Enhanced energy storage performances under low electric fields in (1 − x) Na0.5Bi0.5TiO3–xSr0.7Bi0.2(Al0.5Ta0.5)O3 relaxor ferroelectric ceramics: impact of Sr0.7Bi0.2(Al0.5Ta0.5)O3 on structure and electrical properties

Abstract

Dielectric ceramic capacitors (DCCs) that can achieve high recoverable energy storage density (W_rec) under relatively low electric fields (LEFs) hold great potential for applications in microelectronic devices. In this work, a series of (1 − x)Na_0.5Bi_0.5TiO₃–xSr_0.7Bi_0.2(Al_0.5Ta_0.5)O₃ [(1 − x)NBT–xSBAT, x = 0.00–0.20] relaxor ferroelectric ceramics were prepared utilizing a traditional solid-state sintering method. A comprehensive investigation was conducted on their lattice structures, dielectric properties, insulating properties, and energy storage performances (ESPs). It is revealed that the introduction of SBAT can effectively enhance the relaxor behavior and optimize the P–E loops by inducing the coexistence of rhombohedral and tetragonal phases and disrupting long-range ferroelectricity due to compositional disorder, which leads to the enhanced ESPs. At x = 0.15, the sample exhibits a high W_rec of 3.06 J cm⁻³ with a favorable efficiency (η) of 72% under a LEF of 200 kV cm⁻¹, and demonstrates excellent insulating properties and considerable dielectric temperature stability. Additionally, a high discharge density W_dis of 1.40 J cm⁻³ and a notable power density P_D of 120 MW cm⁻³ can be achieved at 180 kV cm⁻¹. These findings suggest that 0.85NBT–0.15SBAT with favorable ESPs holds great potential for applications in DCCs under LEFs.