A novel Sr_(5)BiTi_(3)Nb_(7)O_(30) 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 Sr_(5)BiTi_(3)Nb_(7)O_(30)(SBTN)tungsten bronze relaxor ferroelectric ceramic is pre­pared and explored for potential energy storage applications.A high recoverable energy density Wrec(~3.72 J/cm^(3))and ultrahigh efficiencyη(~94.2%)at 380 kV/cm are achieved simultaneously.Both Wrec andηexhibit superior stabilities against temperature(30-140°C),cycles(100-105)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.