Optimization of energy-storage properties for lead-free relaxor-ferroelectric (1-x)Na0.5Bi0.5TiO3-xSr0.7Nd0.2TiO3 ceramics

Ferroelectrics are considered as the most promising energy-storage materials applied in advance power electronic devices due to excellent charge-discharge properties. However, the unsatisfactory energy-storage density is the paramount issue that limits their practical applications. In this work, the excellent energy-storage properties are achieved in (1-x)Na0.5Bi0.5TiO3-xSr(0.7)Nd(0.2)TiO(3) ((1-x)NBT-xSNT) ferroelectric ceramics by a synergistic strategy, where SNT improves breakdown strength and enhances relaxation characteristic simultaneously. A high recoverable energy-storage density of 3.85 J cm(-3) and an energy-storage efficiency of 85.3% under an applied electric field of 305 kV cm(-1) are acquired in 0.5NBT-0.5SNT ceramic. Moreover, excellent temperature stability and frequency stability were also observed. The change rate of energy density is less than 10%, where the temperature and frequency in the range of 20-120 degrees C and 20-180 Hz, respectively. Meanwhile, an ultrahigh power density of 175 MW cm(-3) together with a fast discharge time of 136 ns is realized at 250 kV cm(-1). These excellent performances show that (1-x)NBT-xSNT ceramics have the potential to be used in pulsed power systems.