Realizing enhanced energy storage performance of Na0.47Bi0.47Ba0.06TiO3-based relaxors with weak coupling behavior by manipulating phase fraction

Abstract

Lead-free dielectric capacitors have attracted considerable attention as the core energy storage element of pulsed power systems due to their advantages of fast charging capability, high power density and environmental friendliness. However, the low recoverable energy storage density (Wrec) and narrow operating temperature range have become the bottleneck technical problems limiting its practical application. In this work, a class of weakly coupled relaxor ferroelectrics with excellent Wrec (9.06 J/cm3) and energy storage efficiency (η ∼ 85.3 %) were designed and prepared by manipulating phase fraction. Moreover, the materials exhibit excellent temperature stability with regard to energy storage, with a change in Wrec and η of less than 8 % over a wide temperature range (25 °C − 200 °C). The introduction of Sm(Mg0.5Hf0.5)O3 (SMH) enhances the insulating properties while refining the grains, effectively increasing the breakdown field strength (Eb) of the material. The emergence of weakly coupled nano-microdomains has the effect of suppressing the nonlinear polarization response of the material, which in turn results in a high polarization difference (ΔP). The preceding work presents a universal strategy for the future design and preparation of BNT-based lead-free dielectric capacitors with high energy storage properties (ESP) and good temperature stability.