A novel Sr₅BiTi₃Nb₇O₃₀ tungsten bronze ceramic with high energy density and efficiency for dielectric capacitor applications

Dielectric capacitors with high capacitive energy storage are urgently needed to meet the growing demand for high-performance energy storage devices. Herein, a novel lead-free Sr5BiTi3Nb7O30 (SBTN) tungsten bronze relaxor ferroelectric ceramic is prepared and explored for potential energy storage applications. A high recoverable energy density W-rec (similar to 3.72 J/cm(3)) and ultrahigh efficiency eta (similar to 94.2%) at 380 kV/cm are achieved simultaneously. Both W-rec and eta exhibit superior stabilities against temperature (30-140 degrees C), cycles (10(0) -10(5)) and frequency (1-500 Hz). In addition, a high current density of 796 A/cm(2) and a large power density of 71.7 MW/cm(3) are achieved, together with good thermal endurance and fatigue resistance. These results demonstrate that the obtained SBTN ceramic can be deemed as the promising candidates for dielectric capacitor applications.