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

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 2.16 J/cm³ and 70%, respectively, for a 100 μm thick sample under a 210 kV/cm voltage. When the film was rolled to a 60 μm thickness, the voltage strength increased to 330 kV/cm, leading to enhanced Wrec (5.33 J/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 1 Hz to 100 Hz 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 152 MW/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.