Enhanced dielectric energy storage performance of Na0.5Bi0.5TiO3-LiTaO3-based lead-free relaxor ferroelectric ceramics through domain structural regulation and improved densification

Abstract

Ceramic materials with relaxor dielectric properties, expressed as (1-x)(0.94Na0.5Bi0.5TiO3-0.06LiTaO3)-xCaTiO3 [(1-x)(NBT-LT)-xCT] with x values of 0.12, 0.15, 0.18, and 0.21, were synthesized through an A-site doping method to enhance energy storage capabilities. The linear dielectric CaTiO3 was chosen as the acceptor additive, and ceramic samples were prepared using conventional solid-phase and molding techniques. A comprehensive investigation evaluated the influence of different CT concentrations on the phase and energy storage/release characteristics of NBT-LT.Optimal performance was notably achieved with a 15% CT doping concentration, resulting in Wrec and η values of 2.16J/cm³ and 70%, respectively, for a 100 μm thick sample under a 210kV/cm voltage. When the film was rolled to a 60 μm thickness, the voltage strength increased to 330kV/cm, leading to enhanced Wrec (5.33J/cm³) and η (80%). Within the temperature range of 30 °C to 150 °C, only a marginal change in Wrec (less than 10%) was observed. Frequency conversion tests across the 1Hz to 100Hz range demonstrated the material's relative stability, with Wrec exhibiting minimal fluctuations. These findings emphasize the outstanding temperature and frequency stability of the material. During discharge, the material displayed a power density of up to 152MW/cm³, coupled with a discharge time of 0.3 μs, showcasing remarkable pulse discharge capabilities. The experimental results affirm the promising potential of (NBT-LT)-0.15CT lead-free relaxor ferroelectric ceramics for application in commercial capacitors.