Outstanding energy density and charge-discharge performances in Sr2KNb5O15-based tungsten bronze ceramics for dielectric capacitor applications

Relaxor ferroelectric ceramics are extremely encouraging materials for energy storage capacitor applications in pulse equipment. As the second largest ferroelectric ceramic system, tungsten bronze structure relaxor ferroelectric ceramics have emerged as a significant contender and garnered significant attention in the pulse capacitor research field. In this work, an Sb-modified Sr2KNb5O15-based tungsten bronze relaxor ferroelectric ceramic system is designed to explore its energy storage potential. XRD refinement reveals the declines in the oxygen octahedra tilting and distortion after the introduction of Sb, which significantly augments the relaxation behavior. Additionally, refined grain size and reduced oxygen vacancy concentration are observed, greatly improving the breakdown strength. Consequently, a superior energy storage density (similar to 4.57 J/cm(3)) accompanied by wonderful energy storage efficiency (similar to 89.3 %) is received at 540 kV/cm, with wide frequency stability and great thermal stability. Moreover, amazing discharging performances are also achieved with rapid discharge speed (tau(0.9) < 70 ns), towering discharge current density (815.2 A/cm(2)) and surprising power density (130.4 MW/cm(3)). All these performances indicate that the designed Sr2KNb5O15-based tungsten bronze relaxor ferroelectric ceramic can be one encouraging option in the dielectric energy storage field.