. Excellent thermal stability, high energy storage efficiency and high power density indicate that 0.7(Sr0.7Ba0.3)(5)LaNb7Ti3O30-0.3(Bi0.5Na0.5)TiO3 ceramic is a promising pulse capacitor for working over a wide temperature range.