Improved energy storage performance in rare-earth modified lead-free BNT-based relaxor ferroelectric ceramics

Dielectric ceramic capacitors with high energy storage performance are indispensable components in high-power pulse electronic systems. Herein, a collaborative optimization design is employed to achieve excellent energy storage performance in rare-earth oxides modified 0.76(0.94Bi(0.5)Na(0.5)TiO(3)-0.06BaTiO(3))-0.24Sr(0.7)Bi(0.2)TiO(3) (BNBT-SBT) ceramics by simultaneously enhancing the breakdown field strength (Eb) and relaxor behavior. To this end, ferroelectric domains are partially transformed into polar nanoregions by introducing relaxor ferroelectric SBT, while a smaller grain size is produced by doping rare-earth elements to improve the Eb and further disrupt the long-range order of ferroelectric polarization. It is found that the La-doped BNBT-SBT ceramic simultaneously exhibits a superior energy storage density of 4.4 J cm(-3)and an ultrahigh efficiency of similar to 91% under a moderate electric field of 300 kV/cm. The good temperature stability (30-120 degrees C), frequency endurance (1-100 Hz), electric fatigue resistance (1-10(6) cycles), and excellent power density (108 W cm(-3)) are also obtained in the lead-free Bi0.5Na0.5TiO3-based relaxor ferroelectric ceramics. These prominent properties indicate that the La-doped BNBT-SBT ceramic is a promising candidate for applications of high-energy storage capacitors. Published under an exclusive license by AIP Publishing.