Enhancement of energy storage performance in NaNbO3 and Sm3+ modified BNT-based ceramics

Dielectric capacitors of excellent performance will possess high recoverable energystoragedensity (Wrec) and energy efficiency (η), and operate stably in extreme environments, such as at high temperature, high electric field intensity, and high frequency. In this study, lead-free relaxor ferroelectric(1-x)(0.85Bi0.5Na0.5TiO3–0.15Ba0.94Sm0.06TiO3) –xNaNbO3[(1-x)(BNT-BSmT)–xNN)] ceramics were prepared by a traditional solid phase sintering method to achieve excellent energy storage performance. The addition of Sm3+and NN locally disrupted the long-range ordered structure of the domain and inhibited grain growth due to limited grain boundary diffusion.The recoverable energy storage density and energy efficiency of the sample with an NN doping content ofx = 0.12 reached 2.42 J/cm3 and 81.18% at an applied electric field of 170 kV/cm, respectively. The efficiency remained stable (∼80%) at variable frequency (0.1–100 Hz) and temperature (20–140 °C). Furthermore, the0.88(0.85BNT–0.15BSmT)–0.12NN ceramic underwent rapid charge and discharge processes and achieved high power density (41.5 MV/cm3) at fast discharge rates (1.39 J/cm3). The new lead-free relaxor ferroelectric ceramics involved inthis study have great potential applications in the pulse capacitor field and a large temperature range.