Enhanced energy-storage performance and thermal stability in Bi0.5Na0.5TiO3-based ceramics through defect engineering and composition design

Dielectric ceramics have been widely used in advanced microelectronics systems due to their inherent rapid charging/discharging capabilities and superb power density. However, concurrently attaining high energy storage density (Wrec), superior efficiency (η), and excellent thermal stability are arduous tasks for actual applications in dielectric ceramics. Herein, the introduction of predictable defects A-site vacancies (VA) and oxygen vacancies (VO) into the morphotropic phase boundary (MPB) of (Bi0.45La0.05Na0.5)0.94Ba0.06TiO3 (BLNBT) ceramics leads to a pinning effect in the grain boundary to improve the breakdown strength and energy storage performance. According to this strategy, the novel Sr0.8Bi0.1□0.1Ti0.8Zr0.2O2.95 (SBTZ)-modified BLNBT ceramics are designed and manufactured, which include SBTZ with a high relaxation behavior gene and BLNBT with an inherently high maximum polarization gene. As a result, a large Wrec of 3.84 J/cm3 with an excellent η of 90.8%, and outstanding charge/discharge capabilities (CD ∼ 584.99 A/cm2, PD ∼ 40.94 MW/cm3 and τ0.9 ∼ 95 ns) in the 0.75BLNBT-0.25SBTZ ceramic are achieved. Notably, the corresponding ceramic shows a slight degradation of Wrec with a variation of less than 8% (RT ∼ 200 °C), while the η remains at over 90%. The predictable defect engineering strategy proposed in this work is an effective way to develop new Bi0.5Na0.5TiO3-based systems with good energy storage performances.