The achievement of high recoverable energy density (Wrec) and efficiency (η) simultaneously in dielectric ceramics under low/moderate electric fields (E's) offers potential for use in compact microelectronics and portable devices. However, a major challenge lies in the difficulty of coexistence of high maximum polarization (Pm) and low polarization hysteresis under low/moderate E's. Here, through the modification of heterovalent ferroelectric-active ions to enhance average ionic polarizability, guarantee considerable spontaneous polarization, and disrupt long-range ferroelectric order, both the high Pm and low polarization hysteresis were obtained in the 0.80(Bi0.47Na0.47Ba0.06)TiO3-0.20Sr(Fe0.5Nb0.5)O3 relaxor ferroelectric ceramics, leading to an excellent energy storage performance with Wrec of 6.17 J/cm3 and η of 90.3% under a moderate field of 34 kV/mm. In addition, the ceramics exhibit a high and temperature-stable permittivity (εr) as well as low dielectric loss, where εr (150 °C) reached 2085 with the temperature coefficient of capacitance (TCC) ≤ ±15% over 18 to 260 °C, and the tanδ at 150 °C is as low as 0.0075. This ceramic system exhibits potential in dielectric energy-storage capacitor systems for practical applications.
Zhou et al. (Wed,) studied this question.