Excellent energy storage properties and multi-scale regulation mechanism of Sr(Zr0.5Ti0.5)O3-(Na0.5Bi0.5)0.94Ba0.06TiO3 ceramics

Abstract

With the rapid advancement of energy storage technologies, dielectric capacitor materials with the outstanding recoverable energy density and power density have garnered significant attention from researchers in the past decades. In this study, (1-x) (Na0.5Bi0.5)0.94Ba0.06TiO3-xSr(Zr0.5Ti0.5)O3 ceramics were prepared via a solid-state reaction method, and the impact of composition on their structure, energy storage performance and stability were investigated. The results revealed that the introduction of Sr(Zr0.5Ti0.5)O3 induced the ferroelectric-relaxor transformation of (Na0.5Bi0.5)0.94Ba0.06TiO3 ceramics, leading to the destruction of the long-range ferroelectric order and the formation of polar nanoregions. In addition, the 0.7(Na0.5Bi0.5)0.94Ba0.06TiO3–0.3Sr(Zr0.5Ti0.5)O3 ceramic exhibited the optimal comprehensive energy storage performance: its recoverable energy storage Wrec attained 8.19 J/cm3 at 650 kV/cm, while the energy storage efficiency η was 85.6 %. Meanwhile, it displayed exceptionally high power density (315.7 MW/cm3) and charge-discharge rate (t0.9 = 50.4 ns). Moreover, this ceramic demonstrated the impressive energy storage performance, in particular, good temperature stability across a wide range of temperatures (20–140 °C), frequency stability (1–200 Hz), and fatigue resistance (1–106 cycles). Finite element analysis showed an enhancement in the breakdown field strength of the ceramics was attributed to the reduction in grain size. First-principles calculations revealed that the band gap increased after adding Sr and Zr elements, and the interactions between the states of O 2p and Ti 3d, Zr 3d, Bi 6p may serve as the microscopic origin of electron energy level polarization and enhanced dielectric performance. Thus, the ceramics have great potential for the application in high-power pulsed electronic systems.